Effect of alumina content on the mechanical properties of alumina-toughened calcia-stabilized tetragonal zirconia ceramic made of baddeleyite

Alumina-toughened calcia-stabilized tetragonal zirconia ceramics are produced using baddeleyite as raw material. A 3 wt.% CaO-ZrO2/Al2O3 ceramic containing 15 wt.% Al2O3 is characterized by sufficiently high mechanical properties: a hardness of 12.6 GPa, Young’s modulus of 248 GPa and fracture toughness of 10.3 MPa⋅m0.5. The hardness and Young’s modulus of this ceramic exceed those of alumina-free 3 wt.% CaO-ZrO2 ceramic by about 8.6% and 9.3%, respectively. However, fracture toughness of the prepared composite ceramic is lower than that of 3 wt.% CaO-ZrO2 ceramic by about 13.7%. It is revealed that in the fabricated 3 wt.% CaO-ZrO2/Al2O3 ceramic in the range of used Al2O3 concentrations transformation toughening prevails over residual stress toughening and crack deflection toughening.