| The composite coating is one of the methods of improving material which has an obvious effect on strengthening the surface of material, improving the performance of material and saving cost etc. The hard chromium coating has many advantages such as high hardness, low friction parameter, good performance of high temperature and oxidation resistance etc. By appending SiC particles in the electrolyte, composite coating can be prepared and it has better mechanic performance than hard chromium.In this paper, Cr/SiC composite coating was prepared by routine method firstly. The effect of temperature, concentration of SiC in electrolyte, speed of stirring and current density of cathode on composite quality of SiC in coating was studied. The result indicates the Cr/SiC composite coating can't be prepared by routine method.Next, cycle-commutate current was utilized to prepare Cr/SiC composite coating. The effect of etch time, temperature, concentration of SiC in electrolyte and additive on composite quality of SiC in coating, hardness, wear resistance, corrosion resistance of coating in 3.5% NaCl was studied. It is indicated that the etch technology was the decisive factor during the electroplating, the mini-crack was formed in etch and it facilitated the adulteration of SiC. When the temperature was at 50 degree centigrade, the concentration of SiC particle in electrolyte was 250g/L and the etch time was 5min, the composite coating could be prepared with the highest composite quality (4.9%), the wear resistance, hardness and corrosion resistance could also be on the top level. After the additive BL was entered, the number of mini-crack in the surface of coating increased obviously which result in the composite quality in coating increased and the wear resistance, hardness and wear resistance increased.
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