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以六甲基二硅氮烷为先驱体,采用电热裂解化学气相沉积技术制备了以热解碳为界面的连续碳纤维增强SiCN陶瓷基复合材料(C/SiCN),并在不同温度和时间下进行了真空热处理。用扫描电镜、透射电镜、高分辨透射电镜、X衍射仪和光电分析天平分别进行微观观察、相变分析和质量测量。结果表明:热处理温度对基体晶化程度的影响要比增加热处理时间的影响更明显;非晶SiCN基体经1100℃热处理30h后已有微量β-SiC晶粒产生;在1100℃,30h;1300℃,30h;1500℃,30h和1700℃,2h热处理后,部分SiCN转变为SiC,没有发现Si3N4;1700℃热处理2h后,晶粒间的非晶SiCN内出现层状石墨;1900℃热处理0.5h后,SiCN基体几乎全部晶化,并明显出现Si3N4晶体;在1100℃到1300℃真空热处理30h后,质量损失主要是H–的损失;在1500℃到1900℃处理后,除了H–损失之外,还有部分N–损失。
Using hexamethyldisilazane as precursor, continuous carbon fiber reinforced SiCN ceramic matrix composites (C / SiCN) with pyrolytic carbon as the interface were prepared by electrothermal pyrolysis chemical vapor deposition (CVD) technology and were subjected to different temperature and time Vacuum heat treatment. The microscopic observation, phase change analysis and quality measurement were carried out by scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, X-ray diffractometry and photoelectric analytical balance respectively. The results show that the influence of heat treatment temperature on the degree of crystallization is more obvious than that of heat treatment. The amount of β-SiC grains is increased after heat treatment at 1100 ℃ for 30h, and at 1100 ℃, 30h and 1300 ℃ , 30h, 1500 ℃, 30h and 1700 ℃ for 2h, part of SiCN was transformed into SiC and no Si3N4 was found. After heat treatment at 1700 ℃ for 2h, layered graphite appeared in the intergranular amorphous SiCN. After heat treatment at 1900 ℃ for 0.5h , The SiCN matrix crystallizes almost completely and the Si3N4 crystal appears obviously; the mass loss is mainly the loss of H- after the vacuum heat treatment at 1100 ° C to 1300 ° C for 30h; after the treatment at 1500 ° C to 1900 ° C, in addition to the H-loss, There are some N-losses.