关键词: AlN陶瓷, 低温烧结, 冲击处理, 位错, 晶粒畸变

Abstract: AlN powder was treated by shock waves with pressure of 9.8GPa. X-ray line broadening effect was found as the result of strain stored in shocked AlN lattice. Estimated
value of the strain is 2.85×10^-3, related dislocation density in shocked AlN powder is in the order of 10¹¹/cm², the energy stored in shocked
powder is 0.36Cal/g. The low temperature pressureless sintering process and thermal conductivity of shocked AlN powder with 6wt% additives were investigated. The results
showed that, the dislocation in shocked AlN powder can promote low temperature sinetring. In addition, it can remove Al₂O₃ from AlN lattices and achieve high thermal conductivity.
The energy stored in the shocked powder was released during the sintering process. The temperature of maximum shrink rate of shocked sample was about 25℃ lower than
that of unshocked one. The density of the shocked sample sintered at 1610℃ for 4h was 98% of its theoretical value, compared with 80% of the unshocked one. The
dislocation in shocked AlN powder can provide paths for the diffusion of oxygen through the grain in sintering process. So besides dissolution-reprecipitation, dislocation-
enhanced diffusion contributes its efforts to sintering, and it is beneficial for both sintering and achieving high thermal conductivity. The dislocation then can recover
in the later stage of the sintering process.

Key words: AlN, low-temperature sintering, shock waves treatment, dislocation, microstrain