Analysis of White Spots in High-Density Alumina.
BATTELLE COLUMBUS LABS OHIO
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The development of white spots in translucent alumina bodies fabricated from reactive powders was investigated. Emphasis was placed on the determination of the relationships of powder preparation procedures and particulate character to the introduction of these microstructural inhomogeneities in high-density sintered alumina. The white spots were shown to consist of porous microstructure inhomogeneities and to be attributable to nonuniformities in the starting powder. The introduction of this condition during powder processing was traced, primarily by compaction analysis and electron microscopy, and found to be caused by grinding-aid additions. Elimination of the nonuniform distribution of milling aid resulted in elimination of white spots from the alumina microstructures, and was accompanied by increased strength in compacts fabricated from the dry-milled alumina powder. Author
- Ceramics, Refractories and Glass