Thermal properties of zirconia toughened alumina ceramics with boron nitride nanotubes

Abstract

The demand for high thermal conductivity substrates with electrically insulating materials are increasing with the emerging markets in power electronics and mobile telecommunication device packages. Effective heat transfer in those packages is important to provide high performance and reliability of the product. This paper presents the microstructure and thermal properties of zirconia toughened alumina ceramics with the addition of small amount of boron nitride nanotubes, BNNTs. The effect of the addition of BNNTs on the sintering behavior, the microstructure and the thermal conductivity of the zirconia toughened alumina, YZTA, nanocomposite ceramics are investigated. The thermal conductivity of YZTA ceramics decreased dramatically with the amount of zirconia contents due to relatively low thermal conductivity of zirconia ceramic. However, the addition of BNNTs less 0.5wt% to the YZTA ceramics slightly increased the thermal conductivity but decreased the coefficient of thermal expansion about 20%. The structure properties relation on this composite system is discussed.