Effect of Al2O3 and Yb2O3 on Mechanical Performances and Thermal Shock Behaviors of Zirconia Composites Prepared by SPS

ZrO₂–Y₂O₃ composites with different content of Al₂O₃–Yb₂O₃ additives were fabricated by spark plasma sintering (SPS). The effect of Al₂O₃ and Yb₂O₃ additives on the mechanical performance, phase transformation, thermal shock resistance and microstructure of ZrO₂–Y₂O₃ composites was researched. The addition of Al₂O₃ and Yb₂O₃ contributed to enhancing the phase transformation and densification of ZrO₂–Y₂O₃ composites fabricated by SPS. ZrO₂–Y₂O₃ composites possessed the optimum comprehensive performances as the content of Al₂O₃ and Yb₂O₃ is 10 and 4 wt %, respectively. The thermal shock resistance (TSR), hardness, toughness, strength and relative density could achieved of 344°C, 13.6 GPa, 5.7 MPa m^1/2, 900 MPa, and 99.5%. The combination of refinement of grain size, changing of fracture mode, enhancement of density, phase transformation contributed to the improvement in TSR and mechanical performances of ZrO₂–Y₂O₃ composites fabricated by SPS.