Densification and mechanical behaviour of zirconia containing flyash as dopant

Abstract

Abstract The densification and mechanical behaviour of tetragonal zirconia doped with up to 2 wt% flyash as dopant were studied. In this work, the dopant was blended with commercial 3 mol% yttria-stabilised zirconia powders by attrition milling. Sintering was accomplished by firing the green bodies at various temperatures ranging from 1250 ºC to 1500 ºC under atmospheric conditions. Sintered bodies were evaluated for bulk density, phase retention, elastic modulus, Vickers hardness and fracture toughness. An improvement in the zirconia properties in terms of bulk density, Vickers hardness and matrix stiffness were evident at low sintering temperatures for samples containing up to 0.5 wt% flyash. In contrast, the fracture toughness and tetragonal phase stability of the zirconia was not influenced by the dopant and sintering temperature. The addition of 1 wt% and 2 wt% flyash, however were not effective in enhancing the properties of the sintered zirconia. This study also found that the addition of flyash as dopant was beneficial in suppressing the low-temperature degradation kinetics of tetragonal zirconia in steam environment.