High‐Toughness Ce‐TZP/Al ₂ O ₃ Ceramics with Improved Hardness and Strength

Abstract

Simulataneous additions of SrO and Al 2 O 3 to ZrO 2 (12 mol% CeO 2 ) lead to the in situ formation of strontium aluminate (SrO · 6Al 2 O 3 ) platelets (∼0.5 μm in width and 5 to 10 μm in length) within the Ce‐TZP matrix. These platelet‐containing Ce‐TZP ceramics have the strength (500 to 700 MPa) and hardness (13 to 14 GPa) of Ce‐TZP/Al 2 O 3 while maintaining the high toughness (14 to 15 MPa ± m 1/2 ) of Ce‐TZP. Optimum room‐temperature properties are obtained at SrO/Al 2 O 3 molar ratios between 0.025 and 0.1 for ZrO 2 (12 mol% CeO 2 ) with starting Al 2 O 3 contents ranging between 15 and 60 vol%. The role of various toughening mechanisms is discussed for these composite ceramics.