The invention provides a method for preparing a spherical aluminum
nitride powder. The method comprises the following steps of: 1, mixing aluminum
powder with aluminum
nitride powder and
ammonium chloride powder, putting the mixture into a
mortar for
grinding, wherein the aluminum powder is spherical aluminum powder having the particle size range from 0.5 micron to 3 microns; and the aluminum
nitride powder is prepared from an aluminum source which is spherical aluminum powder having the same particle size with the
raw material aluminum powder through in-situ nitrogenation; 2, putting the evenly ground powder in a porous
graphite crucible with a
graphitic carbon felt exterior heat preservation layer and an interior protective layer and reacting in a reaction device; 3, electrifying
graphite paper, and igniting the powder from bottom to cause a
combustion reaction; 4, after natural cooling, releasing
nitrogen in the
reaction chamber, and opening the reaction device, and obtaining an off-
white powder in the porous
graphite crucible, namely the spherical aluminum nitride powder; and 5, controlling the particle size of the spherical aluminum nitride powder through the particle size of the spherical aluminum powder. The method provided by the invention has the characteristics of low
energy consumption, simple process and low cost; and the prepared spherical aluminum nitride powder is good in homogeneity and controllable in particle size.