Current opinion in Solid state Materials Science ELSEVIER Current Opinion in Solid State and Materials Science 6(2002)251-260 Application of electrophoretic and electrolytic deposition techniques in ceramIcs processing Aldo R. Boccaccini,, Igor Zhitomirsky Department of Materials, Imperial College of Science, Technology and Medicine, Prince Consort Rd, London SW7 2BP, UK Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario, Canada L&s 4L7 Abstract Electrodeposition is gaining increasing interest as a ceramic processing technique for a variety of technical applications. Major advances in the areas of electrophoretic deposition(EPD) and electrolytic deposition(ELD) achieved in the last 24 months include the well as a variety of advanced films and coatings for electronic, biomedical, optical, catalytic and electrochemical applicatlolde erials as fabrication of: electrodes and films for solid oxide fuel cells, fibre-reinforced and graded ceramic composites, nanostructured mate c 2002 Elsevier Science Ltd. All rights reserved 1. Introduction published in the last 2 years. During this period, key advances have been made towards understanding basic The two most prominent ceramic electrodeposition mechanisms of EPD and ELD, expanding traditional techniques, i.e. electrophoretic deposition(EPD)and elec- applications and exploring new application areas. For trolytic deposition(ELD), are gaining increasing interest reviews of developments before 2000 on EPD and ELD, both in academia and in the industrial sector, and a wide see Refs. [1, 2, 3 and [*], respectively range of novel applications in the processing of advanced ceramic materials and ceramic coatings is emerging. The interest in these processes is based not only on their high 2. Electrophoretic deposition(EPD) versatility to be used with different materials and combina- tions of materials but also because these are cost-effective The phenomenon of electrophoresis has been known techniques usually requiring simple equipment. Moreover since the beginning of the 19th century and it has found they have a high potential for scaling up to large product application in the past 40 years mainly in traditional volumes and variety of product shapes ceramic technology [1]. EPD is essentially a two-step EPD is achieved via motion of charged particles dis- process. In the first step, charged particles suspended in a persed in a liquid towards an electrode under an applied liquid migrate towards an electrode under the effect of an electric field. Deposit formation on the electrode is electric field (electrophoresis). In the second step, the achieved via particle coagulation particles deposit on the electrode forming a relatively ELD leads to thin ceramic films from solutions of metal dense and homogeneous compact or film. A post-EPD y production of colloidal particles in electrode processing step is usually required, which includes a reactions. Thus, electrode reactions in ELD and electro- suitable heat-treatment (firing or sintering) in order to phoretic motion of charged particles in EPD result in the further densify the deposits and to eliminate porosity accumulation of ceramic particles and formation of In general, EPD can be applied to any solid that is ceramic films at the relevant electrodes available in the form of a fine powder(<30 um)or a The present review covers the most recent and signifi- colloidal suspension. Indeed, examples of EPD of any cant developments in the areas of EPD and ELD material class can be found, including metals, polymers carbides, oxides, nitrides and glasses [1, **2, **31 Corresponding author. Tel: +44-20-7594-6731; fax: +44-20-7584- The potential of the EPD technique for the realization of unique microstructures and novel(and complex) materials E-mail address: aboccaccini@ ic ac uk(.R. Boccaccini) combinations in a variety of sha nd dimensions is 359-0286/02/S-see front matter 2002 Elsevier Science Ltd. All rights reserved PIl:S1359-0286(02)00080-3
Current Opinion in Solid State and Materials Science 6 (2002) 251–260 A pplication of electrophoretic and electrolytic deposition techniques in ceramics processing a, b Aldo R. Boccaccini , Igor Zhitomirsky * a Department of Materials, Imperial College of Science, Technology and Medicine, Prince Consort Rd., London SW7 2BP, UK b Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario, Canada L8S 4L7 Abstract Electrodeposition is gaining increasing interest as a ceramic processing technique for a variety of technical applications. Major advances in the areas of electrophoretic deposition (EPD) and electrolytic deposition (ELD) achieved in the last 24 months include the fabrication of: electrodes and films for solid oxide fuel cells, fibre-reinforced and graded ceramic composites, nanostructured materials as well as a variety of advanced films and coatings for electronic, biomedical, optical, catalytic and electrochemical applications. 2002 Elsevier Science Ltd. All rights reserved. 1. Introduction published in the last 2 years. During this period, key advances have been made towards understanding basic The two most prominent ceramic electrodeposition mechanisms of EPD and ELD, expanding traditional techniques, i.e. electrophoretic deposition (EPD) and elec- applications and exploring new application areas. For trolytic deposition (ELD), are gaining increasing interest reviews of developments before 2000 on EPD and ELD, both in academia and in the industrial sector, and a wide see Refs. [1,**2,**3] and [**4], respectively. range of novel applications in the processing of advanced ceramic materials and ceramic coatings is emerging. The interest in these processes is based not only on their high 2. Electrophoretic deposition (EPD) versatility to be used with different materials and combinations of materials but also because these are cost-effective The phenomenon of electrophoresis has been known techniques usually requiring simple equipment. Moreover since the beginning of the 19th century and it has found they have a high potential for scaling up to large product application in the past 40 years mainly in traditional volumes and variety of product shapes. ceramic technology [1]. EPD is essentially a two-step EPD is achieved via motion of charged particles dis- process. In the first step, charged particles suspended in a persed in a liquid towards an electrode under an applied liquid migrate towards an electrode under the effect of an electric field. Deposit formation on the electrode is electric field (electrophoresis). In the second step, the achieved via particle coagulation. particles deposit on the electrode forming a relatively ELD leads to thin ceramic films from solutions of metal dense and homogeneous compact or film. A post-EPD salts by production of colloidal particles in electrode processing step is usually required, which includes a reactions. Thus, electrode reactions in ELD and electro- suitable heat-treatment (firing or sintering) in order to phoretic motion of charged particles in EPD result in the further densify the deposits and to eliminate porosity. accumulation of ceramic particles and formation of In general, EPD can be applied to any solid that is ceramic films at the relevant electrodes. available in the form of a fine powder (,30 mm) or a The present review covers the most recent and signifi- colloidal suspension. Indeed, examples of EPD of any cant developments in the areas of EPD and ELD, as material class can be found, including metals, polymers, carbides, oxides, nitrides and glasses [1,**2,**3]. The potential of the EPD technique for the realization of *Corresponding author. Tel.: 144-20-7594-6731; fax: 144-20-7584- 3194. unique microstructures and novel (and complex) materials E-mail address: a.boccaccini@ic.ac.uk (A.R. Boccaccini). combinations in a variety of shapes and dimensions is 1359-0286/02/$ – see front matter 2002 Elsevier Science Ltd. All rights reserved. PII: S1359-0286(02)00080-3
252 A.R. Boccaccini, 1. Zhitomirsky/ Current Opinion in Solid State and Materials Science 6(2002)251-260 being increasingly appreciated by materials scientists and simulation of the epd process in particular seems to be a technologists. This growing interest in EPD both in the promising area where major R&D efforts are required academic and industrial communities has prompted the organization of the very first international conference focused entirely on the application of EPD in material 2. 2. Films for solid oxide fuel cells processing, sponsored by the United Engineering Founda- tion, which is being held in 2002 EPD is being increasingly considered for the fabrication of cathode- and anode-supported solid oxide fuel cells 2. 1. Fundamental principles of the EPD process (SOFC) of both planar and tubular geometry. Several recent papers describe the use of EPD in this area [12-18] The basic mechanisms of EPd have been extensively The relative advantages of EPD in SOFC manufacture considered in the literature mainly in the framework of the have been summarized recently by Negishi et al. [**13 Derjaguin-Landau-Verwey-Overbeek (DLvO)theory and They include: (i)coatings can be made in any shape, (ii)it particle double layer distortion on application of d. c. is possible to prepare porous coating as electrode and electric fields [**2]. There are however multiple theories dense coating as electrolyte by controlling deposition put forward to explain particle interactions and kinetics of conditions, (iii) laminate structures of electrodes and deposition [#2, **3], and further theoretical and modeling electrolyte can be readily obtained, and (iv) Ni-yttria work is being carried out. For example, studies of electro- stabilized zirconia(YSZ)cermets(anodes)can be obtained dynamic particle aggregation during EPd both under by electrophoretic co-deposition. In addition EPD has steady [5] and alternating [6] electric fields have been further advantages such as mass production possibility conducted recently, which have led to equations for the short formation times and simple equipment. Thus EPD time evolution of the probability of separation between makes it possible to simplify the fabrication process of deposited particles under different conditions. The models SoFC stacks with complex design architecture and there- are useful to explain the experimentally observed cluster- fore to achieve further cost reduction ing of colloidal particles deposited near an electrode in a In spite of the progress achieved recently in this area, DC electric field by considering convection by electro- many problems remain, which have been discussed by osmotic flow about the particles [7] Zhitomirsky and Petric [12]. Major difficulties are linked Numerical simulation has been used for the first time to the selection of adequate solvents and additives, in recently to model the buildup of a deposit of charged particular regarding the chemical compatibility of the particles on an electrode during EPD[8, 9]. These studies components of the binder-dispersant-solvent system are both of fundamental and practical interest as they solubility of the binder, as well as issues of viscosity and provide insight into local variations of particle interaction electrical resistivity of the suspension [191 processes during deposition, which can be used for optimi- The potential of the EPD technique for the fabrication of zation of EPD techniques. Another very important recent SOFCs with porous anode substrates and thin zirconia fundamental study on the formation of colloidal films electrolytes has been demonstrated by Will et al. [16], who during EPD has been provided by Sarkar et al. [**10]. investigated the deposition of zirconia from ethanol sus- They observed the deposition of silica particles on silicon pensions on porous NiO/CeO,/ZrO, substrates. Another ers as a function of deposition time, and compared advancement was reported recently by Basu et al.[171 nucleation and growth of the silica particle layer with that who investigated the fabrication of dense zirconia elec- of atomic film growth via molecular-beam epitaxy. a trolyte films for tubular SOFCs by EPD Summarizing, the striking similarity was found between the two growth current research and development efforts in this area are processes. This indicates possible new directions for promising and encourage a very optimistic view for the further research as the equivalence between the two future use of EPD in SOFC manufacture processes provides insight into the growth kinetics of EPD films and can be used for their microstructural optimi- zation 23. Coatings on solids substrates Another fundamental study with practical relevance was conducted by Ferrari et al., who investigated the galvanic EPD has been the processing technique of choice for reactions occurring at the electrodes during EPd fro production of ceramic coatings on a variety of substrates aqueous suspensions [ Ill for numerous applications, which include wear and oxida- The analysis of the literature reveals however that there tion resistance, bioactive coatings for biomedical implants is need for further theoretical and modeling work. Most and devices as well as functional coatings for electronic experimental research is currently carried out following magnetic and related applications [ **2, *31 unsatisfactory and time-consuming trial-and-error ap- Current interest in the fabrication of wear and abrasion proaches, due to the lack of predictive models linking EPD resistant coatings is focused on developing metal/ceramic process parameters and deposit properties. The numerical and ceramic/ceramic composite coatings. EPD, usually in
252 A.R. Boccaccini, I. Zhitomirsky / Current Opinion in Solid State and Materials Science 6 (2002) 251–260 being increasingly appreciated by materials scientists and simulation of the EPD process in particular seems to be a technologists. This growing interest in EPD both in the promising area where major R&D efforts are required. academic and industrial communities has prompted the organization of the very first international conference focused entirely on the application of EPD in materials 2 .2. Films for solid oxide fuel cells processing, sponsored by the United Engineering Foundation, which is being held in 2002. EPD is being increasingly considered for the fabrication of cathode- and anode-supported solid oxide fuel cells 2 .1. Fundamental principles of the EPD process (SOFC) of both planar and tubular geometry. Several recent papers describe the use of EPD in this area [12–18]. The basic mechanisms of EPD have been extensively The relative advantages of EPD in SOFC manufacture considered in the literature mainly in the framework of the have been summarized recently by Negishi et al. [**13]. Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and They include: (i) coatings can be made in any shape, (ii) it particle double layer distortion on application of d.c. is possible to prepare porous coating as electrode and electric fields [**2]. There are however multiple theories dense coating as electrolyte by controlling deposition put forward to explain particle interactions and kinetics of conditions, (iii) laminate structures of electrodes and deposition [**2,**3], and further theoretical and modeling electrolyte can be readily obtained, and (iv) Ni-yttria work is being carried out. For example, studies of electro- stabilized zirconia (YSZ) cermets (anodes) can be obtained dynamic particle aggregation during EPD both under by electrophoretic co-deposition. In addition EPD has steady [5] and alternating [6] electric fields have been further advantages such as mass production possibility, conducted recently, which have led to equations for the short formation times and simple equipment. Thus EPD time evolution of the probability of separation between makes it possible to simplify the fabrication process of deposited particles under different conditions. The models SOFC stacks with complex design architecture and thereare useful to explain the experimentally observed cluster- fore to achieve further cost reduction. ing of colloidal particles deposited near an electrode in a In spite of the progress achieved recently in this area, DC electric field by considering convection by electro- many problems remain, which have been discussed by osmotic flow about the particles [7]. Zhitomirsky and Petric [12]. Major difficulties are linked Numerical simulation has been used for the first time to the selection of adequate solvents and additives, in recently to model the buildup of a deposit of charged particular regarding the chemical compatibility of the particles on an electrode during EPD [8,*9]. These studies components of the binder–dispersant–solvent system, are both of fundamental and practical interest as they solubility of the binder, as well as issues of viscosity and provide insight into local variations of particle interaction electrical resistivity of the suspension [19]. processes during deposition, which can be used for optimi- The potential of the EPD technique for the fabrication of zation of EPD techniques. Another very important recent SOFCs with porous anode substrates and thin zirconia fundamental study on the formation of colloidal films electrolytes has been demonstrated by Will et al. [16], who during EPD has been provided by Sarkar et al. [**10]. investigated the deposition of zirconia from ethanol susThey observed the deposition of silica particles on silicon pensions on porous NiO/CeO /ZrO substrates. Another 2 2 wafers as a function of deposition time, and compared the advancement was reported recently by Basu et al. [*17], nucleation and growth of the silica particle layer with that who investigated the fabrication of dense zirconia elecof atomic film growth via molecular-beam epitaxy. A trolyte films for tubular SOFCs by EPD. Summarizing, the striking similarity was found between the two growth current research and development efforts in this area are processes. This indicates possible new directions for promising and encourage a very optimistic view for the further research as the equivalence between the two future use of EPD in SOFC manufacture. processes provides insight into the growth kinetics of EPD films and can be used for their microstructural optimization. 2 .3. Coatings on solids substrates Another fundamental study with practical relevance was conducted by Ferrari et al., who investigated the galvanic EPD has been the processing technique of choice for the reactions occurring at the electrodes during EPD from production of ceramic coatings on a variety of substrates aqueous suspensions [*11]. for numerous applications, which include wear and oxidaThe analysis of the literature reveals however that there tion resistance, bioactive coatings for biomedical implants is need for further theoretical and modeling work. Most and devices as well as functional coatings for electronic, experimental research is currently carried out following magnetic and related applications [**2,**3]. unsatisfactory and time-consuming trial-and-error ap- Current interest in the fabrication of wear and abrasion proaches, due to the lack of predictive models linking EPD resistant coatings is focused on developing metal/ceramic process parameters and deposit properties. The numerical and ceramic/ceramic composite coatings. EPD, usually in
A.R. Boccaccini, 1. Zhitomirsky/ Current Opinion in Solid State and Materials Science 6(2002)251-260 combination with electroplating or galvanic deposition of 2. 4. Coatings on fibres, porous substrates and composite coatings (20, "217. production of metal/ ceramic membranes In recent developments, yttria stabilized zirconia/alumina composite coatings were pro- EPD is being used increasingly to coat fibres and porous duced on Fecralloys by Wang et al. [22 by using EPI ubstrates with ceramic materials for applications ranging and a reaction bonding processes. Certainly, the main from filters and porous carriers to bioactive coatings and difficulty of producing ceramic coatings on metal hollow fibre fabrication The successful use of epd for strates using Epd is that the metal substrates cannot coating carbon and metallic fibrous substrates with alumina withstand the high temperature required for sintering the and titania nanopowders was shown by Boccaccini et al deposited ceramic coating. Therefore optimized densifica- [37]. The coated porous fibrous structures are intended for tion techniques requiring lower temperatures must be high-temperature filtration of fluids, where the titania or developed. Wang et al. showed that reaction bonding is an alumina coatings act as oxidation and corrosion protective excellent alternative [22]. Further R&D efforts are how- layers. A recent paper by Zhitomirsky [38] demonstrates ever required in this important technological area the coating of carbon fibres with hydroxyapatite(HA) EPD has been recently used in ceramic joining applica- After burning out the fibrous carbon substrates hollow HA tions Mixtures of SiC or Si3, and reactive carbon were fibres of various diameters were obtained. EPD has been deposited onto SiC or Sis, parts in preparation for used by Su et al. [39 to deposit lead zirconate titanate reaction bonding with molten silicon [23]. The results of (PZT)films(<5 um)on Pt wires. In this case, EPD allows Lessing et al. are significant as they show for the first time for the use of PzT nanoparticles directly from hydrother how the combination of EPD and reaction bonding allow mal suspensions, thus avoiding agglomeration of particles for the fabrication of large complex structures manufac and resulting in lower sintering temperatures tured from smaller components made of Sic or Si,N4 Membranes and porous materials have also been pre *23] pared recently by EPD techniques, including zeolite [40] The availability of ceramic nanopowders in numerous and alumina [41] membranes. The electrophoretic assem- compositions enables the use of EPD to prepare dielectric, bly of nanozeolites has been investigated by Ke et al. [42] magnetic, semiconducting and superconducting ceramic They were able to prepare hollow zeolite fibres by coating thick films for a variety of applications in electronics. nanozeolites onto carbon fibres and subsequent burn-out of Moreover EPD allows for the fabrication of engineered the carbon core. Significant related research focusing on non-planar structures made of functional ceramics which EPD of zeolites was carried out by Ahlers et al. [43], who find application developed a method for fabricating optimized zeolite- Current work in these areas is leading to encouraging modified electrodes for applications in electroanalysis and results and therefore merit further R&D efforts. Some electrocatalysis recent significant developments include the fabrication of BaTiO, thick films for sensor and actuator applications 2.5. Fibre reinforced ceramic matrix composites 4, Zno thick films for gas sensors [25], zirconia films on porous Lao. Sro. MnO, substrates [26], MgO-modified EPD is a simple and cost-effective method for Bao Sro. 4TiO, thick films for tunable microwave devices ing high-quality fibre reinforced ceramic matrix [27, LiCoo, electrodes for rechargeable lithium batteries ites. In this application, EPD is used to infiltrate preforms [28], phosphor screens for plasma display panel applica- with tight two- or three-dimensional fibre architectures tions [29], photocatalytic titania coatings [30] and Mgo using nanosized ceramic particles. A recent comprehensive hick films for electronics [31, 32 review article reveals the great variety of conducting and Furthermore, the fabrication of high-temperature non-conducting fibre and matrix combinations that have conducting films of controlled thickness on substrates of been explored, including SiC, carbon, and oxide ceramic various shapes and dimensions by EPD is gaining increas- fibre architectures and silica, borosilicate glass, alumina, ing interest [33, *34]. The significant advantages of EPD zirconia, mullite, hydroxyapatite, SiC and Si3 N, matrices over other coating techniques for continuous fabrication of [**44]. Most recent work has been devoted to Ni-coated superconducting coatings include the suitability of EPD to carbon fibre reinforced alumina [45], borosilicate glass be scaled up and adapted to the coating of large areas as matrix composites [46], C-fibre reinforced Sic matrix well as the high deposition rate that can be achieved composites [47] and silica/silica composites [48]. More- over EPD has been recently shown to be an excellent A final area of successful application of EPD in coating pre-infiltration step for decreasing processing time of chnology is in the biomedical materials field. In par- chemical vapour infiltration of SiC-fibre reinforced Sic ticular, the improvement of the EPD technique for deposi- matrix composites [491 tion of bioactive hydroxyapatite and related calci Both aqueous and non-aqueous suspensions have been phosphate films on biocompatible metallic substrates(e.g. used and the different factors affecting the EPD behavior TiAl4V alloys) has been recently reported [35, 36 of ceramic sols and their optimization to obtain high
A.R. Boccaccini, I. Zhitomirsky / Current Opinion in Solid State and Materials Science 6 (2002) 251–260 253 combination with electroplating or galvanic deposition of 2 .4. Coatings on fibres, porous substrates and metals, is being used for the production of metal/ceramic membranes composite coatings [20,*21]. In recent developments, yttria stabilized zirconia/alumina composite coatings were pro- EPD is being used increasingly to coat fibres and porous duced on Fecralloys by Wang et al. [*22] by using EPD substrates with ceramic materials for applications ranging and a reaction bonding processes. Certainly, the main from filters and porous carriers to bioactive coatings and difficulty of producing ceramic coatings on metal sub- hollow fibre fabrication. The successful use of EPD for strates using EPD is that the metal substrates cannot coating carbon and metallic fibrous substrates with alumina withstand the high temperature required for sintering the and titania nanopowders was shown by Boccaccini et al. deposited ceramic coating. Therefore optimized densifica- [37]. The coated porous fibrous structures are intended for tion techniques requiring lower temperatures must be high-temperature filtration of fluids, where the titania or developed. Wang et al. showed that reaction bonding is an alumina coatings act as oxidation and corrosion protective excellent alternative [*22]. Further R&D efforts are how- layers. A recent paper by Zhitomirsky [*38] demonstrates ever required in this important technological area. the coating of carbon fibres with hydroxyapatite (HA). EPD has been recently used in ceramic joining applica- After burning out the fibrous carbon substrates hollow HA tions. Mixtures of SiC or Si N and reactive carbon were fibres of various diameters were obtained. EPD has been 3 4 deposited onto SiC or Si N parts in preparation for used by Su et al. [39] to deposit lead zirconate titanate 3 4 reaction bonding with molten silicon [*23]. The results of (PZT) films (,5 mm) on Pt wires. In this case, EPD allows Lessing et al. are significant as they show for the first time for the use of PZT nanoparticles directly from hydrotherhow the combination of EPD and reaction bonding allow mal suspensions, thus avoiding agglomeration of particles for the fabrication of large complex structures manufac- and resulting in lower sintering temperatures. tured from smaller components made of SiC or Si N Membranes and porous materials have also been pre- 3 4 [*23]. pared recently by EPD techniques, including zeolite [40] The availability of ceramic nanopowders in numerous and alumina [41] membranes. The electrophoretic assemcompositions enables the use of EPD to prepare dielectric, bly of nanozeolites has been investigated by Ke et al. [42]. magnetic, semiconducting and superconducting ceramic They were able to prepare hollow zeolite fibres by coating thick films for a variety of applications in electronics. nanozeolites onto carbon fibres and subsequent burn-out of Moreover EPD allows for the fabrication of engineered the carbon core. Significant related research focusing on non-planar structures made of functional ceramics which EPD of zeolites was carried out by Ahlers et al. [*43], who find applications in microsystems technologies. developed a method for fabricating optimized zeoliteCurrent work in these areas is leading to encouraging modified electrodes for applications in electroanalysis and results and therefore merit further R&D efforts. Some electrocatalysis. recent significant developments include the fabrication of BaTiO thick films for sensor and actuator applications 2 .5. Fibre reinforced ceramic matrix composites 3 [24], ZnO thick films for gas sensors [25], zirconia films on porous La Sr MnO substrates [26], MgO-modified EPD is a simple and cost-effective method for fabricat- 0.9 0.1 3 Ba Sr TiO thick films for tunable microwave devices ing high-quality fibre reinforced ceramic matrix compos- 0.6 0.4 3 [27], LiCoO electrodes for rechargeable lithium batteries ites. In this application, EPD is used to infiltrate preforms 2 [28], phosphor screens for plasma display panel applica- with tight two- or three-dimensional fibre architectures tions [29], photocatalytic titania coatings [30] and MgO using nanosized ceramic particles. A recent comprehensive thick films for electronics [31,32]. review article reveals the great variety of conducting and Furthermore, the fabrication of high-temperature super- non-conducting fibre and matrix combinations that have conducting films of controlled thickness on substrates of been explored, including SiC, carbon, and oxide ceramic various shapes and dimensions by EPD is gaining increas- fibre architectures and silica, borosilicate glass, alumina, ing interest [33,**34]. The significant advantages of EPD zirconia, mullite, hydroxyapatite, SiC and Si N matrices 3 4 over other coating techniques for continuous fabrication of [**44]. Most recent work has been devoted to Ni-coated superconducting coatings include the suitability of EPD to carbon fibre reinforced alumina [45], borosilicate glass be scaled up and adapted to the coating of large areas as matrix composites [46], C-fibre reinforced SiC matrix well as the high deposition rate that can be achieved composites [47] and silica/silica composites [48]. More- [**34]. over EPD has been recently shown to be an excellent A final area of successful application of EPD in coating pre-infiltration step for decreasing processing time of technology is in the biomedical materials field. In par- chemical vapour infiltration of SiC-fibre reinforced SiC ticular, the improvement of the EPD technique for deposi- matrix composites [49]. tion of bioactive hydroxyapatite and related calcium Both aqueous and non-aqueous suspensions have been phosphate films on biocompatible metallic substrates (e.g. used and the different factors affecting the EPD behavior TiAl4V alloys) has been recently reported [35,36]. of ceramic sols and their optimization to obtain high
A.R. Boccaccini, 1. Zhitomirsky/ Current Opinion in Solid State and Materials Science 6(2002)251-260 presented in Ref [50] where the fabrication of compos- ites of tubular shape is demonstrated. The EPD cell used is shown schematically in Fig. 2[50]. Major advances in this area are expected, in particular related to the furthe development of the EPD technique for the fabrication of oxide fibre-oxide matrix ceramic composites with high systems are those by Kooner et al. [51] and Manocha et al [48]. Efforts should however concentrate on the production of complex shape components, for which the EPD tech- nique may represent the most technically viable and cost effective option. 2. 6. Laminated and graded composites Fig. 1. SEM micrograph of EPD-infiltrated SiC (Nicalon")fibre mat using a mixed colloidal suspension of mullite composition. A high-level EPD has been used successfully to fabricate ceramic infiltration is seen which leads to porous-f laminated composites and graded materials. Developments opposites [44 up to 2000 are covered in Ref [**3]. Recent advances in functionally graded materials(FGM) have been reported by Put et al. [52, 53. They manufactured graded wC-Co fibre preforms are now quite well composites using a suspension of wc powder in acetone understood The pH of the solution, the applied with variable Co powder content. In another significant voltage and deposition time are shown to have a strong development by the same group, anodic co-deposition of ence on the quality of the infiltration. Good particle Al,O3 and CeO, -stabilised zirconia powders was used to packing and a high solids-loading can be achieved, produc- obtain cylindrical and tubular-shaped Al, O, /zirconia ing firm ceramic deposits which adhered to the fibres, thus FGM components [*54] leading to pore-free composites after a post-EPD heat- Current efforts are devoted to the development of EPD treatment process. The typical microstructure of a mullite fabrication approaches for laminated ceramic composites, matrix composite reinforced by SiC (Nicalon ) fibres in particular in the system zirconia/alumina, due to the fabricated by EPD is shown in Fig. I high fracture resistance of these structures [55-57. The Most previous research summarized in Ref. [**44] has significance of the papers by Moreno and Ferrari [56] and been focused on components of simple planar shape. The by Uchikoshi et al. [571, is that they focus on optimized use of EPD for near-net shape fabrication of 3-D compo- aqueous suspensions, which should be always preferred ite components of complex shapes is starting to be over organic suspensions due to environmental and econ- investigated. A pioneering development in this area is omic considerations. Based on the promising results balance woven fibre mat in tube form as deposition electrode(-)d. c. central electrode+dc outer electrode(+)d.c boehmite(r-AlOOHD) sol glass container Fig. 2. Schema of the EPD cell recently introduced for the fabrication of tubular metal fibre reinforced alumina matrix composites [ 50](diagram courtesy Dr C Kaya, University of Birmingham, UK)
254 A.R. Boccaccini, I. Zhitomirsky / Current Opinion in Solid State and Materials Science 6 (2002) 251–260 presented in Ref. [*50], where the fabrication of composites of tubular shape is demonstrated. The EPD cell used is shown schematically in Fig. 2 [*50]. Major advances in this area are expected, in particular related to the further development of the EPD technique for the fabrication of oxide fibre-oxide matrix ceramic composites with high oxidation resistance. Recent promising results in these systems are those by Kooner et al. [51] and Manocha et al. [48]. Efforts should however concentrate on the production of complex shape components, for which the EPD technique may represent the most technically viable and costeffective option. 2 .6. Laminated and graded composites Fig. 1. SEM micrograph of EPD-infiltrated SiC (Nicalon ) fibre mat EPD has been used successfully to fabricate ceramic using a mixed colloidal suspension of mullite composition. A high-level of ceramic infiltration is seen which leads to porous-free ceramic laminated composites and graded materials. Developments composites [**44]. up to 2000 are covered in Ref. [**3]. Recent advances in functionally graded materials (FGM) have been reported by Put et al. [52,53]. They manufactured graded WC–Co infiltration of the fibre preforms are now quite well composites using a suspension of WC powder in acetone understood [**44]. The pH of the solution, the applied with variable Co powder content. In another significant voltage and deposition time are shown to have a strong development by the same group, anodic co-deposition of influence on the quality of the infiltration. Good particle Al O and CeO -stabilised zirconia powders was used to 23 2 packing and a high solids-loading can be achieved, produc- obtain cylindrical and tubular-shaped Al O /zirconia 2 3 ing firm ceramic deposits which adhered to the fibres, thus FGM components [*54]. leading to pore-free composites after a post-EPD heat- Current efforts are devoted to the development of EPD treatment process. The typical microstructure of a mullite fabrication approaches for laminated ceramic composites, matrix composite reinforced by SiC (Nicalon ) fibres in particular in the system zirconia/alumina, due to the fabricated by EPD is shown in Fig. 1. high fracture resistance of these structures [55–57]. The Most previous research summarized in Ref. [**44] has significance of the papers by Moreno and Ferrari [56] and been focused on components of simple planar shape. The by Uchikoshi et al. [57], is that they focus on optimized use of EPD for near-net shape fabrication of 3-D compo- aqueous suspensions, which should be always preferred site components of complex shapes is starting to be over organic suspensions due to environmental and econinvestigated. A pioneering development in this area is omic considerations. Based on the promising results Fig. 2. Schema of the EPD cell recently introduced for the fabrication of tubular metal fibre reinforced alumina matrix composites [*50] (diagram courtesy Dr C. Kaya, University of Birmingham, UK)
A.R. Boccaccini, 1. Zhitomirsky/ Current Opinion in Solid State and Materials Science 6(2002)251-260 achieved so far, a significant growth of r&D work in the 3. Electrolytic deposition(ELD) area of EPD processing of FGM and laminated ceramic structures is anticipated Electrolytic deposition produces thin ceramic films from solutions of metal salts and it is a relatively new technique in ceramic processing. There are several basic mechanism 2.7. Nanomaterials and nanostructures of ELD of ceramic films. Cathodic electrolytic deposition has important advantages and can be used for deposition of The synthesis and characterisation of nanostructured various oxide materials. In the cathodic electrodeposition materials and nanostructures are areas of active research. method, cathodic reactions are used to generate OH-groups The main focus of the research on nanostructured material and increase the pH at the electrode. Metal ions o is to gain basic understanding of their intriguing physical complexes, which are stable in the bulk of solutions at low and chemical properties, and EPD, with its high versatility pH, are hydrolyzed by electrogenerated base at the elec and ease of application, is revealing itself as one of the trode surface to form colloidal particles. These particles processing techniques of choice in this increasingly popu- coagulate to form cathodic ceramic deposits lar research area. For example, EPD has been used for the A comprehensive review paper covering developments growth of ceramic nanotubes and nanorods and for the in ELD of ceramic materials before 2000 has been efficient deposit of nanotubes and nanosized ceramic published by Therese and Kamath [**4] particles on different substrates [*58, 59, 60,611 Several studies have recently contributed to both the A major advantage of EpD for the fabrication of fundamental understanding of the mechanisms of ELD and nanorods and nanowires is the ability to grow large areas the practical use of ELD for various applications. The most of uniformly sized and nearly unidirectionally aligned significant advances are summarized in this section nanorods of various oxides, as described by Limmer et al [* 58]. Fig 3 shows the typical structure of TiO, nanorods 3.1. Fundamental principles of the eld process grown in a polycarbonate membrane with 200-nm diameter pores by sol-gel EPD[**581 Recent progress [**64 in the understanding of the Smeets et al. [62] have recently used EPD to incorporate mechanism of cathodic electrodeposition has come from functional nanosized particles into nanoporous glass the application of the classical DLvo theory of colloidal bodies. The main advantage of the EPD technique here is stability. Electrolyte concentration in the solutions used for that it involves lower temperatures than traditional glass ELD exceeds the flocculation values for corresponding melting, and thus components with relatively low thermal ions. Therefore colloidal particles obtained by cathodic capability can be incorporated into glass hosts, as for electrosynthesis are unstable and coagulate to form a example Cds/Se nanoparticles. A related study was con- cathodic deposit. The important recent finding is that the ducted by Subramanian et al.[63], who deposited noble formation of a ceramic deposit during ELD is caused by metal particles of Au, Pt and Ir on nanostructured titania flocculation introduced by the electrolyte **64]. The films using epd study also highlighted the importance of the electric field Although the development of EPD techniques in this electrode reactions and other factors that influence the novel area(nanomaterials and nanostructures) is in the coagulation of particles near the electrode surface. In a initial stage, results so far are encouraging and indicate recent review, novel electrochemical strategies and de- great potential for future R&D efforts velopments of cathodic electrodeposition, focusing on the Fig 3. Typical structure of TiO, nanorods grown in a membrane with 200-nm diameter pores by sol-gel EPD, as produced by Limmer et al. [58], at(A) w and(B) high magnification(micrograph courtesy of Professor G Cao, published with permission of Wiley-VCH, Weinheim
A.R. Boccaccini, I. Zhitomirsky / Current Opinion in Solid State and Materials Science 6 (2002) 251–260 255 achieved so far, a significant growth of R&D work in the 3. Electrolytic deposition (ELD) area of EPD processing of FGM and laminated ceramic structures is anticipated. Electrolytic deposition produces thin ceramic films from solutions of metal salts and it is a relatively new technique in ceramic processing. There are several basic mechanisms 2 .7. Nanomaterials and nanostructures of ELD of ceramic films. Cathodic electrolytic deposition has important advantages and can be used for deposition of The synthesis and characterisation of nanostructured various oxide materials. In the cathodic electrodeposition materials and nanostructures are areas of active research. method, cathodic reactions are used to generate OH-groups The main focus of the research on nanostructured materials and increase the pH at the electrode. Metal ions or is to gain basic understanding of their intriguing physical complexes, which are stable in the bulk of solutions at low and chemical properties, and EPD, with its high versatility pH, are hydrolyzed by electrogenerated base at the elecand ease of application, is revealing itself as one of the trode surface to form colloidal particles. These particles processing techniques of choice in this increasingly popu- coagulate to form cathodic ceramic deposits. lar research area. For example, EPD has been used for the A comprehensive review paper covering developments growth of ceramic nanotubes and nanorods and for the in ELD of ceramic materials before 2000 has been efficient deposit of nanotubes and nanosized ceramic published by Therese and Kamath [**4]. particles on different substrates [**58,*59,*60,61]. Several studies have recently contributed to both the A major advantage of EPD for the fabrication of fundamental understanding of the mechanisms of ELD and nanorods and nanowires is the ability to grow large areas the practical use of ELD for various applications. The most of uniformly sized and nearly unidirectionally aligned significant advances are summarized in this section. nanorods of various oxides, as described by Limmer et al. [**58]. Fig. 3 shows the typical structure of TiO nanorods 3 .1. Fundamental principles of the ELD process 2 grown in a polycarbonate membrane with 200-nm diameter pores by sol–gel EPD [**58]. Recent progress [**64] in the understanding of the Smeets et al. [62] have recently used EPD to incorporate mechanism of cathodic electrodeposition has come from functional nanosized particles into nanoporous glass the application of the classical DLVO theory of colloidal bodies. The main advantage of the EPD technique here is stability. Electrolyte concentration in the solutions used for that it involves lower temperatures than traditional glass ELD exceeds the flocculation values for corresponding melting, and thus components with relatively low thermal ions. Therefore colloidal particles obtained by cathodic capability can be incorporated into glass hosts, as for electrosynthesis are unstable and coagulate to form a example CdS/Se nanoparticles. A related study was con- cathodic deposit. The important recent finding is that the ducted by Subramanian et al. [63], who deposited noble formation of a ceramic deposit during ELD is caused by metal particles of Au, Pt and Ir on nanostructured titania flocculation introduced by the electrolyte [**64]. The films using EPD. study also highlighted the importance of the electric field, Although the development of EPD techniques in this electrode reactions and other factors that influence the novel area (nanomaterials and nanostructures) is in the coagulation of particles near the electrode surface. In a initial stage, results so far are encouraging and indicate recent review, novel electrochemical strategies and degreat potential for future R&D efforts. velopments of cathodic electrodeposition, focusing on the Fig. 3. Typical structure of TiO nanorods grown in a membrane with 200-nm diameter pores by sol–gel EPD, as produced by Limmer et al. [**58], at (A) 2 low and (B) high magnification (micrograph courtesy of Professor G. Cao, published with permission of Wiley–VCH, Weinheim, Germany)
A.R. Boccaccini, 1. Zhitomirsky/ Current Opinion in Solid State and Materials Science 6(2002)251-260 properties of ceramic coatings could be improved by the 3. 2. Coatings for electronic, catalytic and optical use of additives [74, 75 pplications The interest in ELD for fuel cell applications stems from the need to decrease the thickness of the electrolyte layer lectrolytic deposition has aroused considerable interest and deposit intermediate layers preventing interfacial for the development of thin films of titania and complex electrode-electrolyte degradation at elevated temperatures titanates for applications in electronics [ 64, 66]. What is Thin films of yttria stabilized zirconia and Ce -Gd, o2 very important about this recent work is that a relatively were prepared by cathodic electrolytic deposition [76,77] low temperature is required for film crystallization, i.e. the It was shown that the critical thickness of electrolyti formation of a perovskite phase was observed at 500C deposits achievable without crack formation could be Ishikawa and Matsumoto [67] used alternative elec- increased using a cationic polyelectrolyte with inherent trolysis in(NH4)2TIO(C2 O4)2] solutions for electrodepo- binding properties [771 sition of TiO2 into porous substrates. The deposits showed high photocatalytic activity for the decomposition of 3.4. Biomedical applications acetaldehyde. Another important approach is based on anodic oxidative hydrolysis of TiCl,. This method was Considerable attention has been given to electrodeposi- applied recently to produce TiO, nanowires [68]. Well- tion of ceramic coatings for biomedical applications. The aligned TiO, nanowire arrays prepared by this method interest in electrolytic deposition for implant development could be useful for photoelectrochemical applications stems from the possibility of deposition on substrates of Pauporte and Lincot [**69]reported epitaxial growth of complex shape and the high purity of the deposits inc oxide films on single crystal Gan layers. Prepared Dinamani and Kamath prepared various phosphate materi films exhibited good optical and luminescence properties. als using cathodic electrodeposition [78]. Electrodeposition The important finding was the possibility of tuning of film of hydroxyapatite coatings in basic conditions was reported properties by changing the applied potential, bath com- by Manso and co-workers [79]. These hydroxyapatite position or by post-deposition thermal treatments. Of coatings exhibited good adhesion to the substrates. Elec particular importance is the recently demonstrated possi- trolytic ZrO, coatings were deposited on Co-Cr-Mo bility of epitaxial depos of Zno nanopillars onto implant alloys for hip prosthesis [801 Au(111), Au(1 10)and Au(100) single crystal substrates The problem of cracking in electrolytic zirconia deposits [701. It was suggested that these nanopillars could be used hich usually occurs upon drying has recently been s templates for molecular electronics and for data storage. addressed by the use of polymer additives [*81, **82]. It The increasing interest in applications of Zno films was shown [81 that poly(diallyldimethylammonium resulted in further development of electrochemical strate- chloride)(PDDA) acts as a binder, providing better gies for film deposition. Pauporte and Lincot ["71] demon- adhesion of zirconia deposits and preventing cracking. An strated for example cathodic electrodeposition of Zno important finding was that the amount of organic phase in dissolved hydrogen the oxygen pre the deposits could be changed by variation of PDDa cursor concentration in solutions. These results pave the way for There is also a growing interest in electrodeposition of ELd of thick hybrid bioactive organic-inorganic films dye-modified ZnO films [72]. An interesting observation is that the adsorption of the dyes modifies the crystal growth 3.5. Hybrid nanostructured films and surface morphology of Zno films A promising ELD approach has been exploited for Electrodeposition of various hybrid materials based on preparation of macroporous Zno films [*73]. In this oxides or hydroxides of Zr, Ce, Gd, Fe, Ni, Cr, Y, Cu, Co, method highly ordered macroporous Zno films were La and charged or neutral polymers was recently reported electrodeposited using polystyrene colloidal crystals as [81, 82]. It was shown that composition, nanostructure templates. These results pave the way for formation of and morphology of the films could be tailored by variation advanced films combining photonic, luminescent and of bath compositions, deposition parameters and mass piezoelectric properties. Similar strategies used transport conditions for organic and inorganic components for a number of other photonic crystals The microstructure of an optimized hybrid ceria-PDDA/ zirconia-PDDA laminate film on a graphite substrate 3.3. High-temperature coatings and solid oxide fuel cells prepared by method developed in Ref. [81], is shown in Fig. 4. The results obtained are significant for electrodepo- le mportant developments were reported in the field of sition of hybrid thick films. These nanocomposites not ctrodeposition of materials for high temperature applica- only combine the advantageous properties of organic and tions. Advanced ceramic coatings were deposited for inorganic components but also exhibit novel properties
256 A.R. Boccaccini, I. Zhitomirsky / Current Opinion in Solid State and Materials Science 6 (2002) 251–260 fundamentals and principles of the process, have been protection of stainless steel against oxidation at high covered [*65]. temperatures [*74,75]. It was demonstrated that protective properties of ceramic coatings could be improved by the 3 .2. Coatings for electronic, catalytic and optical use of additives [*74,75]. applications The interest in ELD for fuel cell applications stems from the need to decrease the thickness of the electrolyte layer Electrolytic deposition has aroused considerable interest and deposit intermediate layers preventing interfacial for the development of thin films of titania and complex electrode–electrolyte degradation at elevated temperatures. titanates for applications in electronics [**64,*66]. What is Thin films of yttria stabilized zirconia and Ce Gd O 12x x 22y very important about this recent work is that a relatively were prepared by cathodic electrolytic deposition [76,77]. low temperature is required for film crystallization, i.e. the It was shown that the critical thickness of electrolytic formation of a perovskite phase was observed at 500 8C. deposits achievable without crack formation could be Ishikawa and Matsumoto [67] used alternative elec- increased using a cationic polyelectrolyte with inherent trolysis in (NH ) [TiO(C O ) ] solutions for electrodepo- binding properties [77]. 42 2 42 sition of TiO into porous substrates. The deposits showed 2 high photocatalytic activity for the decomposition of 3 .4. Biomedical applications acetaldehyde. Another important approach is based on anodic oxidative hydrolysis of TiCl . This method was Considerable attention has been given to electrodeposi- 3 applied recently to produce TiO nanowires [68]. Well- tion of ceramic coatings for biomedical applications. The 2 aligned TiO nanowire arrays prepared by this method interest in electrolytic deposition for implant development 2 could be useful for photoelectrochemical applications. stems from the possibility of deposition on substrates of Pauporte and Lincot [**69] reported epitaxial growth of complex shape and the high purity of the deposits. zinc oxide films on single crystal GaN layers. Prepared Dinamani and Kamath prepared various phosphate materi- films exhibited good optical and luminescence properties. als using cathodic electrodeposition [78]. Electrodeposition The important finding was the possibility of tuning of film of hydroxyapatite coatings in basic conditions was reported properties by changing the applied potential, bath com- by Manso and co-workers [79]. These hydroxyapatite position or by post-deposition thermal treatments. Of coatings exhibited good adhesion to the substrates. Elecparticular importance is the recently demonstrated possi- trolytic ZrO coatings were deposited on Co–Cr–Mo 2 bility of epitaxial deposition of ZnO nanopillars onto implant alloys for hip prosthesis [80]. Au(111), Au(110) and Au(100) single crystal substrates The problem of cracking in electrolytic zirconia deposits [*70]. It was suggested that these nanopillars could be used which usually occurs upon drying has recently been as templates for molecular electronics and for data storage. addressed by the use of polymer additives [*81,**82]. It The increasing interest in applications of ZnO films was shown [*81] that poly(diallyldimethylammonium resulted in further development of electrochemical strate- chloride) (PDDA) acts as a binder, providing better gies for film deposition. Pauporte and Lincot [*71] demon- adhesion of zirconia deposits and preventing cracking. An strated for example cathodic electrodeposition of ZnO important finding was that the amount of organic phase in using dissolved hydrogen peroxide as the oxygen pre- the deposits could be changed by variation of PDDA cursor. concentration in solutions. These results pave the way for There is also a growing interest in electrodeposition of ELD of thick hybrid bioactive organic–inorganic films. dye-modified ZnO films [72]. An interesting observation is that the adsorption of the dyes modifies the crystal growth 3 .5. Hybrid nanostructured films and surface morphology of ZnO films. A promising ELD approach has been exploited for Electrodeposition of various hybrid materials based on preparation of macroporous ZnO films [**73]. In this oxides or hydroxides of Zr, Ce, Gd, Fe, Ni, Cr, Y, Cu, Co, method highly ordered macroporous ZnO films were La and charged or neutral polymers was recently reported electrodeposited using polystyrene colloidal crystals as [*81,**82]. It was shown that composition, nanostructure templates. These results pave the way for formation of and morphology of the films could be tailored by variation advanced films combining photonic, luminescent and of bath compositions, deposition parameters and mass piezoelectric properties. Similar strategies might be used transport conditions for organic and inorganic components. for a number of other photonic crystals. The microstructure of an optimized hybrid ceria–PDDA/ zirconia–PDDA laminate film on a graphite substrate, 3 .3. High-temperature coatings and solid oxide fuel cells prepared by method developed in Ref. [*81], is shown in Fig. 4. The results obtained are significant for electrodepoImportant developments were reported in the field of sition of hybrid thick films. These nanocomposites not electrodeposition of materials for high temperature applica- only combine the advantageous properties of organic and tions. Advanced ceramic coatings were deposited for inorganic components but also exhibit novel properties
A.R. Boccaccini, 1. Zhitomirsky/ Current Opinion in Solid State and Materials Science 6(2002)251-260 257 4. Conclusions EPD and ELD are very versatile and cost-effective eramic processing techniques. The last 2 years have seen a significant increment of the applications areas where EPD and eld are used with substantial technical advan- tages, which can lead to commercial success and large- F Probably one of the most promising areas of applica- tions of both EPD and ELD is in SOFC manufacturing, as the increasing number of related publications and patents show. Specific areas where the use of EPD is expected to increase are: fabrication of ceramic matrix composites, functionally graded materials, laminated ceramics and 15akU586E31337/88 cluding dielectric, superconducting, semiconducting and bioactive coatings. The synthesis of ceramic nano-struc Fig 4. SEM micrograph of an advanced hybrid ceria-PDDA/zirconia- tures may become another area where EPD will show PDDA laminate film(F)on a graphite substrate(S)prepared by ELd advantages over other techniques, as the (limited)work following the method developed in Ref [81] carried out so far indicates. In the mentioned application areas. epd has significant industrial relevance and com- mercial advantage over other fabrication routes, as it can be readily scaled up using inexpensive equipment which cannot be attained with single-phase materials ELD is increasingly being used for preparation of Important applications of the hybrid films were discussed nanostructured thin films for various applications. This in Refs.[*82,12] technique provides many new possibilities in design of novel materials and devices. Important directions for future development include electrode materials, ferroelectric and 3.6. Other applications magnetic films, hybrid films, photonic crystals, and materi- Electrolytic deposition is being extensively studied for It is also recognized that further research efforts in the the preparation of copper oxide thin films [831 field of analytical and numerical modeling of the EPD and Substantial progress has also been made in electro- ELD processes are mandatory, in order to change the chemical preparation of MnO, films [84] Special atten- empirical, non-satisfactory time consuming trial-and-error tion has been paid to the influence of microstructure on approach which has dominated the experimental work and electrochemical properties of manganese oxide films technological developments in the area so far [85, 86]. Possible deposition mechanisms have been pro- posed and the electrochromic properties of the films have been described [ 86] Acknowledgements Electrodeposition has created important opportunities in preparation of thin films for catalytic applications. A novel ARB acknowledges financial support from the Nuffield electrochemical route for preparation of composite Pb and Foundation( London, UK) Co oxide films has been reported by Cattarin et al. [87].It is significant that the composites exhibited much higher catalytic activity compared to similar materials prepared by other electrochemical methods References Of particular importance is the recently demonstrated lity of electrochemical metal oxide photopatterning on Papers of particular interest, published within the annual n-and p-type silicon. Choi and Buriak [**88] developed period of review, have been highlighted as bipolar electrochemical techniques for patterning of silicon of special interest; illuminated through a photomask. The authors pro ** of outstanding interest deposition mechanisms and applied the techniques for Zno, CeO2 and Cr2O3. The ability to perform electrodepo- [1] Gani MSJ. Electrophoretic deposition. A review. Ind Ceram 994:14:163-74 sition on specific, localized areas of substrates is important (*2] Sarkar P, Nicholson PS. Electrophoretic deposition(EPD): Mecha- for fabrication of various electronic devices and in nisms, kinetics, and application to ceramics. J Am Ceram Soc 996, 79: 1987-2002, Excellent comprehensive review, covering
A.R. Boccaccini, I. Zhitomirsky / Current Opinion in Solid State and Materials Science 6 (2002) 251–260 257 4. Conclusions EPD and ELD are very versatile and cost-effective ceramic processing techniques. The last 2 years have seen a significant increment of the applications areas where EPD and ELD are used with substantial technical advantages, which can lead to commercial success and largescale production. Probably one of the most promising areas of applications of both EPD and ELD is in SOFC manufacturing, as the increasing number of related publications and patents show. Specific areas where the use of EPD is expected to increase are: fabrication of ceramic matrix composites, functionally graded materials, laminated ceramics and coatings for tribological and functional applications, including dielectric, superconducting, semiconducting and bioactive coatings. The synthesis of ceramic nano-strucFig. 4. SEM micrograph of an advanced hybrid ceria–PDDA/zirconia– tures may become another area where EPD will show PDDA laminate film (F) on a graphite substrate (S) prepared by ELD advantages over other techniques, as the (limited) work following the method developed in Ref. [*81]. carried out so far indicates. In the mentioned application areas, EPD has significant industrial relevance and commercial advantage over other fabrication routes, as it can be readily scaled up using inexpensive equipment. which cannot be attained with single-phase materials. ELD is increasingly being used for preparation of Important applications of the hybrid films were discussed nanostructured thin films for various applications. This in Refs. [**82,12]. technique provides many new possibilities in design of novel materials and devices. Important directions for future development include electrode materials, ferroelectric and 3 .6. Other applications magnetic films, hybrid films, photonic crystals, and materials for capacitors. Electrolytic deposition is being extensively studied for It is also recognized that further research efforts in the the preparation of copper oxide thin films [*83]. field of analytical and numerical modeling of the EPD and Substantial progress has also been made in electro- ELD processes are mandatory, in order to change the chemical preparation of MnO films [*84]. Special atten- empirical, non-satisfactory time consuming trial-and-error 2 tion has been paid to the influence of microstructure on approach which has dominated the experimental work and electrochemical properties of manganese oxide films technological developments in the area so far. [85,*86]. Possible deposition mechanisms have been proposed and the electrochromic properties of the films have been described [*86]. Acknowledgements Electrodeposition has created important opportunities in preparation of thin films for catalytic applications. A novel ARB acknowledges financial support from the Nuffield electrochemical route for preparation of composite Pb and Foundation (London, UK). Co oxide films has been reported by Cattarin et al. [87]. It is significant that the composites exhibited much higher catalytic activity compared to similar materials prepared by References other electrochemical methods. Of particular importance is the recently demonstrated Papers of particular interest, published within the annual ability of electrochemical metal oxide photopatterning on period of review, have been highlighted as: n- and p-type silicon. Choi and Buriak [**88] developed * of special interest; bipolar electrochemical techniques for patterning of silicon ** of outstanding interest. illuminated through a photomask. The authors proposed deposition mechanisms and applied the techniques for [1] Gani MSJ. Electrophoretic deposition. A review. Ind Ceram ZnO, CeO and Cr O . The ability to perform electrodepo- 2 23 1994;14:163–74. sition on specific, localized areas of substrates is important [**2] Sarkar P, Nicholson PS. Electrophoretic deposition (EPD): Mechafor fabrication of various electronic devices and in nisms, kinetics, and application to ceramics. J Am Ceram Soc nanotechnology. 1996;79:1987–2002, Excellent comprehensive review, covering
258 A.R. Boccaccini, 1. Zhitomirsky/ Current Opinion in Solid State and Materials Science 6(2002)251-260 both fundamental aspects of the EPD process as well as applications [18 Ishihara T, Shimose K, Kudo T, Nishiguchi H, Akbay T, Takita Y. Preparation of yttria-stabilised zirconia thin films on strontium- [*3] Van der Biest O, Vandeperre LJ. Electrophoretic deposition of oped LaMnO3 cathode substrates via electrophoretic deposition for materials. Annu Rey Mater Sci 1999- 29- 327-52. Another com- id oxide fuel cells. J Am Ceram Soc 2000: 83- 1921-7 rehensive review on EPD, focusing on applications, mechanisms [19 Zhitomirsky I, Petric A. Electrophoretic deposition of ceramic and kinetics of the process aterials for fuel cell applications. J Eur Ceram Soc 2000 20: 2055- [+4] Therese GHA, Kamath PV. Electrochemical synthesis of metal xides and hydroxides. Chem Mater 2000, 12: 1195-204, Develop- [20 Wang Z, Shemilt J, Xiao P. Novel fabrication technique for the ments in electrolytic deposition before 2000 production of ceramic/ceramic and metal/ ceramic composite coat 5] Solomentsev Y, Guelcher SA, Bevan M, Anderson JL. Aggregation ngs. Scripta Mater 2000: 42: 653-9 dynamics for two particles during electrophoretic deposition under [21 Shrestha NK, Sakurada K, Masuko M, Saji T. Composite coatings steady fields. Langmuir 2000: 16: 9208-16, The authors develop of nickel and separation between two deposited particles during EPDy of Coatings 2001: 140: 175-81. A combination of EPD and ELD techniques is developed to produce wear resistant BN and Al2 O, [6]Sides PJ. Electrodynamically particle aggregation on an electrode reinforced Ni matrix coatings on iron substrates driven by an alternating electric field normal to it. [22] Wang Z, Shemilt J, Xiao P. Fabrication of ceramic composite 2001: 17: 5791-800, A model for the velocity due coatings using electrophoretic deposition, reaction bonding and low trohydrodynamic flow of electrolyte in the vicinity of a temperature sintering. J Eur Ceram Soc 2002: 22: 183-9, Novel sphere near an electrode. rocessing techniques based on EPD and ceramic reaction bonding [7 Guelcher SA, Solomentsev Y, Anderson JL. Aggregation of pairs of are presented, which lead to low-temperature densification of particles on electrodes during electrophoretic deposition. Powder ceramic composite coatings on metal substrates. Technol 2000, 110: 90-7, Experimental verification of the electro- [23] Lessing PA, Erickson Aw, Kunerth DC. Electrophoretic deposition kinetic (electroosmotic)model for the aggregation of particles on an (EPD) applied to reaction joining of silicon carbide and silicon nitride ceramics. J Mater Sci 2000: 35: 2913-25, EPD is used to [8] Perez AT, Saville D, Soria C. Modeling the electrophoretic apply ceramic interlayers for reaction joining silicon carbide and tion of colloidal particles. Europhys Lett 2001: 55: 425-31 silicon nitride ceramic parts cal simulations of the buildup of a layer of colloidal particles on an [24 Zhang J, Lee Bl. Electrophoretic deposition and characterisation of electrode micrometer-scale BaTio, based X7R dielectric thick films. J Am f9 Greil P, Cordelair J, Bezold A. Discrete element simulation Ceram Soc 2000: 83: 2417-2 ceramic powder processing. Z Metallk 2001; 92: 682-9, Presents [ 25] Hossein-Babaei F, Taghibakhsh F. Electrophoretically deposited numerical simulation of the EPD proces zinc oxide thick film gas sensor. Electron Lett 2000: 36: 1815-6 [*10 Sarkar P, De D, Yamashita K, Nicholson PS, Umegaki T Mimicking [26 Peng ZY, Liu ML. Preparation of dense platinum-yttria stabilised manometer atomic processes on a micrometer scale via electro- zirconia and yttria stabilised zirco deposition. J Am Ceram Soc 2000, 83: 1399-401, The La, gSr,, MnO, (LSM) substrates. J Am Ceram Soc 2001; 84: 283-8 f nucleation and growth of a silica monolayer during EPD [27] Ngo E, Joshi PC, Cole MW, Hubbard CW. Electrophoretic deposi- compared with that of atomic film growth via molecular-beam ion of pure and MgO-modified Ba.sSro4TiO, thick films for epitaxy. Striking similarities between both processes are found tunable microwave devices. Appl Phys Lett 2001: 79: 248-50 [11] Ferrari B, Farinas JC, Moreno R. Determination and control of [28]Kanamura K, Goto A, Rho YO, Umegaki T. Electrophoretic fabrication of LiCoO, positive electrodes for rechargeable lithium phoretic deposition. J Am Ceram Soc 2001: 84: 733-9, Galvanic batteries. J Power Sources 2001: 97-98: 294-7 reactions in electrodes during EPD from aqueous suspensions ar [ Jeon BS, Hong KY, Yoo JS, Whang Kw. Studies in the phosphor investigated reen prepared by electrophoretic deposition for plasma displa [12 Zhitomirsky I, Petric A. The electrode of ceramic and nel applications. J Electrochem Soc 2000; 147: 4356-62 rganoceramic films for fuel cells. JOM: The member journal of The [30] Hamagami J, Nakajima T, Kanamura K, Umegaki T. Electrophoretic fabrication and photocatalytic performance of TiO, /fluorocarbon polymer composite films. Key Eng Mater 2002: 216: 53- 31] Ferrari B, Moreno R, Sarkar P, Nicholson PS. Electrophoretic lectrochem Soc 2000, 147: 1682-7, Excellent summary on the deposition of Mgo from organic suspensions. J Eur Ceram Soc application of EPD to SOFC materials, focusing on small tubular 2000,20:99-10 cathode substrates and cathode/electrolyte/anode multila 32 Hossein-Babaei F, Raissidehkordi B. Electrophoretic deposition of [14 Chen F, Liu M. Preparati ttria-stabilised zirconia(YSZ)films Ago thick films from an acetone suspension. J Eur Ceram Soc on Lao.gs Sros MnO,(LSM) and LSM-YSZ substrates using an 200020:2165-8 electrophoretic deposition (EPD) process. J Eur Ceram So 33] Kawachi M, Sato N, Suzuki E, Ogawa S, Noto K, Yoshizawa M. 2001;21:127-34 Fabrication of YBa, Cu, Os films by electrophoretic depositio [15 Matthews T, Rabu N, Sellar JR, Muddle BC technique. Physica C 2001- 357-360: 1023-6 a, -Sr, Ga,-,Mg, O, -fs +r/ thin films by electroph 1*34 Ochsenkuehn-Petropoulou M, Argyropoulou R, Tarantilis P, Vottea I, tion and its conductivity measurement. Solid Dchsenkuehn KM. Parissakis G. Large area YBaCuO and BScco 000,128:111-5 coatings produced on different substrates by an electrophoretic [16] Will J, Hrushka MKM, Gubler L, Gauckler LJ. Electrophoretic deposition technique. J Mater Proc Technol 2001: 108: 179-8 deposition of zirconia and porous anodic substrates. J Am Ceram 35] De Sena LA, De Andrade MC, Rossi AM, Soares GD. Hydroxy Soc2001;84:328-32. apatite deposition by electrophoresis on titanium sheets with differ- [17 Basu RN, Randall CA, Mayo M. Fabrication of dense zirconia ent surface finishing. J Biomed Mater Res 2002: 60: 1-7. electrolyte films for tubular solid oxide fuel cells by electrophoretic 36 Nie X, Leyland A, Matthews A, Jiang JC, Meletis El. Effects of deposition. J Am Ceram Soc 2001; 84: 33-40, The authors present a olution pH and electrical parameters on hydroxyapatite coatings novel approach for obtaining high-density, adherent zirconia films posited by a plasma-assisted electrophoresis technique. J Biomed on porous, doped lanthanum manganite cathode tubes which in- Mater res2001;57:612-8 volves using a thin fugitive carbon interphase 37 Boccaccini AR, Krueger HG, Schindler U. Ceramic coatings
258 A.R. Boccaccini, I. Zhitomirsky / Current Opinion in Solid State and Materials Science 6 (2002) 251–260 both fundamental aspects of the EPD process as well as applications [18] Ishihara T, Shimose K, Kudo T, Nishiguchi H, Akbay T, Takita Y. to ceramic technology. Preparation of yttria-stabilised zirconia thin films on strontium- [**3] Van der Biest O, Vandeperre LJ. Electrophoretic deposition of doped LaMnO3 cathode substrates via electrophoretic deposition for materials. Annu Rev Mater Sci 1999;29:327–52, Another com- solid oxide fuel cells. J Am Ceram Soc 2000;83:1921–7. prehensive review on EPD, focusing on applications, mechanisms [19] Zhitomirsky I, Petric A. Electrophoretic deposition of ceramic and kinetics of the process. materials for fuel cell applications. J Eur Ceram Soc 2000;20:2055– [**4] Therese GHA, Kamath PV. Electrochemical synthesis of metal 61. oxides and hydroxides. Chem Mater 2000;12:1195–204, Develop- [20] Wang Z, Shemilt J, Xiao P. Novel fabrication technique for the ments in electrolytic deposition before 2000. production of ceramic/ceramic and metal/ceramic composite coat- [5] Solomentsev Y, Guelcher SA, Bevan M, Anderson JL. Aggregation ings. Scripta Mater 2000;42:653–9. dynamics for two particles during electrophoretic deposition under [*21] Shrestha NK, Sakurada K, Masuko M, Saji T. Composite coatings steady fields. Langmuir 2000;16:9208–16, The authors develop a of nickel and ceramic particles prepared in two steps. Surface mathematical model for the time evolution of the probability of Coatings 2001;140:175–81, A combination of EPD and ELD separation between two deposited particles during EPD. techniques is developed to produce wear resistant BN and Al O2 3 [6] Sides PJ. Electrodynamically particle aggregation on an electrode reinforced Ni matrix coatings on iron substrates. driven by an alternating electric field normal to it. Langmuir [*22] Wang Z, Shemilt J, Xiao P. Fabrication of ceramic composite 2001;17:5791–800, A model for the velocity due to elec- coatings using electrophoretic deposition, reaction bonding and low trohydrodynamic flow of electrolyte in the vicinity of a dielectric temperature sintering. J Eur Ceram Soc 2002;22:183–9, Novel sphere near an electrode. processing techniques based on EPD and ceramic reaction bonding [7] Guelcher SA, Solomentsev Y, Anderson JL. Aggregation of pairs of are presented, which lead to low-temperature densification of particles on electrodes during electrophoretic deposition. Powder ceramic composite coatings on metal substrates. Technol 2000;110:90–7, Experimental verification of the electro- [*23] Lessing PA, Erickson AW, Kunerth DC. Electrophoretic deposition kinetic (electroosmotic) model for the aggregation of particles on an (EPD) applied to reaction joining of silicon carbide and silicon electrode. nitride ceramics. J Mater Sci 2000;35:2913–25, EPD is used to [8] Perez AT, Saville D, Soria C. Modeling the electrophoretic deposi- apply ceramic interlayers for reaction joining silicon carbide and tion of colloidal particles. Europhys Lett 2001;55:425–31, Numeri- silicon nitride ceramic parts. cal simulations of the buildup of a layer of colloidal particles on an [24] Zhang J, Lee BI. Electrophoretic deposition and characterisation of electrode. micrometer-scale BaTiO based X7R dielectric thick films. J Am 3 [*9] Greil P, Cordelair J, Bezold A. Discrete element simulation of Ceram Soc 2000;83:2417–22. ceramic powder processing. Z Metallk 2001;92:682–9, Presents a [25] Hossein-Babaei F, Taghibakhsh F. Electrophoretically deposited numerical simulation of the EPD process. zinc oxide thick film gas sensor. Electron Lett 2000;36:1815–6. [**10] Sarkar P, De D, Yamashita K, Nicholson PS, Umegaki T. Mimicking [26] Peng ZY, Liu ML. Preparation of dense platinum-yttria stabilised nanometer atomic processes on a micrometer scale via electro- zirconia and yttria stabilised zirconia films on porous phoretic deposition. J Am Ceram Soc 2000;83:1399–401, The La Sr MnO (LSM) substrates. J Am Ceram Soc 2001;84:283–8. 0.9 0.1 3 process of nucleation and growth of a silica monolayer during EPD [27] Ngo E, Joshi PC, Cole MW, Hubbard CW. Electrophoretic deposiis compared with that of atomic film growth via molecular-beam tion of pure and MgO-modified Ba Sr TiO thick films for 0.6 0.4 3 epitaxy. Striking similarities between both processes are found. tunable microwave devices. Appl Phys Lett 2001;79:248–50. [11] Ferrari B, Farinas JC, Moreno R. Determination and control of [28] Kanamura K, Goto A, Rho YO, Umegaki T. Electrophoretic metallic impurities in alumina deposits obtained by aqueous electro- fabrication of LiCoO positive electrodes for rechargeable lithium 2 phoretic deposition. J Am Ceram Soc 2001;84:733–9, Galvanic batteries. J Power Sources 2001;97–98:294–7. reactions in electrodes during EPD from aqueous suspensions are [29] Jeon BS, Hong KY, Yoo JS, Whang KW. Studies in the phosphor investigated. screen prepared by electrophoretic deposition for plasma display [12] Zhitomirsky I, Petric A. The electrodeposition of ceramic and panel applications. J Electrochem Soc 2000;147:4356–62. organoceramic films for fuel cells. JOM: The member journal of The [30] Hamagami J, Nakajima T, Kanamura K, Umegaki T. Electrophoretic Minerals, Metals & Materials Society 2001;53:48–50. fabrication and photocatalytic performance of TiO /fluorocarbon 2 [**13] Negishi H, Sakai N, Yamaji K, Horita T, Yokokawa H. Application polymer composite films. Key Eng Mater 2002;216:53–6. of electrophoretic deposition technique to solid oxide fuel cells. J [31] Ferrari B, Moreno R, Sarkar P, Nicholson PS. Electrophoretic Electrochem Soc 2000;147:1682–7, Excellent summary on the deposition of MgO from organic suspensions. J Eur Ceram Soc application of EPD to SOFC materials, focusing on small tubular 2000;20:99–106. cathode substrates and cathode/electrolyte/anode multilayers. [32] Hossein-Babaei F, Raissidehkordi B. Electrophoretic deposition of [14] Chen F, Liu M. Preparation of yttria-stabilised zirconia (YSZ) films MgO thick films from an acetone suspension. J Eur Ceram Soc on La Sr MnO (LSM) and LSM-YSZ substrates using an 2000;20:2165–8. 0.85 0.15 3 electrophoretic deposition (EPD) process. J Eur Ceram Soc [33] Kawachi M, Sato N, Suzuki E, Ogawa S, Noto K, Yoshizawa M. 2001;21:127–34. Fabrication of YBa Cu O films by electrophoretic deposition 2 48 [15] Matthews T, Rabu N, Sellar JR, Muddle BC. Fabrication of technique. Physica C 2001;357–360:1023–6. La Sr Ga Mg O thin films by electrophoretic deposi- [**34] Ochsenkuehn-Petropoulou M, Argyropoulou R, Tarantilis P,Vottea I, 12x x 12y y 32(x1y)/2 tion and its conductivity measurement. Solid State Ionics Ochsenkuehn KM, Parissakis G. Large area YBaCuO and BSCCO 2000;128:111–5. coatings produced on different substrates by an electrophoretic [16] Will J, Hrushka MKM, Gubler L, Gauckler LJ. Electrophoretic deposition technique. J Mater Proc Technol 2001;108:179–84. deposition of zirconia and porous anodic substrates. J Am Ceram [35] De Sena LA, De Andrade MC, Rossi AM, Soares GD. HydroxySoc 2001;84:328–32. apatite deposition by electrophoresis on titanium sheets with differ- [*17] Basu RN, Randall CA, Mayo MJ. Fabrication of dense zirconia ent surface finishing. J Biomed Mater Res 2002;60:1–7. electrolyte films for tubular solid oxide fuel cells by electrophoretic [36] Nie X, Leyland A, Matthews A, Jiang JC, Meletis EI. Effects of deposition. J Am Ceram Soc 2001;84:33–40, The authors present a solution pH and electrical parameters on hydroxyapatite coatings novel approach for obtaining high-density, adherent zirconia films deposited by a plasma-assisted electrophoresis technique. J Biomed on porous, doped lanthanum manganite cathode tubes which in- Mater Res 2001;57:612–8. volves using a thin fugitive carbon interphase. [37] Boccaccini AR, Krueger HG, Schindler U. Ceramic coatings on
A.R. Boccaccini, 1. Zhitomirsky/ Current Opinion in Solid State and Materials Science 6(2002)251-260 carbon and metallic fibres by electrophoretic deposition. Mater Le 57 Uchikoshi T, Ozawa K, Hatton BD, Sakka Y. Dense, bubble-free 2001;51:225-30 [38 Zhitomirsky I. Electrophoretic hydroxyapatite coatings and fibres. deposition. J Mater Res 2001: 16: 321-4 Mater Lett 2000, 42: 262-71, Hollow hydroxyapatite fibres of differ- [*58] Limmer SJ, Seraji S, Wu Y, Chou TP, Nguyen C, Cao G. Template- ent diameters are fabricated based growth of various oxide nanorods by sol-gel electrophoresis B9] Su B, Ponton CB, Button Tw. Hydrothermal and electrophore Adv Funct Mater 2002: 12: 59-64, This is a pioneering work deposition of lead zirconate titanate(PZT) films. J Eur Ceram Soc showing the fabrication of ceramic nanorods of controlled length 2001;21:153942. and diameter by sol-gel EPD [40] Seike T, Matsuda M, Miyake M. Preparation of FAU type zeolite [59]Limmer SJ, Seraji S, Forbess M, Wu Y, Chou TP, Nguyen C, Cao membranes by electrophoretic deposition and their separation prop- G. Electrophoretic growth of lead zirconate titanate nanorods. Adv erties. J Mater Chem 2002: 12- 366-8. Mater2001;13:1269-72. (41] Chen CY, Chen SY, Liu DM. Electrophoretic deposition forming of [60] Gao B, Yue GZ, Qiu Q, Cheng Y, Shimoda H, Fleming L, Zhou O porous alumina membranes. Acta Mater 1999, 47: 2717-26 abrication and electron field emission properties of carbon 42 Ke C, Yang WL, Ni Z, Wang Y, Tang Y, Gu Y, Gao Z. Electro nanotube films by electrophoretic deposition. Adv Mate phoretic assembly of nanozeolites: zeolite coated fibres and hollow 2001:13:1770-3 zeolite fibres. Chem Commun 2001: 8: 783-4 [61 Affoune AM, Prasad BLV, Sato H, Enoki T. Electrophoretic 143Ahlers CB, Talbot JB. Voltammetric behaviour of ze deposition of nanosized diamond particles. Langmuir 2001; 17: 547- electrodes fabricated by electrophoretic deposition. Acta 2000: 45: 3379-87. Zeolite-modified electrodes [62] Smeets K, Tabellion J, Clasen R. Modification of green bodies by EPD are tested for applications in electroanalysis and electro- incorporating nanosized particles via electrophoretic deposition catalysis (EPD). Key Eng Mater2002206-213:2069-72. 1*44 Boccaccini AR, Kaya C, Chawla KK. Use of electrophoretic 63 Subramanian V, Wolf E, Kamat PV. Semiconductor-metal composite deposition in the processing of fibre reinforced ceramic and glass nanostructures. To what extent do metal nanoparticles improve the natrix composites: a review. Composites A 2001: 32: 997-1006, photocatalytic activity of TiO, films? J Phys Chem B Comprehensive review on the application of EPD to fabricate fibre 2001;105:11439-46 reinforced ceramic matrix composites covering a great variety of [*64 Zhitomirsky I. New developments in electrolytic deposition matrices and fibres ramic films. Bull Am Ceram Soc 2000: 79: 57-63.A mechanism 445] Kaya C, Kaya F, Boccaccini AR, Chawla KK. Fabrication and cathodic electrolytic deposition posed based on the DLvo racterisation of Ni-coated carbon fibre-reinforced alumin theory. Various electrochemical strategies for deposition of ceramic ceramic matrix composites using electrophoretic deposition. Acta aterials are discusse Mater2001;49:l189-97 165 Zhitomirsky I. Cathodic electrodeposition of ceramic and 46] Kaya C, Boccaccini AR, Chawla KK. Electrophoretic deposition ganoceramic materials Fundamental aspects. Adv Colloid Interface forming of Ni-coated carbon fibre-reinforced borosilicate glass Sci 2002: 97: 277-315, A comprehensive review paper covering matrix composites. J Am Ceram Soc 2000: 83: 1885-8 undamental aspects of cathodic electrolytic and electrophoretic 47 Moritz K, Mueller E. Electrophoretic infiltration of woven carbon deposition fibre mats with SiC powder suspensions. Key Eng Mater 2002: 206- [66] Shibata N. maeda m. fabrication of barium titanate thin 213:193-6. by potentiostatic electrochemical deposition, J Ceram Soc Jp 48 Manocha LM, Panchal C, Manocha S. Silica/silica 1: 109: 915-9, A new technique for electrodeposition of BaTio through electrophoretic infiltration. Effect of processing conditions Ims on platinized silicon is developed based on the use of on densification of composites. Sci Eng Comp Mater 2000: 9: 21 oxocomplexes of Ti(IV). The BaTio, films were crystallized at relatively low temperatures 449]Timms LA, Westby W, Prentice C, Jaglin D, Shatwell RA, Binner [67] Ishikawa Y, Matsumoto Y. Electrodeposition of TiO, photocataly JGP Reducing chemical vapour infiltration time for ceramic mat ito nano-pores of hard alumite. Electrochim Acta 2001: 46: 2819- composites. J Microsc Oxford 2001- 201:-316-23 150 Kaya C, Boccaccini AR. Colloidal processing of complex [68] Zhang x, Yao B, Zhao L, Liang C, Zhang L, Mao Y. Electro stainless steel woven fiber mat reinforced alumina ceramic chemical fabrication of single-crystalline anatase TiO,nanowire composites using electrophoretic deposition. J Mater Sci arrays. J Electrochem Soc 2001; 148: G398-400 2001: 20: 1465-7, For the first time fibre-reinforced alumin 1*69 Pauporte T, Lincot D. Electrodeposition of semiconductors for composites of tubular shape are fabricated by EPD optoelectronic devices: results on zinc oxide. Electrochim Acta 51]Kooner S, Westby WS, Watson CMA, Farries PM. Processing of 2000,45:3345-53,An ortant paper, which describes epitaxial Nextel 720/mullite composition. Composite using electrophoretic growth of zinc oxide films on single crystal GaN layers. Optical and deposition. J Eur Ceram Soc 2000: 20: 631-8 luminescence properties of the films were studied 52 Put S, Vleugels J, Van der Biest O. Functionally graded wC-Co 70 Liu R, Vertegel AA, Bohannan EW, Sorenson TA, Switzer JA. materials produced by electrophoretic deposition. Scripta Mater Epitaxial electrodeposition of zinc oxide nanopillars on single- 200145:1139-45 crystal gold. Chem Mater 2001; 13: 508-12, Epitaxial electrodeposi- 53]Put S, Anne G, Vleugels J, Van der Biest O. Functionally graded tion of Zno onto Au( ll1), Au( 110) and Au( 100) single crystal ZrO2-wC composites processed by electrophoretic deposition. Key substrates is described. The electrodeposited nanopillars can be used Eng Mater2002,206-213:189-9 for advanced electronic devices [54] Zhao C, Vandeperre L, Vleugels J, Van der Biest O. Cylindrica [71] Pauporte T, Lincot D. Hydrogen peroxide oxygen precursor for zinc Al, O, /TZP functionally graded materials by EPD. Br Ceram Tr oxide, I. Deposition in perchlorate medium. J Electrochem Soc 2000: 99 284-7, First report on fabrication of cylindrical FGM by 2001: 148: C310-4, Advanced electrochemical technique has been developed for electrodeposition of Zno films. 55] Hatton B, Nicholson PS. Design and fracture of layered Al, O, [72] Karuppuchamy S, Yoshida T, Sugiura T, Minoura H. Self-assembly TZ3Y composites produced by electrophoretic deposition. J Am of Zno/riboflavin 5-phosphate thin films by one-step electrodeposi- eram Soc2001;84:571-6 ion and its characterization. Thin Solid Films 2001: 397: 63-9. 56] Moreno R, Ferrari B. Advanced ceramics via EPD of aqueous [*73 Sumida T, Wada Y, Kitamura T, Yanagida S Macroporous Zno slurries. Ceram Bull 2000: 79: 44-8 films electrochemically prepared by templating of opal films, Chem
A.R. Boccaccini, I. Zhitomirsky / Current Opinion in Solid State and Materials Science 6 (2002) 251–260 259 carbon and metallic fibres by electrophoretic deposition. Mater Lett [57] Uchikoshi T, Ozawa K, Hatton BD, Sakka Y. Dense, bubble-free 2001;51:225–30. ceramic deposits from aqueous suspensions by electrophoretic [*38] Zhitomirsky I. Electrophoretic hydroxyapatite coatings and fibres. deposition. J Mater Res 2001;16:321–4. Mater Lett 2000;42:262–71, Hollow hydroxyapatite fibres of differ- [**58] Limmer SJ, Seraji S, Wu Y, Chou TP, Nguyen C, Cao G. Templateent diameters are fabricated. based growth of various oxide nanorods by sol–gel electrophoresis. [39] Su B, Ponton CB, Button TW. Hydrothermal and electrophoretic Adv Funct Mater 2002;12:59–64, This is a pioneering work deposition of lead zirconate titanate (PZT) films. J Eur Ceram Soc showing the fabrication of ceramic nanorods of controlled length 2001;21:1539–42. and diameter by sol–gel EPD. [40] Seike T, Matsuda M, Miyake M. Preparation of FAU type zeolite [*59] Limmer SJ, Seraji S, Forbess MJ, Wu Y, Chou TP, Nguyen C, Cao membranes by electrophoretic deposition and their separation prop- G. Electrophoretic growth of lead zirconate titanate nanorods. Adv erties. J Mater Chem 2002;12:366–8. Mater 2001;13:1269–72. [41] Chen CY, Chen SY, Liu DM. Electrophoretic deposition forming of [*60] Gao B, Yue GZ, Qiu Q, Cheng Y, Shimoda H, Fleming L, Zhou O. porous alumina membranes. Acta Mater 1999;47:2717–26. Fabrication and electron field emission properties of carbon [42] Ke C, Yang WL, Ni Z, Wang YJ, Tang Y, Gu Y, Gao Z. Electro- nanotube films by electrophoretic deposition. Adv Mater phoretic assembly of nanozeolites: zeolite coated fibres and hollow 2001;13:1770–3. zeolite fibres. Chem Commun 2001;8:783–4. [61] Affoune AM, Prasad BLV, Sato H, Enoki T. Electrophoretic [*43] Ahlers CB, Talbot JB. Voltammetric behaviour of zeolite-modified deposition of nanosized diamond particles. Langmuir 2001;17:547– electrodes fabricated by electrophoretic deposition. Electrochim 51. Acta 2000;45:3379–87, Zeolite-modified electrodes fabricated by [62] Smeets K, Tabellion J, Clasen R. Modification of green bodies by EPD are tested for applications in electroanalysis and electro- incorporating nanosized particles via electrophoretic deposition catalysis. (EPD). Key Eng Mater 2002;206–213:2069–72. [**44] Boccaccini AR, Kaya C, Chawla KK. Use of electrophoretic [63] Subramanian V, Wolf E, Kamat PV. Semiconductor-metal composite deposition in the processing of fibre reinforced ceramic and glass nanostructures. To what extent do metal nanoparticles improve the matrix composites: a review. Composites A 2001;32:997–1006, photocatalytic activity of TiO films? J Phys Chem B 2 Comprehensive review on the application of EPD to fabricate fibre 2001;105:11439–46. reinforced ceramic matrix composites covering a great variety of [**64] Zhitomirsky I. New developments in electrolytic deposition of matrices and fibres. ceramic films. Bull Am Ceram Soc 2000;79:57–63, A mechanism of [45] Kaya C, Kaya F, Boccaccini AR, Chawla KK. Fabrication and cathodic electrolytic deposition is proposed based on the DLVO characterisation of Ni-coated carbon fibre-reinforced alumina theory. Various electrochemical strategies for deposition of ceramic ceramic matrix composites using electrophoretic deposition. Acta materials are discussed. Mater 2001;49:1189–97. [*65] Zhitomirsky I. Cathodic electrodeposition of ceramic and or- [46] Kaya C, Boccaccini AR, Chawla KK. Electrophoretic deposition ganoceramic materials. Fundamental aspects. Adv Colloid Interface forming of Ni-coated carbon fibre-reinforced borosilicate glass Sci 2002;97:277–315, A comprehensive review paper covering matrix composites. J Am Ceram Soc 2000;83:1885–8. fundamental aspects of cathodic electrolytic and electrophoretic [47] Moritz K, Mueller E. Electrophoretic infiltration of woven carbon deposition. fibre mats with SiC powder suspensions. Key Eng Mater 2002;206– [*66] Nomura K, Shibata N, Maeda M. Fabrication of barium titanate thin 213:193–6. films by potentiostatic electrochemical deposition. J Ceram Soc Jpn [48] Manocha LM, Panchal C, Manocha S. Silica/silica composites 2001;109:915–9, A new technique for electrodeposition of BaTiO3 through electrophoretic infiltration. Effect of processing conditions films on platinized silicon is developed based on the use of on densification of composites. Sci Eng Comp Mater 2000;9:219– peroxocomplexes of Ti(IV). The BaTiO films were crystallized at 3 30. relatively low temperatures. [49] Timms LA, Westby W, Prentice C, Jaglin D, Shatwell RA, Binner [67] Ishikawa Y, Matsumoto Y. Electrodeposition of TiO photocatalyst 2 JGP. Reducing chemical vapour infiltration time for ceramic matrix into nano-pores of hard alumite. Electrochim Acta 2001;46:2819– composites. J Microsc Oxford 2001;201:316–23. 24. [*50] Kaya C, Boccaccini AR. Colloidal processing of complex shape [68] Zhang X, Yao B, Zhao L, Liang C, Zhang L, Mao Y. Electrostainless steel woven fiber mat reinforced alumina ceramic matrix chemical fabrication of single-crystalline anatase TiO nanowire 2 composites using electrophoretic deposition. J Mater Sci Lett arrays. J Electrochem Soc 2001;148:G398–400. 2001;20:1465–7, For the first time fibre-reinforced alumina matrix [**69] Pauporte T, Lincot D. Electrodeposition of semiconductors for composites of tubular shape are fabricated by EPD. optoelectronic devices: results on zinc oxide. Electrochim Acta [51] Kooner S, Westby WS, Watson CMA, Farries PM. Processing of 2000;45:3345–53, An important paper, which describes epitaxial Nextel 720/mullite composition. Composite using electrophoretic growth of zinc oxide films on single crystal GaN layers. Optical and deposition. J Eur Ceram Soc 2000;20:631–8. luminescence properties of the films were studied. [52] Put S, Vleugels J, Van der Biest O. Functionally graded WC–Co [*70] Liu R, Vertegel AA, Bohannan EW, Sorenson TA, Switzer JA. materials produced by electrophoretic deposition. Scripta Mater Epitaxial electrodeposition of zinc oxide nanopillars on single- 2001;45:1139–45. crystal gold. Chem Mater 2001;13:508–12, Epitaxial electrodeposi- [53] Put S, Anne G, Vleugels J, Van der Biest O. Functionally graded tion of ZnO onto Au(111), Au(110) and Au(100) single crystal ZrO -WC composites processed by electrophoretic deposition. Key substrates is described. The electrodeposited nanopillars can be used 2 Eng Mater 2002;206–213:189–92. for advanced electronic devices. [*54] Zhao C, Vandeperre L, Vleugels J, Van der Biest O. Cylindrical [*71] Pauporte T, Lincot D. Hydrogen peroxide oxygen precursor for zinc Al O /TZP functionally graded materials by EPD. Br Ceram Trans oxide. I. Deposition in perchlorate medium. J Electrochem Soc 2 3 2000;99:284–7, First report on fabrication of cylindrical FGM by 2001;148:C310–4, Advanced electrochemical technique has been EPD. developed for electrodeposition of ZnO films. [55] Hatton B, Nicholson PS. Design and fracture of layered Al O / [72] Karuppuchamy S, Yoshida T, Sugiura T, Minoura H. Self-assembly 2 3 TZ3Y composites produced by electrophoretic deposition. J Am of ZnO/riboflavin 59-phosphate thin films by one-step electrodeposiCeram Soc 2001;84:571–6. tion and its characterization. Thin Solid Films 2001;397:63–9. [56] Moreno R, Ferrari B. Advanced ceramics via EPD of aqueous [**73] Sumida T, Wada Y, Kitamura T, Yanagida S. Macroporous ZnO slurries. Ceram Bull 2000;79:44–8. films electrochemically prepared by templating of opal films, Chem
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