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无机材料学报

无机材料学报

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高压气-固自蔓延高温合成h-BN-SiO2陶瓷材料的研究

陈贵清; 韩杰才; 张宇民; 张卫方; 杜善义   

  1. 哈尔滨工业大学复合材料研究所; 哈尔滨 150001
  • 收稿日期:1998-08-11 修回日期:1998-10-05 出版日期:1999-06-20 网络出版日期:1999-06-20

Investigation of High Pressure Gas-solid Self Propagating High Temperature Synthesis h-BN-SiO2 Ceramics

CHEN Gut-Qing; HAN Jie-Cai; ZHANG Yu-Min; ZHANG Wei-Fang; DU Shan-Yi   

  1. Center for Composite Materials; Harbin Institute of Technology Harbin 150001 China
  • Received:1998-08-11 Revised:1998-10-05 Published:1999-06-20 Online:1999-06-20

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摘要： 采用高压气-固自蔓延高温合成法制备了密度为179g／cm3的h－BN－SiO2陶瓷，其抗弯强度和硬度分别为76MPa和212（HV），分析了氮气压力和初始孔隙率对反应物点燃和产物的影响，结果发现在适当的初始孔隙率和氮气压力条件下(48%≤ρ≤52%, 75MPa≤ρ≤(85MPa)可以得到没有裂纹的产物．产物中的片状h－BN颗粒为各向同性，高的氮气压力导致h－BN颗粒尺寸较大，同时发现产物中SiO2以玻璃相的形式存在于晶相B7O的边缘，B7O的产生与原料SiO2及其氧化物杂质有关．

关键词: h－BN－SiO2陶瓷, 高压气-固自蔓延高温合成

Abstract: h-BN-SiO2 ceramics were prepared by means of high pressure gas-solid self-propagating high temperature synthesis technology from powders of B, h-BN
and SiO2. The nitrogen pressure and porosity of reactants that influence on ignition, and products have a scope, 48%≤ρ≤52%, 75MPa≤ρ≤85MPa, in which
the non-cracked combustion products can be obtained. The density of product is up to 1.79g·cm-3 and the bending strength and hardness of h-BN-SiO2 ceramic
are up to 76MPa and 212(HV) respectively. The higher the nitrogen pressure, the bigger the h-BN particles. The h-BN particles are isotropy. Crystalline B7O and glasses
SiO2 exist in the product. Crystalline SiO2 was disappeared because of rapid cooling from combustion temperature to 1000℃. Glass’s phases that are not
found among the h-BN particles only exist at the edge of B7O, which demonstrates that SiO2 is the cause of B7O formation.

Key words: h-BN-SiO2 ceramics, self-propagating high temperature synthesis

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