Influence of the rigid alumina particles added to ZrO 2 ceramics stabilized with Y 2 O 3 for its mechanical properties

4 MATERIAŁY ELEKTRONICZNE (Electronic Materials), 2019, 47, 1 4 The effect of the phase added to ZrO2 ceramics on its mechanical properties, and in partcular on the fracture toughness, was examined using the example of Al2O3 ZrO2 composite where ZrO2 was stabilized with 3 mol% of Y2O3. Composites of 20% wt. Al2O3 80 wt.% ZrO2 with different size of corundum grain were made. Vickers indenter crack resistance tests showed an increase of 21% in the value of this parameter for the samples with Al2O3 grains of approx. 6.5 μm in comparison with pure ZrO2 ceramics. On the basis of literature data and microscopic observations, authors present a thesis that this increase is caused by two factors, i.e. the increase of the phase transition range (from tetragonal to monoclinic phase) accompanying crack propagation and the effect of large Al2O3 grains as bridges fastening the fracture surfaces.