AlN添加量对BN基复合陶瓷热学性能与抗热震性的影响

Effects of AlN Content on the Thermal Properties and Thermal Shock Resistance of BN Matrix Composite Ceramic

以BN、SiO2、AlN为原料,采用热压工艺制备出BN基复合陶瓷。研究了AlN添加量对复合陶瓷热学与抗热震性能的影响。结果表明:随着AlN添加量的增加,复合陶瓷的热膨胀系数呈现先降低后升高的趋势。当AlN的添加量为5vol%时,复合陶瓷的平均热膨胀系数最小,为2.22×10-6/K;复合陶瓷的热导率则随着AlN添加量的增加呈先升高后降低的趋势,当AlN的添加量为10vol%时达到最大值。未添加AlN的复合陶瓷热震后的残余强度随着热震温差的增大而升高;随着AlN的引入,复合陶瓷热震后的残余强度呈下降的趋势。对于添加5vol%AlN的复合陶瓷,经1100℃热震后其残余强度为219.7 MPa,强度保持率为88.9%,抗热震性良好。

Using BN, SiO2, AlN as the raw materials, BN matrix composites ceramics were fabricated by hot-press sintering. Effects of AlN content on the thermal properties and thermal shock resistance of the composites were studied. It was found that thermal expansion coefficient of the composites decreased at first and then increased with the increase of AlN addition. When 5vol% AlN was used as the raw materials, the produced composite exhibited the minimum coefficient of thermal expansion, which was 2.22× 10^-6/K. Thermal conductivity of the composites increased at first and then decreased, and reached the highest value when 10vol% AlN was used as raw materials. The residual strength after thermal shock of the composites without AlN increased with the increase of thermal shock temperature difference. Residual strength of composite ceramic after thermal shock showed downward trend with the introduction of AlN. For composite ceramic adding with 5vol% AlN, the residual strength was 219.7 MPa and the residual strength was 88.9% after thermal shock from 1100℃ to ice water, showing a good thermal shock resistance.