Aluminum nitride hardness is one of the most important and popular technical ceramics materials, which possesses excellent corrosion resistance and high thermal conductivity. It is widely used in electrical power equipment, microelectronics and machinery applications. It is also used as a substrate material in semiconductors, and has a wide range of insulating properties.
Aluminum nitride can be prepared by the reduction of alumina and carbon or by direct nitriding. It has a hexagonal crystal structure and is a covalently bonded material. AlN has a high melting point, thermal conductivity and electrical insulation properties.
Aside from its excellent corrosion resistance, high thermal conductivity and electrical insulation properties, it is also non-toxic and has a high dielectric constant. This makes aluminum nitride the ideal choice for many electronic instruments, which need to meet strict temperature and humidity requirements.
Compared with other group 13 nitrides and phosphides, the hardness of aluminum nitride exhibits a gradual decrease from room temperature (RT) to 700degC, followed by a plateau in the upper part of the range. This phenomenon is similar to that seen in semiconductors with a hexagonal crystal structure, such as GaN and SiC.
Hardness measurements were carried out on the (0001) surfaces of the crystals using the conventional Vickers micro-indentation method with a pyramidal diamond indenter. The applied indentation load was 0.5 – 5 N and the dwell time was 30 s.