2013 年 56 巻 p. 31-37
Two of the most important problems in ceramics are the large variation of properties and the shape deformation of products in processing. Packing structures of particles were examined to clarify their origins in various intermediate products appearing in production process of ceramics. As a model system, processing of alumina ceramics though compaction forming was selected, and the structures of granules, green compacts and ceramics were examined with unique optical methods developed by the present author. A variety of interesting structure was discovered, directly showing their clear relationship to various problems caused by them. A very interesting defect size distribution was found in an alumina ceramic for the first time. It successfully explained the strength variation of the ceramics quantitatively for the first time in the history of fracture mechanics. The importance of particle orientation on deformation during sintering was emphasized.