Influence of secondary phases on the tribological response of electro-discharge machined zirconia-based composites against WC-Co cemented carbide

Three ceramic composite grades, consisting of a ZrO2 matrix and 40 vol.% WC, TiC0.5N0.5 or TiN phase, were completely self-developed by hot pressing powder mixtures of yttria-stabilised zirconia (Y-TZP) and distinctive WC, TiC0.5N0.5 or TiN powder sources. The friction and wear characteristics of the zirconia-based composites against WC-Co cemented carbide were investigated by performing dry reciprocating sliding experiments on a pin-on-plate tribometer under various normal contact forces. The generated wear was quantified using surface scanning topography. Post-mortem obtained wear volumes were correlated to real-time recorded wear depth. The ZrO2-40 vol.% WC grade displayed more favorable tribological properties compared to the other grades with equal secondary phase content. The worn surfaces and the wear debris were analysed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), revealing several wear mechanisms such as polishing, abrasion and wear debris layer formation, mainly depending on the imposed contact load and the material composition.