Microstructure and mechanical properties of ZrO2 ceramics toughened by 5–20 vol% Ta metallic particles fabricated by pressureless sintering

ZrO2-based composites toughened by 5, 10, 15 and 20 vol% lamellar shape Ta metallic particles were made by pressureless sintering. The microstructure and mechanical properties of these novel ceramic–metal composites have been studied. With only 15 vol%, the toughness of ZrO2–Ta composites was increased from 9.1 of monolithic zirconia to 14 MPa m1/2 and the average bend strength was 700 MPa. Our results have demonstrated that zirconia transformation and ductile phase toughening concepts can get together to enhance the fracture toughness of zirconia-based materials with high strength.