Effect of Gd₂O₃ on the thermal conductivity of ZrO₂-4 mol.% Y₂O₃ ceramics fabricated by spark plasma sintering

Porous and dense ZrO₂-4 mol.% Y₂O₃ ceramics were fabricated by spark plasma sintering at 1100 and 1500 °C. The porosity of the ceramics sintered at 1100 °C increased with the addition of ∼0-5 mol.% Gd₂O₃. In contrast, the ceramics sintered at 1500 °C showed full density regardless of the amount of Gd ₂O₃ addition. The fluorite-type Gd₂Zr ₂O₇ phase was formed as the second phase in the tetragonal ZrO₂ matrix. The thermal diffusivity and thermal conductivity of sintered ZrO₂-4 mol.% Y₂O₃ decreased with increasing Gd₂O₃ addition.