Nanocrystalline Aluminum Nitride: II, Sintering and Properties

Abstract

Nanocrystalline aluminum nitride powders obtained from gas condensation and in situ nitridation in a forced‐flow reactor have been sintered successfully without pressure or additives. The resulting densified pellets showed good thermal conductivity and low oxygen content. A comparison of the improvement in densification with micrometer‐size and nanocrystalline yttria additives was undertaken and it was found that the nanocrystalline yttria decreased the sintering temperature significantly. Besides spherical nanoparticles, needle‐shaped nanocrystalline aluminum nitride particles that resulted in highly textured compacts when hot pressed could also be produced.