Tribological analysis of WC cermet coatings with friction test under tensile stress condition

摘要

This paper describes tribological properties of WC cermet coating layers which are thermally sprayed with HVOF. On the assumption of the severe sliding condition in which large compress and tensile stress are applied to a surface layer simultaneously, relatively hard material is chosen as counter parts and additional tensile stress is applied. WC/12%Co, WC/10%Co/4%Cr and WC/20%CrC/7%Ni are employed as coating material. From the experimental results, it is found that the WC cermet spray coatings by the HVOF are inferior to sintered WC/Co with regard to fracture toughness near the surface and pseudo plastic deformation which are main wear behavior in severe sliding condition. It is also found that a heat treatment has certain effect to eliminate the wear caused by the surface fracture, while, for the pseudo plastic deformation, it does not exhibit much effect.