无压烧结制备高致密度AlN-BN复合陶瓷

Fabrication of High Density AIN-BN Composite Ceramics by Presureless Sintering

以低温燃烧合成前驱物制备的比表面积为17.4m2／g的AIN粉末和市售BN粉末为原料,利用无压烧结工艺制备AlN-15BN复合陶瓷,研究了复合陶瓷的烧结行为以及制备材料的性能,结果表明:由于AlN粉末的烧结活性好,复合材料的烧结致密化温度主要集中在1500-1650℃之间,在1650℃烧结后,AlN-15BN复合陶瓷的相对密度可达95.6％。继续升高烧结温度,材料的致密度变化不大,热导率继续增加.在1850℃烧结3h后,可以制备出相对密度为96.1％,热导率为132.6W·m-1·K-1,硬度为HRA64.2的AIN-15BN复合陶瓷.提出了高比表面积的AlN粉末促进复合陶瓷烧结的机理,利用XRD,SEM等手段对烧结体进行了表征.

AlN-BN composite ceramics were produced by pressureless sintering process with BN powders bought from market and AlN powders having a specific surface area of 17.4m(2)/g synthesized from a combustion precursor, as starting materials. The sintering behavior and characterization of AlN-BN composite ceramics were studied. The results showed that the sintering temperature for densification was from 1500 to 1650degreesC because of the high sintering activity of AlN powders. AlN-15BN composite ceramics with relative density 95.6% were fabricated by sintering at 1650degreesC. The thermal conductivity of the composite ceramics was increased, while the density remained almost constant as sintering temperature increased. AlN-15BN composite ceramics with relative density 96.1%, thermal conductivity 132.6W(.)m(-1.)K(-1), and HRA hardness 64.2 were produced by sintering at 1850degreesC for 3h. The mechanism that high specific surface area AlN powders promoting the densification of AlN-BN composite ceramics was suggested, and the characterizations of the sintered bodies were determined by XRD, SEM and so on.