Synthesis, Structural, and Mechanical Properties of Alumina-Yttria-Stabilized Zirconia Nanocomposites for Prospective Dental Ceramics

Yttria-tetragonal-stabilized zirconia (YSZ) and alumina are common ceramics used in dental aesthetics/prosthetics. Their combination leads to composites with improved mechanical strength and toughness. In this work, different amounts of alumina are added to YSZ by mechanosynthesis to study the influence on the microstructural, mechanical, and aging properties of the blended nanocomposites. Moreover, a comparison with the properties of nanocomposites prepared by sol-gel method is also performed. For both cases, approximate to 3 mol% of yttria in zirconia proves to be an adequate amount to stabilize the tetragonal and cubic phases of zirconia at environmental temperature, with only low amounts of the monoclinic phase present. Vickers microhardness (HV) and scratching tests show that the nanocomposites with 3 mol% of alumina exhibit better mechanical properties, considering the aimed potential application as dental ceramics, even when the materials are subjected to low-temperature degradation in artificial saliva. In fact, they can preserve their good toughness and HV, as well as the constituent crystalline phases under these accelerated degradation conditions.