Ultra-low-electric power electrophoretic deposition by using non-flammable hydrofluoroether

A relative dielectric constant of a solvent is important for the electrophoretic deposition (EPD) suspension, and when the electrical resistance of the solvent is high, a large quantity of material is expected to be deposited. In this study, ethylperfluorobutylether (EFE), which is a kind of hydrofluoroether, was applied as the solvent for preparing a particle suspension for the EPD. EFE has the advantages of being polar, non-flammable, and having high electrical insulation properties. Silica powder was selected as the deposition material. When EFE is used, unlike when acetone-based EPD suspension was used, the amount deposited remains the same, but power consumption is 1/2,000 or less. Depending on conditions, power consumption is reducible even to 1/200,000. Thus, highly efficient EPD with ultra power saving ability was achieved. In addition, this process is extremely safe as EFE is non-flammable, removing the hazard of ignition. As the specific gravity of EFE is large, sedimentation of inorganic particles is slow; therefore, the dispersibility is excellent, and highly uniform coatings can be obtained. Unlike water-based EPD suspensions, the application of a high voltage is possible. In the present study, the deposition behavior was no different from that for conventional EPD, being controllable by varying the applied voltage, deposition time, and particle concentration.