The Effect of Zirconia Content on Physical and Mechanical Properties of Al2O3/ZrO2 Composites

The structural, physical and mechanical properties of alumina composites reinforced with various zirconia contents were studied. Zirconia with specific stress-induced toughness mechanisms (from tetragonal to monoclinic) can improve its mechanical properties. The raw materials were commercial products of alumina (Al2O3) and zirconia (ZrO2) with gamma alumina (γ-Al2O3) and monoclinic zirconia (m-ZrO2) phases, respectively. In this study, alumina and zirconia powders containing 0, 10, 20, 30, and 40 wt% were mechanically activated and sintered at 1400°C for 3 h. Fourier transform infrared spectroscopy (FTIR) characterization was used to confirm the functional groups in the sample. Phase analysis of the sintered samples was carried out via X-ray diffraction (XRD). Composite characterization includes diameter shrinkage, density, and Vickers hardness. Corundum (α-Al2O3), monoclinic zirconia (m-ZrO2) and tetragonal zirconia (t-ZrO2) phases were the observed phases in the sintered sample. The Al2O3/ZrO2 60:40 sample had the largest shrinkage in pellet diameter, apparent density, and Vickers hardness, at 8%, 4.35 g/cm3, and 1.33 HVN, respectively.