Sintering and grain growth of ultrapure alumina

摘要: The kinetics of densification and grain growth ultrapure alumina (> 99.999%) were measured for clean sintering conditions in a pure-sapphire tube, compared with during normal an crucible 99.8% purity. For the condition, microstructure sintered remained homogeneous only was observed up to 1900°C 5 H. However, under both abnormal depending on temperature time. Thus, could be effectively suppressed without introducing aids (such as MgO) by using powder preventing introduction any impurities throughout process. This result strongly suggests that commercially pure (⩽ 99.99%) is not intrinsic property but extrinsic controlled minor constituents can present original or introduced processing subsequent sintering.