Nitride Ceramics｜Aluminum Nitride Ceramics (AlN)

Aluminum nitride ceramics are ceramics with aluminum nitride (AIN) as the main crystal phase. AIN crystal is a covalent bond compound with [AIN4] tetrahedron as the structural unit, has a wurtzite structure, and belongs to the hexagonal crystal system. Chemical composition AI 65.81%, N 34.19%, specific gravity 3.261g/cm3, white or off-white, single crystal is colorless and transparent, the sublimation decomposition temperature under normal pressure is 2450℃. It is a high temperature heat resistant material. Thermal expansion coefficient (4.0-6.0) X10-6/℃. The thermal conductivity of polycrystalline AIN is 260W/(m.k), which is 5-8 times higher than that of alumina, so it has good thermal shock resistance and can withstand extreme heat of 2200℃. In addition, aluminum nitride has the property of not being attacked by molten aluminum and other molten metals and gallium arsenide, and especially has excellent corrosion resistance to molten aluminum.

Aluminum nitride ceramics have excellent thermal conductivity and thermal shock resistance, as well as good insulation. Due to liquid phase sintering and no second phase at grain boundaries, the crystal structure is very dense and has good resistance to plasma corrosion. It is widely used as a substrate and spare parts for semiconductor manufacturing equipment.

The main application of aluminum nitride ceramics
1. Aluminum nitride powder has high purity, small particle size and high activity. It is the main raw material for manufacturing high thermal conductivity aluminum nitride ceramic substrates.
2. Aluminum nitride ceramic substrate, high thermal conductivity, low expansion coefficient, high strength, high temperature resistance, chemical corrosion resistance, high resistivity, low dielectric loss, is an ideal large-scale integrated circuit heat dissipation substrate and packaging material.
3. Aluminum nitride has high hardness, surpassing traditional alumina, and is a new type of wear-resistant ceramic material, but due to its high cost, it can only be used for parts with severe wear.
4. Using AIN ceramics with heat resistance, melt corrosion resistance and thermal shock resistance, it can be produced as GaAs crystal crucibles, Al evaporating dishes, magnetic fluid power generation devices and high temperature turbine corrosion-resistant parts. And with its optical properties, it can be used as infrared windows. Aluminum nitride films can be made into high frequency piezoelectric components, VLSI substrates, etc.
5. Aluminum nitride is heat-resistant and resistant to erosion of molten metal, stable to acid, but easily eroded in alkaline solution. The nascent surface of AIN will react to form a very thin oxide film when exposed to humid air. Taking advantage of this characteristic, it can be used as crucible and casting mold material for smelting aluminum, copper, silver, lead and other metals. AIN ceramics have good metallization properties and can replace toxic beryllium oxide ceramics and are widely used in the electronics industry.