Titanium carbonitride-based cermets: processes and properties

Cermet is a structural material in which approximately equiaxed fine grains of ceramic hard phase embed in a matrix of metal or alloy binder. Titanium carbonitride-based cermets were first invented in the 1930s, but the boom of the cutting grades really started in the early 1970s when titanium carbide-based cermets were established. However, because of their superior properties, the Ti(C,N)-based cermets are now in a process of replacing the TiC-based cermets for cutting tool applications. In traditional titanium carbonitride-based cermets, polybdenum is regarded as the indispensable ingredient for wettability and sinterability, at the expense of grinding machinability. With the recent invention of the pre-sintering solid-solution treatment of the ceramic hard phase, the materials development of titanium carbonitride cermets has come to a new stage where molybdenum is no longer indispensable. For cermets of very high nitrogen content, however, the combination of solid-solution treatment and a moderate molybdenum addition is predicted to be the way out.