High sphericity AlN powder carbothermal reduced from spray granulated Al2O3/C precursor

In this work, a simple, safe, and low-cost two-step route for preparing spherical AlN powders was developed. Specifically, pure AlN spherical powder can be obtained by using water as the solvent, ammonium polyacrylate as the dispersant, carbon powder and alumina powder as the raw materials, spraying and granulating into a spherical precursor, and then sintering at high temperature under a nitrogen atmosphere. The results demonstrate that the average size and the associated distribution of the precursor can be adjusted by regulating the solid or dispersant content of the slurry, which is beneficial for governing the size of the AlN powder. The average particle size of the sintered spherical AlN powders is approximately 33.5 μm, presenting high sphericity (greater than 0.9) and excellent flowability. This approach developed for preparing spherical AlN powder is of great significance for promoting the widespread application of AlN powder in the field of high-performance fillers.