Production of alumina ceramics reinforced with beta '''-alumina

摘要

A process for producing strong alumina ceramics in which needle-shaped beta '''-alumina grains are homogeneously distributed in an alpha -alumina matrix to provide an increase in bending strength, as compared to the alumina ceramics without beta '''-alumina, when fired under similar conditions. The process comprises mixing alpha -alumina powder and salts of sodium and magnesium, in a Na:Mg mol ratio of 1:2; wet-mixing and calcining the mixture to form a mixture of (100-5X) mols of Al2O3+X(Na2O+4MgO), wherein X is the number of mols and is not more than 3; forming a dense green body of the calcined mixture and sintering the green body at a temperature and for a time sufficient to form in-situ particles of beta '''-alumina distributed in the alpha -alumina.