Flaw Size Distribution in High‐Quality Alumina

A difference in fracture strength was noted among commercial alumina ceramics. The origin of this difference was examined using optical microscopy in the transmission mode. Large defects measuring several tens of micrometers or more were clearly observed, and a direct correlation was found between the size of the large defects and the strength of the ceramics. The results indicated that a low concentration of large defects controlled the strength distribution of the ceramics studied.