Evaluation of 1.5 mol% yttria – 1.5 mol% gadolinia stabilized tetragonal zirconia polycrystals derived from solid state synthesis and laser vaporation

Abstract

Variation of stabilizer composition and amount offers the opportunity to tailor the mechanical properties of tetragonal zirconia polycrystals. In this study, zirconia stabilized with 1.5 mol% yttria and 1.5 mol% gadolinia was prepared by co-milling zirconia with yttria and gadolinia stabilizer oxides. A laser vaporized powder was derived from this starting powder. The two powders were subsequently consolidated into bulk ceramics by hot pressing at 1300–1450 °C sintering temperature and 60 MPa pressure. Tetragonal zirconia polycrystals obtained from the different powder technology processes differ considerably in phase composition, microstructure and mechanical properties. The laser vaporized derived materials are predominantly tetragonal, hard and combine high strength with a moderate toughness. The solid state synthesized materials show a transition to higher hardness and strength and lower fracture resistance with increasing sintering temperature, which can be correlated to the changes in phase composition and microstructure.