Aluminium nitride powder is obtained by two processes, the most commonly used today being the carbothermic reduction of alumina followed by simultaneous nitrification of the powder formed.
This powder is then prepared for shaping by grinding and the addition of sintering additives. It can be formed using the following standard processes used in the production of ceramics: dry uniaxial pressing, cold isostatic pressing, tape casting, and also extrusion and moulding under pressure. It then undergoes a firing cycle under a nitrogen atmosphere between 1,650 and 1,900°C, and provides the final properties of the sintered material.
Aluminium nitride is mainly characterised by its excellent thermal conductivity which increases with the purity of the material. Typically, the aluminium nitride available on the market offers a thermal conductivity between 170 and 200 W/m.K. It has excellent electrical and mechanical properties, close to those of alumina. By contrast, its resistance to chemical corrosion is its weak point.
The natural market for this material is the electronics industry, in the broad sense for applications where electrical insulation and good thermal conductivity are required. For example, heat sinks for laser diodes, vacuum deposition chamber insulators for semiconductor equipment, substrates for microelectronic devices, etc.