Combustion synthesis of aluminum nitride powder using additives

Aluminum nitride powder was synthesized by a combustion synthesis method using various additives. Each additive was mixed with Al powder, and the powder mixture was then pressed into a compact. The combustion reaction was ignited by heating the compact under N2 atmosphere of 0.4 MPa. Additives containing halogens were found to have a catalytic effect on the combustion reaction. High product yields were obtained when using additives of NH₄X, CO(NH₂)₂, CH₃(CH₂)₁₆COOH, and CO₂H(CH₂)₂CO₂H. In all these cases, eggshell-like skins were observed to form on the Al particles at the early stage of combustion. The catalytic effect, formation of the eggshell-like skins, and their effects on the combustion process were investigated and discussed.