Effect of current density on microstructure and microhardness of Ni-SiC coatings

Ni-SiC coatings were synthesized on the surface of compressor valves by using pulse electrodeposition method.The effect of current density on the content,microstructure and microhardness of the coatings was investigated by using the atomic absorption spectrophotometer,transmission electron microscope and microhardness tester.The results show that the SiC particle content in the coating increases first and then decreases with the increase of pulse current density.The current density was 7A/dm2,the coating has a density and fine structure,and SiC particles are evenly distributed in this coating.The current density was 7A/dm2,the microhardness of the coating reaches 842.9Hv.