The sliding wear of TiC and Ti(C,N) cermets prepared with a stoichiometric Ni3Al binder

Abstract

TiC and Ti(C,N) based cermets offer several improved characteristics relative to conventional WC-based “hardmetals”, such as lower mass and improved oxidation resistance, which are combined with high toughness, hardness and wear resistance. In the present work the tribological behaviour of TiC and Ti(C,N) cermets has been evaluated under reciprocating sliding conditions. The cermets were produced using an in-situ, reaction sintering procedure to form the stoichiometric Ni3Al binder, with the binder contents varied from 20 to 40vol%. Wear tests were conducted using a ball-on-flat geometry, with a WC–6wt% Co sphere as the counter-face material, for loads from 20 to 60N. The wear response was characterised using a combination of optical profilometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and focused ion beam microscopy. Initially, two-body abrasive wear was observed to occur, which transitions to three-body abrasion through generation of debris from the cermet and counter-face materials. Ultimately, this wear debris is incorporated into a thin tribolayer within the wear track, which indicates a further transition to an adhesive wear mechanism. It was found that specific wear rates of the cermets increased with both applied load. The highest wear resistance was found for intermediate Ni3Al contents.