Low-temperature sintering of AlN ceramics with shock wave treated powder

AlN powder was shock wave treated under a pressure of 9.8 GPa. X-ray line broadening effect was observed in the shocked powder, which is attributed to the stored strain in the lattice caused by the shock wave treatment. The strain is appreciable and has a value up to about 3 X 10(-3) for the (100) plane, which is released during sintering process and provides a driving force for densification. Sintered at 1610 degrees C for 4 h, the shocked compact doped with additives has a density of about 98% of the theoretical density, while only 80% for the unshocked compact. This suggests that the shock waves have an ''active'' impact on the AlN powder and make it possible for low-temperature sintering.