Reducing sintering temperature of yttria stabilized zirconia through addition of lithium nitrate and alumina

Reducing sintering temperature of yttria stabilized zirconia (YSZ) has been achieved through doping with alumina and lithium nitrate at levels below 1 mol%. Sintering experiments of pure and doped samples have been conducted with the same profile using an optical dilatometer. All samples exhibited anisotropic sintering over a wide range of temperatures but final shrinkage values were comparable in axial and radial directions. Sintering temperature has been reduced by as much as 110 °C. We believe that the reduction in sintering temperatures is due to viscous flow in the first stage sintering. Bimetallic doping (mixture of alumina and lithium nitrate doping) is more effective in reducing sintering temperature than single doping possibly due to better distribution of doping material throughout the matrix material. Separate sintering experiments for 5 h have been conducted at 1250 °C and 1170 °C on doped 8 mol% and 3 mol% YSZ, respectively, and have shown that near full density (∼96%) is reachable.