燃烧条件对自蔓延高温合成Al2O3/AlB12复相陶瓷粉体特性的影响

以铝、B₂O₃为原料，利用自蔓延高温合成（SHS）制备了Al₂O₃／AlB₁₂复相陶瓷粉体，研究了燃烧条件对粉体特性的影响．结果发现，经球磨处理后，复相陶瓷粉体中Al₂O₃的平均粒径为3～4μm，AlB₁₂的粒度为亚微米级．粉体的比表面积为～1m²／g．燃烧过程中B₂O₃易于挥发，并在合成产物的表层生成B₂O₃和9Al₂O₃·2B₂O₃副产物相．在较低压力的氩气中进行合成，可以减少副产物相，获得纯度较高的复相陶瓷．与实际测量的燃烧温度对比发现，按照化学反应式13Al＋6B₂O₃＝6Al₂O₃＋AlB₁₂，通过热力学计算得到的绝热燃烧温度明显偏高．

Effects of Combustion Conditions on the Characteristics of Al2O3/AlB12 Composite Powders Produced by Self-Propagation High-Temperature Synthesis

Al₂O₃/AlB₁₂ composite powders were produced by self-propagation high-temperature synthesis (SHS) employing Al and B₂O₃ as initial reactants. The effects of combustion conditions on the characteristics of the powders were discussed. The results show that, Al₂O₃ has an average particle size of 3～4μm , while the size of AlB₁₂ is in the submicron range. The composite powders have an average specific surface of ～1 m²/g. Impurities of B₂O₃ and 9Al₂O₃.2B₂O₃ can be observed at the surface of the products because of the evaporization and condensation of B₂O₃. By decrease the argon pressure in the reactor, Al₂O₃/AlB₁₂ powders of high purity can be obtained. The adiabatic temperature of the reaction 13Al+6B₂O₃=6Al₂O₃+AlB₁₂ obtained from thermodynamic calculations is significantly higher than the measured combustion temperature.