Combustion Synthesis of Fine and High-Purity AlN Powder and Its Reaction Control
Toshitaka SAKURAI, Yoshinari MIYAMOTO and Osamu YAMADA
Abstract:The aluminum nitride powder synthesized by combustion synthesis (SHS) process usually includes course particles because of its high reaction temperature. These powders are not suitable for sintering, and strong pulverization is necessary. The reduction of the primary particle size of AlN powder synthesized by SHS was studied by adding reaction controlling agents. The results showed that some additives cause a remarkable decrease in its reaction temperature and increase in specific surface area of the product powders. Pulverization and sintering of these products are then carried out and the characteristics of the sintered body were evaluated. The average particle sizes, after 30 minutes pulverization by planetary mill, were 1.3 ƒÊm for the AlN synthesized with 3 mass% NH4F as a reaction controlling agent, and 1.7 ƒÊm without NH4F. Sintering of these powders was carried out by using spark plasma sintering(SPS) at 1823 K and obtained relative densities were 98.7 % and 91.9 %, respectively. Key Words:Aluminum-nitride, AlN, Combustion-synthesis, SHS, Reaction-control, Ammonium-fluoride, Aluminum-fluoride, Specific-surface-area,Pparticle-size, Sintering density