Study on Electrophoretic Deposition Characteristics of Ultra-fine Diamond Powder

Diamond is a promising material especially applied in advanced machining tools, wear-resistant coatings, and the EPD technique should provide a simple method to develop hard coatings for precision machining tools or wear-resistant parts. Therefore, it is useful to research electrophoretic deposition characteristics of diamond powder itself, including the impact of adding ions on direction of EPD especially. In this paper, the effects of suspension concentration and applied voltage, deposition time, and added Ca2+ or Al3+ ions on electrophoretic characteristics of ultra-fine diamond powder were discussed, and electrophoretic deposition (EPD) parameters were optimized by a trial-and-error approach. The results show that smooth, uniform and dense coatings of diamond were obtained under suspension concentration of 1%-1.5% and applied voltage of 30-70 V. The thickness of diamond coating can be controlled by adjusting deposition time under constant voltage and suspension concentration. If deposition direction changed, the appropriate concentration of added Ca2+ and Al3+, respectively, is in the range of 0.005% to 0.01% and 0.05% to 0.10%.