Cermet

A cermet is a composite material composed of ceramic and metallic constituents designed to combine the advantageous properties of both classes. The ceramic phase provides high hardness and wear resistance, while the metal phase contributes toughness, some ductility, and improve fracture resistance.

Typically, cermets employ a ceramic reinforcing phase such as tungsten carbide, titanium carbide, silicon carbide, or various nitrides and oxides, dispersed in a metallic binder such as cobalt, nickel, iron, or their alloys. The microstructure often consists of ceramic grains within a metallic matrix, or a distribution of ceramic particles embedded in a metal binder. Processing is usually achieved by powder metallurgy: blending ceramic and metal powders, pressing, and sintering at high temperature, with possible liquid-phase sintering to enhance bonding and densification.

Cermets exhibit high hardness and excellent wear resistance, along with better thermal stability than many metals. They retain hardness at elevated temperatures more effectively than most metals, making them suitable for high-speed cutting and other demanding surfaces. While they are tougher than monolithic ceramics, they remain relatively brittle compared with conventional metals, so design and impact loading must be considered.

Applications are concentrated in cutting tools, wear parts, dies, and punches where high wear resistance and hot hardness are advantageous. The most common commercial cermets are tungsten carbide particles in a cobalt or nickel binder (often referred to as cemented carbides), with alternative formulations using different carbides and binders to tailor properties for specific applications. Other cermets use various ceramic phases with nickel, iron, or copper binders to achieve different performance goals.