以一甲基三氯硅烷为先驱体原料(MTS),H2气为载气,采用化学气相沉积(CVD)工艺,在Si基体表面制备SiC膜层。利用XPS、XRD、SEM以及HRTEM等表征方法,研究当沉积为SiC+C时,游离碳对SiC膜层微观结构及其力学性能的影响。结果表明,膜层由SiC和C两相组成,形成SiC/C复合膜层结构,游离碳引起SiC晶粒细化。在SiC/C膜层中,游离碳的石墨化程度低,主要以无定形结构存在于SiC晶粒之间,形成富C区。由于SiC膜层中含有富C区,填充了SiC晶粒之间缺陷,这有利于提高SiC膜层的机械强度,以及改善SiC/Si之间的晶格匹配。

SiC was deposited on the surface of Si substrate by chemical vapor deposition technique,with methyltrichlorosilane (MTS)as the SiC gaseous source and H2 as carrier gas respectively.The effects of the free carbon on microstructure of SiC film were investigeted by X-ray diffraction( XPS) ,X-ray diffraction( XRD) ,scanning electron microscop( SEM) and high resolution transmis-sion electron microscope(HRTEM).The results indicate that the SiC/C composite film is consisted of SiC grains and amorphous car-bon mixed some graphite crystallites,which can reduce the grain size of SiC.In addition,the free carbon within SiC film was detected in the gap of SiC grains.The changes in microstrure can increase the mechanical strength of SiC film and improve the SiC/Si crystal lattice matching.

以316L不锈钢为基底,SiC晶体为靶材,Ar为源气体,采用磁控溅射法在不同温度下制备出系列SiC过渡层.然后以高纯石墨作靶,Ar和CHF_3为源气体,在同一工艺条件下再续镀一层氟化类金刚石(F-DLC)薄膜,形成SiC/F-DLC复合薄膜.研究表明,相比于F-DLC薄膜,复合薄膜的附着力显著增加,血液相容性明显改善.通过样品的拉曼和红外光谱分析了不同温度下制备的SiC过渡层以及复合薄膜结构的演变.结果表明,控制SiC过渡层制备温度可以有效调制过渡层中C=C键的比例以及—C—C—不饱和键的密度,复合薄膜中保留较高比例的芳香环式结构以及合适的F/C比是薄膜的血液相容性得以进一步改善的原因,SiC过渡层制备温度控制在500℃左右效果尤为明显.SiC薄膜和F-DLC两种薄膜的界面处形成一定比例的Si—C键和C=C键是导致复合薄膜附着力显著上升的直接原因.适当条件下在316L不锈钢和F-DLC薄膜之间增加SiC过渡层对于增强薄膜的附着力、改善其血液相容性是可行、有效的.

A series of SiC intermediate layers with different preparation temperatures is prepared by radio frequency magnetron sputtering on 316L stainless steel substrates by use of SiC crystal target and Argon as source gases. And then depositing fluorinated diamond-like carbon films (F-DLC) on a series of SiC intermediate layers under the same deposition condition with trifluromethane (CHF3) and Argon as source gases, and pure graphite as a target, a series of SiC/F-DLC composite films are obtained. The results show that the composite films have stronger adhesion and better hemocompatibility than that of the F-DLC films. The structure evolves with preparation temperatures of SiC intermediate layers and SiC/F-DLC composite films are studied by their Raman and Infrared transmission spectra. The results show that the proportion of C=C bonds and density of C-C unsaturated bonds in the SiC intermediate layers can be modulated by controlling the preparation temperature of SiC intermediate layers. T

提出了一种C/SiC复合材料的连接方法：在线气相穿刺连接。该方法是在C/SiC复合材料制备的最后一步--SiC沉积过程中，对待连接件进行C纤维束穿刺，穿刺后继续沉积SiC，最终在完成复合材料制备的同时，结束复合材料的连接过程。采用该方法，对2D和3D C/SiC复合材料进行了在线气相穿刺连接。结果表明：在线气相穿刺连接所得接头热物理和热化学相容性好，连接应力低，拉伸强度可达82 MPa，连接过程不影响构件的使用温度，是一种适合于纤维增韧陶瓷基复合材料的连接方法。

An on-line gas needling joining method was developed for C/SiC composites. The joining process was carried out during the last step of the C/SiC composite preparation--SiC deposition process, the puncture of C fiber bundle on the joining component was made, then the process of SiC deposition continued until the completion of the C/SiC composites preparation and the joining process finished. 2D and 3D C/SiC composites were joined with on-line gas needling joining process. The results show that the obtained joints have favorable thermal physical and thermal chemical compatibility. The stress at the joints is low and the tensile strength is high up to 82 MPa. The joining process doesn’t affect the employment temperature of the joining component, and is suitable for joining of fiber reinforced ceramic matrix composites.

碳陶(C/SiC)刹车材料是近年来发展的一种新型刹车材料,具有密度低、耐高温、摩擦性能高且稳定等优点,在高速列车、飞机等高能刹车领域具有广泛的应用前景。刹车材料是结构/功能一体化材料,纤维预制体结构对材料的热物理性能、摩擦磨损性能和力学性能有很大影响。针对不同预制体类型,对C/SiC刹车材料的制备、微结构和摩擦磨损性能进行了系统介绍。同时,介绍了C/SiC刹车材料的改性方法。

Carbon/silicon carbide (C/SiC) composites are new type of brake materials developed recently. C/SiC composites possess excellent properties, such as low density, good resistance to high temperature and high and stable frictional properties. C/SiC composites are promising brake materials in the ifeld of high energy such as high speed trains and aircraft. Brake materials are structural-functional integration materials. The structure of ifber preform has a great inlfuence on the thermo-physical properties, friction and wear properties and mechanical properties of materials. Preparation, microstructure and tribological properties of C/SiC with different performs are systematically introduced. Also, the modiifed methods of C/SiC brake materials are described.

以全网胎针刺整体毡为预制体,采用化学气相渗透法增密制备C/C多孔坯体。采用反应熔体渗透法,将Si粉,Ti粉和Cu粉均匀混合,在1 400~1 700℃下制备C/C-SiC-Cu5Si复合材料。利用X射线衍射分析该复合材料的物相组成,用扫描电镜分析其显微形貌。结果表明：C/C-SiC-Cu5Si复合材料由炭纤维,热解炭,β-SiC,TiC和Cu5Si相组成;生成的TiC相主要分布在热解炭周围,Cu5Si分布在TiC周围,而β-SiC弥散分布在Cu5Si基体中;TiC晶粒的形成是Ti原子向C原子扩散的结果,其长大受Ti原子扩散控制。

Carbon fiber reinforced carbon matrix composites were fabricated by chemical vapor infiltration (CVI) using short-cut fabric as preform. C/C-SiC-Cu5Si composites were fabricated at 1 400~1 700 ℃ by reactive melt infiltration (RMI) using the mixture of silicon powders, titanium powders and copper powders as molten materials. The phase composition and microstructure of C/C-SiC-Cu5Si composites were analyzed by XRD and SEM, respectively. The results show that, C/C-SiC-Cu5Si composites are composed of carbon fiber, pyrocarbon, β-SiC, TiC and Cu5Si; pyrocarbon is surrounded by TiC which is next to Cu5Si, whereas β-SiC is distributed uniformly in Cu5Si matrix; the formation of TiC crystalline grain is attributed to diffusion of Ti atoms to C, and its growth is dominated by diffusion of Ti atoms.