SiC纤维在空气中的耐温性测试

Temperature Resistance Test of SiC Fiber in Air

SiC纤维作为SiC_(f)/SiC复合材料的重要承载部分,其耐温性能直接影响SiC纤维的实际应用。单丝拉伸强度和束丝拉伸力测试表明:在空气中,800℃时SiC纤维单丝强度维持在2.7 GPa以上,束丝拉伸力170 N以上,随时间延长无明显变化;温度升高至1000℃时,单丝强度下降至2.0 GPa,束丝拉伸力下降至159 N;超过1200℃后,纤维氧化明显,无长时间应用能力。其SEM及EDS结果表明,各个温度下纤维表面均有不同程度的氧化,温度越高纤维氧含量越高,超过1400℃时,纤维出现“皮芯”结构和脱落,氧化严重,完全失效。

SiC fiber is an important bearing part of SiC_(f)/SiC composite,and its temperature resistance directly affects the practical application of SiC fiber.The monofilament tensile Strength and tow tensile force test results show that the strength of SiC single fiber remains above 2.7 GPa and the tensile force of bundle is above 170 N in the air and without protection at 800℃,and there is no obvious change with the extension of time.When the temperature rises to 1000℃,the strength of monofilament decreases to 2.0 GPa and the tensile force of bundle fiber decreases to 159 N.After more than 1200℃,the fiber oxidation is obvious,and there is no long-term application ability.The SEM and EDS results showed that the surface of the fibers had different degrees of oxidation at different temperatures,and the higher the temperature was,the higher the oxygen content of the fibers was.When the temperature exceeded 1400℃,the“core skin”structure of the fibers appeared and fell off,and the oxidation was serious and complete failure.