摘要
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。
Two dimensional C/SiC composite coated with Si - B - C ceramic was prepared via chemical vapor deposition （CVD）. Properties and structure evolution and self-healing mechanisms of the C/SiC composite were studied after oxidation for 10 h during 700 - 1200℃. At the same time, the evolution of morphologies, composition and phase for Si - B - C ceramic were also investigated. The experimental results show that the oxidation of Si - B - C ceramic accelerates with the temperature increasing, however, the oxidation scale is shallow and no more than 7 gm. With the temperature increasing, viscosity of borosilicate glass oxidized from Si - B- C ceramic reduces but volatilization accelerates. When the temperature increases to 1200 ℃, SiO2 crystallizes from borosilicate glass. C/SiC composite coated with Si - B - C ceramic shows an excellent oxidation resistance. Mass loss increases with temperature increasing, which is only 0.47 % after oxidation for 10 h at 1200 ℃. Furthermore, the strength retention ratio is 91.6% at 1000 ℃, higher than that at other temperatures. The main mechanisms for excellent oxidation resistance of C/SiC composite is that borosilicate glass oxidized from Si B - C ceramic can seal cracks in composite effectively.
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2013年第3期100-106,共7页
Acta Materiae Compositae Sinica
基金
国家自然科学基金(51002120
51032006)
