Wear Performance of the Plasma Sprayed Fine WC-Co Composite Powders Coatings

Abstract

WC/Co; Composite coating; Plasma spraying; Friction and wear Abstract: WC- Co composite powders were synthesized by direct mechanical grinding in a rotary-vibration mill under 8h, and then analyzed by SEM and XRD. WC and WC/Co composite coatings were prepared by supersonic plasma spraying fine WC-Co composite powders. The wear and friction properties of both coatings were evaluated. The results showed that the wear resistance of the WC/Co composite coating was superior to that of the WC coating. The improvement in wear resistance of the WC/Co composite coating was attributed to its higher fracture toughness and adhesion strength as well as better thermal diffusivity. As for the WC/Co composite coating, the mechanism was mainly adhesion with micro-abrasion and fatigued-induced brittle fracture within splats, and the delamination along splat boundaries only occurred at high load. However, the failure of the WC coating was predominantly detachment of transferred film and brittle fracture within the splats and delamination along splat boundaries, which were enhanced with the increasing load.