Formation of alpha-Al2O3 from Al(OH)(3) in the presence of seed particles and its sinterability - The role as a seed of ball abrasion powder in vibration milling

Effect of wet grinding of commercial aluminum hydroxide on the transformation to alpha-alumina during heating was investigated using vibration ball mill. The grinding with high purity alumina balls reduced the transformation temperature to alpha-alumina by 300 degrees C. Such significant reduction in the transformation temperature was not observed in the samples obtained by the grindings with zirconia and low purity alumina balls. The formation of alpha-alumina from ground aluminum hydroxide at such a low temperature was possibly attributed to a seed-effect of fine alpha-alumina powder worn from the balls and its uniform mixing with the mother powder during grinding. The alpha-alumina powder made from ground aluminum hydroxide consisted of very fine particles, which enabled us to sinter at a relatively low temperature. The sintered bodies had fine-grained structure without abnormal grain growth.