中文摘要：

以甲基三氯硅烷为先驱体,用直流电热三级化学气相沉积法制备了带有碳涂层的钨芯SiC纤维,测定了纤维的室温拉伸强度,并用Weibull分布对纤维的拉伸强度进行了评价.利用扫描电镜（SEM）、X射线衍射仪（XRD）和透射电镜（TEM）分析了纤维的断口形貌、相结构组成和W/SiC界面反应层的微观结构.结果显示,三级化学气相沉积法制备SiC纤维拥有两层β-SiC和均匀的表面碳涂层,钨芯和SiC之间存在厚度约为0.35μm的界面反应层,纤维的平均拉伸强度和Weibull模数分别达到3266MPa和16.3,并对纤维的断裂机理进行了分析和讨论.

英文摘要：

Continuous silicon carbide（SiC） fiber with carbon coating was fabricated by three-stage chemical vapor deposition（CVD） on W filament heated by direct current（DC）,using CH_3SiCl_3 as gaseous reactant for SiC as well as C_2H_2 for the outmost carbon coating.Young＇s modulus and tensile strength of the fiber were tested at room temperature, while Weibull distribution was conducted for evaluation of the tensile properties of the fiber.Fracture morphology,phase structure and microstructure of the fiber were investigated by scanning electron microscope （SEM）,X-ray diffraction（XRD） and transmission electron microscope（TEM）.Results show that the SiC fiber, from W core to outside,exhibits a W/SiC interfacial reaction layer with a thickness of about 0.35μm,two layers of SiC and an even carbon coating.XRD pattern indicates that the SiC layers are all composed of P-SiC,which corresponds to diffraction angle of 35.6°,60.1°,72.1°and 75.7°.The mean tensile strength and Weibull modulus of the fiber reach 3266 MPa and 16.3,respectively.Furthermore,fracture mechanism of the fiber is discussed.