Pressureless sintering of yttria-gadolinia co-stabilized zirconia

Abstract

Zirconia ceramics partially stabilized with yttria and gadolinia [(3-x)Y,xGd-TZP; x = 0–2] were manufactured by intensive co-milling of zirconia and stabilizer oxides, spray granulation, axial pressing and pressureless sintering at 1300–1400 °C. Microstructure, phase composition and mechanical properties were determined. Stabilizer re-distribution in the materials at higher sintering temperatures was monitored by XRD. Substitution of yttria for gadolinia reduces the stabilizer content in the tetragonal phase, increases the tetragonality of the materials and induces higher transformability and toughness. The hardness is thereby reduced. In accordance with thermodynamic considerations the cubic content increases with increasing gadolinia content.