Influence of Heat Treatment in Sintering Process on Characteristics of Al₂o₃-Zro₂ Ceramics Systems

Al₂O₃-ZrO₂ ceramics containing 5-50 mol% ZrO₂ were prepared by solid state reaction method. The bulk density, average grain size and microhardness of Al₂O₃-ZrO₂ ceramics system as function of ZrO₂ content were investigated. The dense Al₂O₃-ZrO₂ ceramics were successfully by means of carefully control processing parameters that include sintering temperature and heating/cooling rates. These ceramics with higher ZrO₂ content was obtained high bulk densities and small grain sizes. However, the high hardness values were exhibited from Al₂O₃-ZrO₂ ceramics with dopants ZrO₂ between 1-10mol% and its tend to decrease with concentration of ZrO₂. It can be found that the fast heating/cooling rates are controlled grain growth and obtained high hardness in materials. The results gave good correlation between stoichiometry characteristics, heating/cooling rates in sintering and microstructure of fabricated dense and mechanical properties.