Colloidal Film Formation Process Using Electrophoresis of Charged Particles in Liquid and Electrode Reaction

Electrophoresis of particles by applying an electric field to a colloidal suspension allows simultaneous manipulation and shaping of particles. A film forming process utilizing the electrophoretic phenomenon of charged particles in a liquid is called “electrophoretic deposition (EPD)” and is used for powder coating. The main difference between the EPD process and other colloidal processes is the coexistence of electrode reactions, ie electrochemical reactions that occur at the interface between the electrode and the electrolyte solution. The applied electric field in the EPD method plays an important role not only in the electrophoresis of charged particles but also in controlling the coagulation mechanism and film quality. This paper introduces the principle of the EPD process considering the electrode reaction and an example of the functional film formation process. ©2023 Japan Society of Powder and Powder Metallurgy.