Cermet is a composite structural material composed of ceramic hard phase and metal / alloy bonding phase. The English word is cermets, which is composed of cer in ceramic and met in metal. It is mainly divided into TiC-based and Ti (C, N) -based alloys. Ti (C, N) -based cermets are sometimes referred to as cemented carbides or cemented carbides. Their hardness and heat resistance are close to ceramics, and their bending strength and fracture toughness are higher than ceramics.
Development path
The study of cermet materials originally originated in 1929, mainly based on the study of TiC groups, and the related literature reports are mainly based on the study of bonding phase. The traditionally called WC-Co cemented carbide is made of a combination of ceramic hard phase WC and metallic Co. It can also be called a cermet. A large part of the research on new cermets is to replace WC-Co Carbide, which can save W and Co of strategic significance, which has very important practical significance for countries with scarce resources. At the end of the 1970s, Ti (C, N) -based cermets appeared in the European metal processing industry; they appeared in Japan in the early 1980s; China developed a variety of Ti (C, N) -based during the "Eighth Five-Year Plan" period Cermet cutter.
Application
Ti (C, N) -based cermet materials have the advantages of low density, greenhouse hardness and high-temperature hardness better than WC-based cemented carbide, good chemical stability and corrosion resistance, good wear resistance and thermal conductivity, can replace WC Carbide-based and TiC-based cermets are widely used in the processing of ordinary carbon steel, alloy steel and cast iron, and the precision milling of steel parts. Its scope of application fills the gap between high-speed finishing and semi-finishing between WC-based cemented carbide and ceramic tools. It is not only suitable for high-speed finishing, but also suitable for semi-finishing and intermittent cutting of steel, etc. , Good surface quality and long tool life. Ti (C, N) -based cermets can also be used to make miniature indexable inserts for precision boring, fine hole machining and turning instead of grinding. The low density, good friction performance, stable high temperature strength and excellent acid and alkali corrosion resistance of Ti (C, N) -based cermets make it suitable for high-temperature parts of engines, sealing rings in the petroleum and chemical fiber industries And valves and various measuring tools.
Prospects
The main reason for limiting the large-scale application of Ti (C, N) -based cermet composite materials in high-end cutting tools and hot extrusion dies is the insufficient strength and toughness of the material. Increase the development of ultra-fine-grain cermet composite materials with uniform structure, promote the development of ultra-fine grain hard tool materials and hot extrusion die materials in China, and promote the update of high-end hard tools and hot extrusion die materials Generation and technological progress have important significance.