Effect of pulse duty cycle on microstructure and properties of graphene composite coating under supercritical carbon dioxide

Abstract

The supercritical nickel-graphene composite coating was prepared by supercritical carbon dioxide fluid(SCF-CO2) assisted pulsed composite electrodeposition technique with graphene oxide (GO) as the second phase additive. The effect of pulse duty cycle on the microstructure and mecha-nical properties of the coatings was investigated. The results show that the microstructure of composite coating can be refined significantly by the combination of supercritical carbon dioxide fluid and graphene oxide. The change of the (111) and (200) peaks in the XRD patterns of the composite coating shows that change occurs in preferred orientation during the crystallization process. The change of duty cycle has great influence on the mechanical properties of the coatings. The micro-hardness of the supercritical nickel-graphene composite coating is as high as 756.8HV0.2 and the cross-sectional area of wear scar is 4385μm2 at 50% duty cycle. Compared with the nickel-graphene comp-osite coating prepared under conventional conditions, the microhardness and wear resistance of super-critical nickel-graphene composite coating are increased by 1.6 and 11 times.

Keywords

• SCF-CO₂
• graphene
• duty cycle
• mechanical property
• microstructure