Abstract
The good thermal conductivity of AlN is essential for insulation and high heat dissipation applications. However, the influence of oxygen impurities at various locations (the lattice oxygen and grain edge oxygen) on the thermal resistivity of AlN ceramics is unclear. In this study, AlN ceramics with various oxygen distributions are prepared by different methods, and the oxygen contents of different regions are distinguished. The results indicate that the lattice oxygen is the main factor affecting thermal resistivity. Meanwhile, high-temperature annealing and pre-sintering processes can lower the lattice oxygen content from 0.061 wt% to 0.038 wt% and 0.036 wt%, respectively. Additionally, when grain edge phase volume is less than 4 vol%, it does not contribute significantly to thermal resistivity. The main formation of thermal resistance changes from phonon-defect scattering to phonon-phonon scattering with increasing temperature. These results may be informative for the microstructure design of AlN ceramics with high thermal conductivity.
Published Version
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