Thermal conductivities of YSZ/Al_2O_3 composites

摘要

The thermal conductivities/diffusivities of YSZ/Al_2O_3 composites have been investigated by a laser flash technique. The thermal conductivity of the composite increases with an increase in the Al_2O_3 volume fraction, and it can be fitted well to the Maxwell theoretical model. The consistency of the thermal conductivities of the composites with the predicted values indicates the absence of obvious interfacial thermal resistances in the composites. The negligible thermal resistance effect from the YSZ and Al_2O_3 grain boundaries is due to the much lower phonon mean free path compared with the grain size in the composite. The low Kapitza resistance of the YSZ/Al_2O_3 interface is discussed in terms of the “clean” and coherent nature of the YSZ/Al_2O_3 interface, together with the small difference between the elastic properties of YSZ and Al_2O_3.