Effects of heat treatment on microstructure and properties of Ni-W-GO composite coatings

Graphene oxide (GO) has been extensively studied due to its unique structure and characteristics. In the study, with GO nano-sheets used as the hard phase, Ni-W-GO composite coatings were obtained on a 45#steel substrate by direct current electrodeposition. The coatings were subject to vacuum heat treatment at different temperatures.Their microstructure, phase, mechanical performance, and friction and wear properties were analyzed by SEM, XRD, microhardness tester and wear testerbefore and after heat treatment. Their wear mechanism was also investigated. The results show that the grain size of the coatings increases gradually, combined with micro cracks emerging, and mesophase particles separating out in the processof heat treatment. With the increase of heat treatment temperature, the microhardness and wear properties of the coatings first increase, and then decrease. When the temperature is 350 ℃, its hardness is the highest reaching 840 Hv.