Electrophoretic deposition process

The tape casting and electrophoretic deposition processes are amenable to scaleup, and thin electrolyte structures (0.25-0.5 mm) can be produced. The ohmic resistance of an electrolyte structure and the resulting ohmic polarization have a large influence on the operating voltage of MCFCs (14). FCE has stated that the electrolyte matrix encompasses 70% of the ohmic loss (15). At a current density of 160 mA/cm, the voltage drop (AVohm) of an 0.18 cm thick electrolyte structure, with a specific conductivity of -0.3 ohm cm at 650°C, was found to obey the relationship (13). 

Morikawa, H., Tsuihiji, N., Mitsui, T., and Kanamura, K. Preparation of membrane electrode assembly for fuel cells by using electrophoretic deposition process. Journal of the Electrochemical Society 2004 151 A1733-A1737. 

Figure 9.9. Schematic representation of the electrophoretic deposition process. (From ref (14) with permission of The American Ceramic Society)...

Schematic of electrophoretic deposition process. (From reference 22.)... 

Morikawa H, Tsuihiji N, Mitsui T, Kanamura K. Preparation of membrane eleetrode assembly for fuel cell by using electrophoretic deposition process. J Electrochem Soc 2004 151(10) A1733-7. 

On the other hand, it is only possible to electropaint conducting surfaces and, hence, the process is limited to a single coat. Also, the colour range is more restricted than with conventional painting. It should also be noted that electrolyte purification and conditioning is critical to the electrophoretic deposition process. Hence, ultrafiltration is widely applied to remove unwanted solids and microparticulates and to maintain electrolyte conductivity at a relatively low level. 

Owing to their low cost and environmental friendliness, aqueous electrolytes have been used predominantly in the electrocoating industry. Non-aqueous electrophoretic deposition processes have also been explored for use in the fabrication of electronic components and the production of ceramic coatings... 

Morikawa H, Tsuihiji N, Mitsui T and Kanamura K (2004) Preparation of Membrane Electrode Assembly for Fuel Cell by Using Electrophoretic Deposition Process, J. Electrochem. Soc., 151, pp. A1733-A1737. 

---