At present, more methods for preparing aluminum nitride powder are direct nitriding of aluminum powder, carbothermal reduction of alumina, sol method, self-burning method, plasma composition method, polymer decomposition method containing ALN bond, chemical vapor deposition method, water-induced solid phase reaction method, sol-gel method, etc. The following small series introduces the commonly used composition method of aluminum nitride powder.

1) Aluminum powder direct nitriding method

AlN+N2→2AlN The aluminum powder is heated to 600℃ in a reaction furnace with the reaction of nitrogen and ammonia. This is a simple and direct method, can form a lot of high purity ALN powder, no side effects, now has large-scale production.

However, this method is generally difficult to obtain fine particles and uniform particle size aluminum nitride powder, which generally requires post-treatment. In addition, the ALN layer formed by the nitriding of the surface of the AL particles will prevent the dispersion of nitrogen to the center of the particles, so the conversion rate of this method is also a major question.

2) carbothermal reduction of alumina

Al203+3C+N2→2AlN+3CO This method is now widely used in industrial production, and the comparison of its research is deepened.

In the preparation of aluminum nitride powder, calcium oxide, calcium fluoride, yttrium oxide are often used as catalysts, among which calcium fluoride is more useful to reduce the activation energy and improve the reaction rate. The prepared aluminum nitride powder has high purity, good forming and sintering properties, but high composition temperature and long reaction time, and large powder size.