Effect of current density on microstructure and corrosion resistance of Ni-graphene oxide composite coating electrodeposited under supercritical carbon dioxide

摘要

This paper reports on microstructure and corrosion resistance of nickel-graphene oxide (Ni-GO) composite coatings electrodeposited in emulsified supercritical carbon dioxide (Sc-CO2) bath with pulse power. Effect of pulse current density on surface morphology, microstructure, average grain size, hardness and corrosion resistance of the resulting coatings was investigated in detail. The results reveal that incorporation of GO and assist of Sc-CO2 favors grain refinement and anticorrosion capability. The Ni-GO coating prepared under Sc-CO2 fluids shows more compact surface, smaller grain size, higher microhardness and stronger corrosion resistance than both the pure Ni coating produced in Sc-CO2 bath and Ni-GO composite coating electrodeposited by conventional method. In addition, the change of current density has great influence on the microhardness and corrosion resistance of the Ni-GO coating. It was found that texture coefficient at (111) preferred orientation, micro hardness and corrosion resistance of the Ni-GO coating were enhanced when applying current density from 2 to 6 A/dm(2).