Tribological performances of ZrC-Ni and TiC-Ni cermet reinforced PTA hardfacings at elevated temperatures

The aim of this study was to characterise TiC-Ni and ZrC-Ni cermet reinforced NiCrBSi hardfacings in a 40:60 vol.% ratio respectively and to investigate their respective wear behaviour at temperatures up to 700 °C. Coatings were produced using plasma transferred arc welding; optimised methods and parameters were meant to ensure a uniform distribution of the cermet across the metal matrix composite. High-temperature testing included macro hot-hardness, cyclic impact abrasion, and cyclic abrasion, all featuring temperatures between room temperature and 700 °C. During cyclic abrasion, both TiC-Ni and ZrC-Ni reinforced hardfacing show decreasing wear rate with increasing temperatures. During impact abrasion testing, it was shown that TiC-Ni and ZrC-Ni reinforced hardfacings possess superior wear properties in comparison to conventional WC reinforced ones. The role of TiO2 oxide, and in the case of ZrC-Ni, the role of a complex mixed carbide phase, M23C6, played an important role in stabilising the kinetics of oxidative wear at temperatures beyond 500 °C.