CERAMIC MATERIALS WITH ENHANCED RESISTANCE TO FRACTURE AND PREDICTABLE STRENGTH AND METHOD OF MAKING THE SAME

摘要

TITLE CERAMIC MATERIALS WITH ENHANCED RESISTANCE TO FRACTURE AND PREDICTABLE STRENGTH AND METHOD OF MAKING THE SAME INVENTORS Patrick Stephen NICHOLSON and Tomasz TROCZYNSKI Ceramic materials may be impregnated with a material, whose grain structure (morphology) is platey and ground so that its macro size is consistent with that of the adjacent ceramic matrix and sintered to form a composite ceramic. In the composite ceramic, the macro platey impurity acts as a barrier or site for deflecting migrating fissures which are forced on the composite ceramic as a result of stress. Disclosed, particularly is a ceramic composite of partially stabilized zirconia (PSZ) employing a .beta.-Alumina impurity; (X-.beta.-Al2O3), where X is a cation, preferably Na+. The abbreviated chemical composition of the composite ceramic is PSZ-.beta.-Al2O3. The .beta.-Al2O3 component thereof has a preferred grain size of between 50 and 120 microns, although up to 500 microns will do when dispersed through the zirconia in a volume ratio of approximately 20% for the .beta.-Al2O3 component. This tends to increase by an order of magnitude, the nonelastic work necessary in order to destroy the composite ceramic while at the same time giving a high Weibull Modulus so that the probability of fracture, .alpha., for composite ceramic sample produced according to the invention has a value of about 0.1%. That the Weibull Modulus can exceed 40.