L Besra, M. Liu Progress in Materials Science 52(2007)1-61 Table I Characteristics of electrodeposition techniques [2] Electroplating trophoretic depositis oving specie Solid particles Charge transfer on deposition Ion reduction Required conductance of liquid medium Preferred liquid b + Fig. 1. Schematic illustration of electrophoretic deposition process.(a) Cathodic EPD and (b) anodic EPD resistant and anti-oxidant ceramic coatings, fabrication of functional films for advanced microelectronic devices and solid oxide fuel cells as well as in the development of novel composites or bioactive coatings for medical implants, there has been increased interest for its application in nanoscale assembly for advanced functional materials [4]. Electropho- retic deposition also offers important advantages in the deposition of complex compounds nd ceramic laminates. The degree of stoichiometry in the electrophoretic deposit is con- trolled by the degree of stoichiometry in the powder used. According to Sarkar and Nich olson [5], particle/electrode reactions are not involved in EPD, and ceramic particles do not lose their charge on being deposited which can be shown from the observation that reversal of the electric field will strip of the deposited layer [6]. Therefore, it is important to use sim- ilarly charged particles and similar solvent-binder-dispersant systems for gaining better control of layer thickness. The principal driving force for electrophoretic deposition (EPD) is the charge on the particle and the electrophoretic mobility of the particles in the solvent under the influence of an applied electric field. The EPd technique has been used successfully for thick film of silica [7]. nanosize zeolite membrane [8] hydroxyapatite coating on metal substrate for biomedical applications [9, 10] luminescent materials [11- 13), high-Tc superconducting films [14, 15), gas diffusion electrodes and sensors [16, 17]. multi-layer composites [18] glass and ceramic matrix composites by infiltration of ceramic particles onto fibre fabrics [19], oxide nanorods[20], carbon nanotube film [21], functionally graded ceramics [22, 23], layered ceramics [24], superconductors [25, 26], piezoelectric mate- rials [27], etc. Indeed, the only intrinsic disadvantages of EPD, compared with other colloi dal processes(e.g. dip and slurry coating), is that it cannot use water as the liquid med because the application of a voltage to water causes the evolution of hydrogen and oxygen gases at the electrodes which could adversely affect the quality of the deposits formed. How- ever, given the numerous non-aqueous solvents that are available, this limitation is minorresistant and anti-oxidant ceramic coatings, fabrication of functional films for advanced microelectronic devices and solid oxide fuel cells as well as in the development of novel composites or bioactive coatings for medical implants, there has been increased interest for its application in nanoscale assembly for advanced functional materials [4]. Electropho￾retic deposition also offers important advantages in the deposition of complex compounds and ceramic laminates. The degree of stoichiometry in the electrophoretic deposit is con￾trolled by the degree of stoichiometry in the powder used. According to Sarkar and Nich￾olson [5], particle/electrode reactions are not involved in EPD, and ceramic particles do not lose their charge on being deposited which can be shown from the observation that reversal of the electric field will strip of the deposited layer [6]. Therefore, it is important to use sim￾ilarly charged particles and similar solvent–binder–dispersant systems for gaining better control of layer thickness. The principal driving force for electrophoretic deposition (EPD) is the charge on the particle and the electrophoretic mobility of the particles in the solvent under the influence of an applied electric field. The EPD technique has been used successfully for thick film of silica [7], nanosize zeolite membrane [8], hydroxyapatite coating on metal substrate for biomedical applications [9,10], luminescent materials [11– 13], high-Tc superconducting films [14,15], gas diffusion electrodes and sensors [16,17], multi-layer composites [18], glass and ceramic matrix composites by infiltration of ceramic particles onto fibre fabrics [19], oxide nanorods [20], carbon nanotube film [21], functionally graded ceramics [22,23], layered ceramics [24], superconductors [25,26], piezoelectric mate￾rials [27], etc. Indeed, the only intrinsic disadvantages of EPD, compared with other colloi￾dal processes (e.g. dip and slurry coating), is that it cannot use water as the liquid medium, because the application of a voltage to water causes the evolution of hydrogen and oxygen gases at the electrodes which could adversely affect the quality of the deposits formed. How￾ever, given the numerous non-aqueous solvents that are available, this limitation is minor. Table 1 Characteristics of electrodeposition techniques [2] Property Electroplating Electrophoretic deposition Moving species Ions Solid particles Charge transfer on deposition Ion reduction None Required conductance of liquid medium High Low Preferred liquid Water Organic Fig. 1. Schematic illustration of electrophoretic deposition process. (a) Cathodic EPD and (b) anodic EPD. 4 L. Besra, M. Liu / Progress in Materials Science 52 (2007) 1–61