Abstract:

Mullite (3Al2O3.2SiO2) and 3 mol% yttria added zirconia (3 mol% Y2O3 - 97 mol% ZrO2) ceramic powders were synthesized by conventional ceramic processing route. All mixtures were prepared by mechanical alloying method in acetone environment with zirconia ball mill. Mullite and yttria added zirconia ceramic powders were synthesized by reaction sintering in air at 1600oC for 3h and 1300oC for 2h, respectively. The ceramic phases formed were made ready to form ceramic - ceramic composites by crushing, grinding and sieving processes. Then, 0 and 10% by weight mullite added yttria doped zirconia mixtures were prepared by powder metallurgy method. After drying, the powders were compacted by uniaxial pressing. The green compacts were sintered at 1500-1600oC for 1-5 h in air conditions in a high temperature furnace. Then, microstructure (SEM), phase analysis (XRD), mechanical (hardness, 3-point bending and wear) and physical properties (%shrinkage, water absorption, porosity and density) tests were performed on the composites. In this study, whether there is a phase change in the ZrO2-Y2O3 mixture at high sintering temperatures and the effect of mullite additive on the properties of this mixture was investigated. The data obtained were presented in graphs and tables and their comments were made.

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