Alternative Metallic Binders for High Performance Cermets

Ceramic-metal composites, or cermets, are extensively used in demanding tribological and corrosive environments, and invariably combine the best properties of both constituents. The most widely used system, as both bulk materials and coatings, is based on tungsten carbide with a cobalt binder (WC-Co). However, WC-Co suffers from several limitations, including high mass, poor resistance to aqueous corrosion and significant elevated temperature property degradation. Two new cermet systems are discussed in the current work, using either stainless steel or ductile nickel aluminide based binder alloys. These binders have been paired with either titanium carbide (TiC) or carbonitride (Ti(C,N)) hard ceramic phases, to minimize component mass. The cermets have been examined in terms of their fundamental mechanical properties, and resistance to aqueous corrosion and sliding wear. These new cermet systems exhibit comparable sliding wear resistance to WC-Co, while showing corrosion rates that are two to three orders of magnitude lower. The relative performance characteristics of the two new cermet systems will be examined in comparison with a variety of current alternate cermet systems.