Tribo-oxidation and tribological behaviour of ZrB2-20%volSiC composites coupled with WC and Al2O3 at high temperatures

Abstract

ZrB2-20%volSiC composites were hot pressed with ZrB2 and SiC powders and the effect of temperature and friction couples (WC or Al2O3) on the tribological properties of these composites was investigated. The results show that the coefficient of friction (CoF) of ZrB2–SiC composites coupled with WC or Al2O3 was almost constant with respect to temperature (0.5–0.6). Meanwhile, their wear rates (WRs) were of the order of 10−4 mm3 N−1 m−1. Either discontinuous (with WC) or continuous (with Al2O3) tribo-layers were found to have been formed on the worn surfaces of the composites and these tribo-layers did not exhibit any lubricious or anti-wear effects. At temperatures of 25–400 °C, the wear mechanism of the composites coupled with WC and Al2O3 included abrasion, tribo-oxidation, and adhesion. At higher temperatures (600–800 °C), the wear mechanism of both tribo-pairs included tribo-oxidation and adhesion.