Abstract
The sintering behaviour of magnesium aluminate spinel on both sides of the stoichiometry has been investigated. It is found that the composition close to the stoichiometric composition, but slightly enriched in magnesia can be sintered to translucency in a free flowing hydrogen environment. The grain size decreases with magnesia content; the addition of yttria, however, results in a highly bimodal grain structure. Prolonged exposure of the spinel in a high temperature sodium vapour environment forms Na2O · 5Al2O3 and some traces of Na2O · 11Al2O3 predominantely at the grain boundaries and near the surface of the specimen. Some possible sintering mechanism and factors affecting the in-line transmission are discussed.
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Hing, P. Fabrication of translucent magnesium aluminate spinel and its compatibility in sodium vapour. J Mater Sci 11, 1919–1926 (1976). https://doi.org/10.1007/BF00708270
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DOI: https://doi.org/10.1007/BF00708270