Simulation of abrasion to WC/Co hardmetals using a micro-tribology test system

Abstract Abrasion is an important mode of wear that causes considerable damage in application in the materials handling and mineral extraction sectors. There has been considerable recent progress in defining the wear mechanisms that occur in abrasion and their relationship to the microstructure of materials such as WC/Co. Much of this deeper understanding has been developed using scratch testing as a model of single point damage to a sample. However, in abrasion the damage is caused by multiple scratch events which are not reflected in the single point experiments. This paper describes how a computer controlled micro-tribometer system was modified to carry out simulated abrasion experiments where areas on polished samples of WC/Co were subjected to sets of randomly distributed scratches (both spatially and in terms of load). The time progression of damage was identified by carrying out simulations with different numbers of scratches up to 10,000 in a mm wide area. The microstructural mechanisms of damage were characterised by high resolution SEM combined with selected 3D FIB-SEM analysis. The examination was combined with knowledge of the scratching history (including friction results) that had been recorded for any specific position on the sample. In line with previous observations, it was found that the mechanisms of damage that occurred were removal of the cobalt from the binder phase region of the sample, cracking of the WC grains and re-embedment of WC fragments into remaining binder phase.