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利用化学气相沉积(CVD)法制备了Si-B-C陶瓷涂敷改性的2DC/SiC复合材料,研究了其在700~1200℃氧化10h性能和结构的演变规律以及自愈合机制,同时获得了Si-B-C涂层在不同温度氧化后的形貌、组分和物相转变规律。结果表明:涂敷在复合材料表面的Si-B-C陶瓷随温度的升高氧化加快,但氧化程度较低,不深于7μm;随温度的升高,氧化形成的硅硼玻璃黏度降低,挥发增强;当温度达到1200℃时,硅硼玻璃析出SiO2晶体;Si-B-C陶瓷涂敷改性的C/SiC具有优良的抗氧化性能,随氧化温度的升高,复合材料失重率增加,但在1200℃氧化10h后失重率仅为0.47%;此外材料在1000℃氧化后的强度保持率最高,达到91.6%,Si-B-C陶瓷氧化形成的硅硼玻璃可以有效封填裂纹,这是材料具有优良抗氧化性能的主要机制。
Si-BC ceramic coated modified 2DC / SiC composites were prepared by chemical vapor deposition (CVD) method. The properties and structure of the modified 2DC / SiC composites were studied at 700-1200 ℃ for 10h, and the self-healing mechanism was also obtained The morphology, composition and phase transformation of Si-BC coatings after oxidation at different temperatures. The results show that the Si-BC ceramics coated on the surface of composite material accelerate the oxidation with the increase of temperature, but the oxidation degree is lower than 7μm. With the increase of temperature, the viscosity of Si-BC ceramics decreases and the volatility increases ; When the temperature reaches 1200 ℃, the SiO2 crystals are precipitated in the borosilicate glass; the C / SiC modified with Si-BC ceramic has excellent oxidation resistance. With the increase of the oxidation temperature, the weight loss of the composites increases. ℃ after oxidation for 10h, the rate of weight loss is only 0.47%. In addition, the strength retention rate of the material after oxidation at 1000 ℃ is the highest (91.6%). Borosilicate glass formed by the oxidation of Si-BC ceramics can effectively seal the cracks, which is the material with excellent resistance The main mechanism of oxidation performance.