(哈尔滨工业大学复合材料研究所,哈尔滨 150001)
摘 要: 采用高压气-固自蔓延高温合成技术制备了产物密度为1.70 g/cm-3的六方BN(h-BN)陶瓷,其最高抗弯强度和硬度分别为42.8MPa和108(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,发现在适当的初始孔隙率和氮气压力条件下,可以合成没有裂纹的h-BN陶瓷产物,其范围为:48%≤ρ≤52%,95 MPa≤p≤110MPa。同时发现产物中的片状h-BN颗粒为各向同性,h-BN产物纯度较高,在高的氮气压力条件下合成的h-BN颗粒较大。片状h-BN颗粒内部出现分裂和弯折等现象。
关键字: h-BN陶瓷;高压;气-固反应; SHS
(Center for Composite Materials, Harbin Institute of Technology, Harbin 150001,P.R.China)
Abstract: h-BN ceramics were prepared from powders of B and h-BN by means of high pressure gas-solid self-propagating high temperature synthesis technology. The density of h-BN ceramics is 1.70 g/cm-3, the bending strength and the hardness of h-BN ceramics were 42.8 MPa and 108(HV) respectively. The nitrogen pressure and porosity of reactants that influence ignition and products have a best scope, 95 MPa≤p ≤110 MPa, 4 8%≤ρ≤52%, in which the steady combustion products can be obtained. By X-ray diffraction, scanning electron microscopy and transmission electron microscopy, the phase and microstructure were analyzed. The higher the nitrogen pressure , the larger the h-BN particle. The distribution of h-BN particles is anisotropic. There are branches and twists in the h-BN particles.
Key words: h-BN ceramics; high pressure; gas-solid reactions; SHS