The sliding wear response of high-performance cermets

Abstract

The degradation of materials through wear is of significant concern in a wide variety of industries. As a consequence, there is a continuing drive to develop improved materials for many of these applications, and to thoroughly assess their wear response. One class of materials that is widely employed in scenarios requiring both wear and corrosion resistance is composites combining ceramics and metals, often referred to as “cermets.” Among the commonly applied cermet systems, materials based on WC with a Co-based metallic binder are widely employed. More recently, lightweight cermets based on TiC and Ti(C, N) are finding application in many industries. The present study summarizes recent investigations assessing the sliding wear response of TiC and Ti(C, N) cermets, utilizing novel metallic binder phases, including various stainless steels and ductile nickel aluminide intermetallics. It is shown that these materials present a complex response to sliding wear. Initially, two-body abrasive wear occurs, which rapidly transitions to three-body abrasive wear. The third-body material is comprised of constituents from the two contacting materials, generated through mechanisms such as binder extrusion and ceramic grain fracture and pull-out. Ultimately, the third-body material is significantly refined in size, and is deposited into the wear track via an adhesion mechanism, as a thin tribolayer. It is demonstrated that specific wear rates comparable to current commercial WC-based cermets can be achieved with these new lightweight materials.