ムライトージルコニア複合セラミックスの熱伝導率

抄録

Thermal conductivity of mullite-zirconia composites was measured. Since the thermal conductivity of zirconia is smaller than that of mullite, the conductivity of composites gradually decreased with the addition of zirconia up to 30vol% into mullite, which is consistent with the results estimated from the Eucken's equation. However, it was remarkably lowered with the further additions and the minimum value, 3.26W·m^-1·K^-1, was attained at about 50vol% of zirconia fraction. In the ZrO₂-rich composites, on the other hand, a small decrease in conductivity compared to that of ZrO₂ was found in spite of the addition of higher conductive mullite. It has been supposed that the reaction occurred between yttria stabilizer and silica and/or alumina from mullite during sintering and it resulted in the formation of a glassy phase at the grain boundaries, which was responsible for the decrease in thermal conductivity.