ABSTRACT
The average phase compositions of the alumina ceramics were characterised using Electron probe microanalysis (EPMA). The surfaces of the Dynallox 96 (D-96) AG and Dynallox 100 (D-100) AG alumina ceramics were examined using scanning electron microscopy (SEM). The surfaces of the D-96 AG alumina test bars may have suffered greater damage during grinding since they were found to be rougher than the D-100 AG alumina test bars, given that both grades of alumina had been ground in exactly the same way. The microstructures of polished sections of both D-96 and D-100 alumina ceramics were not easily observed, lacking contrast, when examined using optical microscopy and SEM in the secondary electron detector mode. Thermal etching of D-96 AG alumina revealed a bi-modal grain size distribution. Thermal etching of D-100 AG alumina revealed a bi-modal grain size distribution. Post-grinding heat treatment was found to significantly affect the flexural strengths of both D-96 AG and D-100 AG standard alumina test bars.
