Application of design of experiment techniques in the two step pretreatment proses for diamond coating

Abstract

Chemical vapor Deposition (CVD) is one of diamond synthesis process and it is widely applied to cutting tools to enhance wear resistance and increase tool life. One of the methods of ensuring adhesion of diamond on the substrate is through the roughening and the substrate surface and the removal of cobalt at the substrate surface. This method is applied during the pretreatment method, which is before the coating process. In this study, Murakami etchant was used to roughen the surface and this is followed by an acid treatment to remove cobalt at the Tungsten Carbide (WC- 6% Co) surface. Concentration of both solutions has been varied. Design of Experiment Techniques has been used to determine the optimum combination of the factor that has been investigated. Result from this study shows the optimum condition for maximizing the surface roughness is 10.23g of potassium ferricyanide, 29.92g of potassium hydroxide and etching time in ultrasonic bath of 19.74 minutes while the optimum concentration for acid treatment is 60.36% for nitric acid, 10.29% of hydrogen peroxide and 89.43 seconds for etching time.