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利用反应磁控溅射法在SiC长纤维表面沉积了(Al+Al₂O₃)扩散阻挡涂层, 研究了沉积工艺参数对涂层的成分、沉积速率的影响, 以及涂层对SiC纤维的表面残余应力及力学性能的影响. 结果表明, 随着溅射功率的增加, Al₂O₃涂层的沉积速率先迅速增加后缓慢增加; 随着工作气压的增加, Al₂O₃涂层的沉积速率先缓慢降低, 在工作气压到达一定值时, 沉积速率快速下降随后缓慢下降. 沉积的(Al+Al₂O₃)复合涂层保护了SiC纤维的富C层, 起到了保证纤维与Al₂O₃涂层之间结合力的作用; 激光Raman谱显示改性后纤维的表面残余应力有降低趋势. 室温和高温处理后复合丝的拉伸强度分别是计算值的97.69%和98.77%, 涂层对纤维的力学性能影响很小.

Reactive magnetron sputtering was used to prepare (Al+Al₂O₃) diffusion barrier layer on SiC fiber surface. The relationships between deposition process parameters with composition and deposition rate of the coating, and the influence of the coating on mechanical property of SiC fiber were measured. Results show that with increasing sputtering power, the deposition rate increases rapidly at first and then slowly. With increasing of working pressure, the deposition rate of the coating deceases slowly at first, and then sharply at a typical value of working pressure, finally drops gradually. (Al+Al₂O₃) protected C-rich layer of SiC fiber, and improved the adherence between fiber and diffusion barrier layer. Results of laser Raman spectrum show that the coating has little influence on surface residual stress of SiC fiber. The measured tensile strength of the composite fibers is 97.69% of the calculated tensile strength according to meaning rule, and is 98.77% of the calculated one for the fiber after vacuum treatment at 850 ℃ for 10 h, meaning that (Al+Al$_{2}$O$_{3}$) coating has not much influence on mechanical property of SiC fiber.