화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.101, No.1, 334-346, 2018
Effect of point and planar defects on thermal conductivity of TiO2-x
In this study, we have investigated the effect of planar defect on thermal and electron transport as compared to point defect in the rutile TiO2-x. Two series of bulk TiO2-x (2-x = 2.000, 1.992, 1.985, 1.972, and 1.934) samples were prepared using different heat-treatment procedures to clearly identify the presence of point and planar defects via powder X-ray diffraction. The charge carrier density and mobility were determined from the Hall effect measurements using the van der Pauw method. The elastic properties of the studied materials such as bulk modulus, shear modulus, Young's modulus, compressibility, and Debye temperature were evaluated from the measured sound velocities, while their thermal conductivities were determined from the thermal diffusivities, heat capacities, and densities measured in the temperature range between 300 and 1073 K. The theoretical calculation based on Klemens-Callaway model has been performed to analyze the thermal conductivity. As a result, the effect of planar defects on the carrier mobility was almost equivalent to the effect produced by point defects. On the other hand, the presence of planar defects significantly reduced the thermal conductivity of TiO2-x as compared to point defect due to strong phonon scattering induced by planar defects.