Friction Behavior of WC-12Co, WC-10Co4Cr and Cr3C2-25NiCr Coatings Prepared by HVOF in Different Media

In order to study the friction behavior of hard surface coatings in different media, the coatings were prepared by high-velocity oxygen-fuel (HVOF) with WC-12Co, WC-10Co4Cr and Cr3C2-25NiCr materials as raw materials. The hardness, morphologies of the wear track of the coatings were analyzed by micro-hardness tester, wear tester and SEM. The results show that the porosity of the coating is closely related to the content of the binder phase. When the binder phase (Co) content is 12wt%, the porosity of the coating is 1.11%. When the binder phase (CoCr) content is 14wt%, the porosity of the coating is 0.98%. When the binder phase (NiCr) content is 25wt%, the porosity is reduced to 0.92%. In air, WC-10Co4Cr has the highest hardness and the lowest friction coefficient, while Cr3C2-25NiCr has the lowest hardness and the highest friction coefficient. In the environment of 1 mol/L HCl, the best corrosion resistance of NiCr binder makes the friction coefficient of Cr3C2-25NiCr coating stable, and the poor corrosion resistance of pure Co and CoCr makes the friction coefficient of WC-10Co4Cr and WC-12Co coatings with high and low fluctuations. In the friction process in 1 mol/L NaOH environment, the corrosion of hard phase can reduce the hardness and increase the friction coefficient.