Hot Isostatic Pressing of Pre-Sintered Alumina

The effects of HIPing parameters such as temperature, pressure and time and powder characteristics on the densification of presintered alumina were studied to establish a theoretical densification model of HIPing. The characteristics of sintered bodies examined are the density and grain size. The obtained results were analyzed by the Ashby's densification model. The HIP sintering of alumina was governed by the grain boundary diffusion of aluminum ion. The densification rate increased markedly with increasing temperature and pressure of HIPing, and with decreasing grain size. The densification was accompanied by the grain growth. The densification rate predicted by the model agreed well with that by the experiments, if proper diffusion coefficients and grain growth rate were accomodated in the analysis.