Superhard Materials Research Status & Application

Research Status

As a kind of important engineering material, superhard material refers to materials whose Mohs hardness is close to 10, mainly used in composite materials, inorganic non-metallic materials, and hard alloy processing. Besides that, some superhard materials have special properties in optics, electricity, and thermology. Major forms of superhard materials include diamond (natural diamond, synthetic diamond) and CBN (Cubic Boron Nitride). 

Superhard materials are composed generally of superhard grains and bonding agents. China's superhard materials have a history of 50 years. For nearly half a century, China's superhard materials products have made progress both in terms of products and technology.

Most natural diamonds are formed at high temperature and pressure. Synthetic diamonds are diamonds manufactured in a laboratory, as opposed to diamonds mined from the Earth. The majority of commercially available synthetic diamonds are yellow and are produced by so-called High Pressure High Temperature (HPHT) processes. The yellow color is caused by nitrogen impurities. Other colors may also be reproduced such as blue, green or pink, which are a result of the addition of boron or from irradiation after synthesis. Cubic boron nitride is widely used as an abrasive. Materials with cubic boron nitride crystals are often used in the tool bits of cutting tools. 

Application

Diamond has a superior performance thanks to its high hardness. It can be used to process all kind of difficult-to-process materials, and is suitable for ultra-fine cutting on non-ferrous metals. Diamond and CBN monocrystalline powder is widely used in production of abrasives, abrasives products, polishing pastes, abrasive cloth, and sand paper. What's more, diamond is also used for making diamond wire drawing dies, diamond dressing tools, and diamond drill bits.

CBN has high hardness and high thermal stability, so it is suitable for cutting all kinds of steel alloy, high-speed steel, and cast steel. However, the working life of CBN is shorter than diamond.