DENSE AL2O3/ZRO2 PARTICULATE COMPOSITES BY FREE SINTERING OF COATED POWDERS

Composite powders, prepared by coating coarse ZrO2 particles with fine Al2O3 powder using a chemical precipitation technique, were compacted and sintered freely at a constant heating rate of 4-degrees-C/min to approximately 1600-degrees-C. Composites containing up to almost-equal-to 30 vol% inclusions were sintered to nearly full density under the same conditions used for the unreinforced matrix. Furthermore, the sintering kinetics were not influenced significantly by the inclusion volume fraction. The sinterability of the composites formed from the coated powders was significantly better than that for similar composites formed from mechanically mixed powders. The present data provide a further demonstration that the use of coated powders may have widespread applicability for the fabrication, by free sintering, of dense ceramic particulate composites.