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)00080-3Current 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 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 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