Microstructure and Tribological Properties of Fe-based Composite Coatings Reinforced by Spherical WC Particles using Plasma Transferred Arc

In order to improve the wear resistance of 304 austenitic stainless steel, the Fe-based composite coatings reinforced by spherical WC particles using plasma transferred arc were prepared by adding mass fraction 30% and 60% WC to the Fe-based composite powder, and coated on 304 stainless steel. The microstructure, phase compositions, and microhardness of coatings were determined. At a load of 50 N and a sliding speed of 20 mm/s, dry sliding wear resistances of the composite coating were investigated. The results show that the presence of WC reinforced phase, Cr₇C₃hard phase and Cr-rich solution-strengthening austenite greatly increased the microhardness of the WC reinforced coatings. The microhardness of 30% WC and 60% WC coatings were HV_0.2665 and HV_0.2724, which increased by 21.1% and 31.9% as compared with the Fe-based coating, and were 3.7 and 4 times as high as that of 304 stainless steel respectively. The coefficient of friction and the wear rate were 0.59 and 2.639×10^–6 mm³·N^–1·m^–1 for 30% WC coating and 0.42 and 1.111×10^–6 mm³·N^–1·m^–1 for 60% WC coatings. And both 30% WC and 60% WC coatings presented excellent wear resistance. Adhesive and two-body abrasive wear were predominant for 30% WC coating, whereas three-body abrasion was the main wear mechanism for 60% WC coating.