Higher fracture toughness of tetragonal zirconia ceramics through nanocrystalline structure

Fracture toughness of nanocrystalline zirconia ceramic stabilized with 1.5 mol.% Y2O3 was measured and compared with fracture toughness of submicrometer-grained zirconia ceramics stabilized with 3 mol.% Y2O3. It was found that nanocrystalline ceramics demonstrated higher fracture toughness than submicrometer-grained zirconia ceramics with both optimized and common grain sizes. The high fracture toughness of nanocrystalline zirconia was confirmed by two different testing methods: indentation method (15.5 MPa m0.5) and chevron notched beam method (7.9 MPa m0.5).