Processing and Application of Ceramics (Jun 2008)
Influence of forming method and sintering process on densification and final microstructure of submicrometre alumina ceramics
Abstract
Conditions of green body preparation and consequently the conditions of sintering are prerequisite for the preparation of dense samples of Al2O3 with superior optical and mechanical properties. The goal of this work was to determine the optimum forming conditions for preparation of green body, and to find out the optimal sintering regime facilitating the preparation of ultra-fine grained high purity alumina with maximal density, fine microstructure and small pore size. Axial pressing followed by CIP was found to yield green body with the highest density and narrowest pore size distribution. In the two-stage sintering regime the temperature T1 has to be higher or equal to 1300°C to obtain closed porosity unstable against shrinkage. The temperature T2≥1130°C was found to be too high for suppression of grain growth in the final stage of sintering and sintering trajectory was identical with that from standard sintering regime.
