Use of FIB/SEM to assess the tribo-corrosion of WC/Co hardmetals in model single point abrasion experiments

This paper describes the results of experiments where single point model abrasion experiments were carried out under a range of conditions of applied load and different media. FIB/SEM revealed that in air, damage occurred by binder extrusion in conjunction with fragmentation and fracture of the tungsten carbide grains, with re-embedment of fragments of carbide in the binder phase to form surface layers of mechanically mixed material. In HCl the binder was preferentially removed leaving the WC grains unsupported leading to further fracture and breakdown of the surface of the hardmetal. FIB revealed subsurface cobalt dissolution. A cobalt–nickel binder material proved the most versatile in resisting surface degradation in both ambient air and in HCl.