Novel technique for synthesis and consolidation of aluminium nitride nanopowders

In this paper, the use of a microwave plasma method for the synthesis of aluminium nitride nanopowders is described. The powders were consolidated to near theoretical densities using the unique rapid consolidation technique, plasma pressure consolidation ((PC)-C-2), developed by MMI. Rapid consolidation of nanopowders is an ideal requirement for better mechanical and thermal properties in the consolidated part, as it retains the fine microstructure preventing anomalous grain growth. Microwave plasma synthesis resulted in aluminium nitride nanopowders (85-200 nm), which were consolidated to near theoretical density using (PC)-C-2 in <5 min without sintering additives. The effect of yttria (3 wt-%) as a sintering additive on the thermal conductivity (TC) of aluminium nitride was also evaluated and compared with TC values obtained from additive free AIN consolidated samples.