Wear Behavior of Electro-brush Plating Nano-WC/PTFE-Ni Composite Coatings

Nickel-base composite coatings containing nanometer WC and PTFE were prepared by electro-brush plating on Q235 steel substrate. The morphology and microstructure of the coatings were observed on a S-2700 scanning electron microscopy. HX-1 microhardness tester was used to determine the hardness of the coatings. The adhesion strength was measured using a WS-2005 scratch tester and wear resistance tests were performed using a HT-500 pinon-disc tribometer. It was found that with addition of WC and PTFE, the surface morphology of the composite coatings became fiat and compact. The micro-hardness of the composite coatings increased with increase of the content of WC in the bath but decreased with increase of the content of PTFE in the bath. The composite coatings with two kinds of nanometer particles showed good tribological behavior. When the contents of WC and PTFE in the bath were 3 g/L and 7.5 ml/L respectively, the microhardness of the composite coating could reach to HV700, which was 30% higher than nickel coating, and the wear resistance of the composite coating was 7 times higher than pure nickel coating.