DEVELOPMENT OF NOVEL PREPARATION PROCESS OF MICRO-COILED CARBON FIBERS AND TiC FIBERS

以含少量噻吩为杂质的乙炔为原料，采用不同类型的反应器进行金属催化热解，制备了微卷曲碳纤维。对制备的碳卷的反应条件和一些性能进行了测试。然后对碳卷进行气相钛化制备了微卷状TiC纤维，并对反应条件和部分性能进行了测试。所得结果总结如下：(A)碳微线圈的制备及性能：(1)设计了多气源入口的新型反应器，以获得大量的碳线圈样品。反应时间为2小时，线圈产率可达20 mg/cm^2。(2)使用lnconel公司生产的反应器，反应器表面形成了大量的碳质沉积物，线圈产率仅为1-3mg/cm^2-基质。金属铁对碳卷的生长有负面影响。(3)采用直径100 mm、长1000 m、多气源入口的新型大型反应器，可获得50g/d的线圈样品。(4)乙炔是获得碳盘管的唯一气源。以丙烷为气源，通过丙烷热解生成乙炔，得到少量不规则盘绕形状的碳盘管。(5) Ta205、Nb205、NiO等金属氧化物和金属元素对碳卷材的生长具有催化活性。(6)在衬底上施加过孔电压对碳线圈的生长有较强的影响，线圈的成品率提高到不加过孔电压时的1.5-2倍。(7)碳卷是一种非晶态材料，但在CO+CO2气氛中，在3000℃下热处理6小时后可以实现石墨化。(B)微卷曲TiC纤维的制备及一些性能：(1)在TiCI4+H2气氛下，碳卷在800-1200“*”C的温度下可以很容易地初始化，且充分保留了卷曲形貌。(2)采用非常规则卷曲的碳纤维作为源线圈，随着反应的增加，线圈的卷曲模式逐渐消失，然后消失，在纤维轴上形成具有连续亚微米直径孔的直纤维。(3) TiC微线圈/微管的体电阻率根据体密度和Ti/C比值的不同，在0.1 ~ 0.01 cm之间。少

Micro-coiled carbon fibers were prepared by the metal catalytic pyrolysis of acetylene containing small amounts of thiophene as an impurity using various type reactors. The reaction conditions and some properties of the obtained carbon coils were examined. And then, micro-coiled TiC fibers were obtained by the vapor phase titanizing of the carbon coils, and the reaction conditions and some properties were examined. The obtained results can be summarized as follows(A) Preparation and properties of carbon micro-coils :(1) New reactor with multiple source gas inlets were devised to obtain large amount of carbon coil samples. Coil yield of 20 mg/cm^2-substrate could be obtained for 2-hr reaction time.(2) Using the reactor made by lnconel, large amounts of carbonaceous deposits were formed on the surface of the reactor, and the coil yield was only 1-3mg/cm^2-substrate. Iron metal showed the negative effects the growth of carbon coils.(3) Using novel large reactor of 100 mm diam. and 1,000 m … More m long with multuple source gas inlets, the coil samples of 50g/day could be obtained(4) Acetylene was an exclusive source gas for obtaining carbon coils. Using propane as the source gas, small amounts of carbon coils with irregular coiling patterns was obtained via formation of acetylene by the pyrolysis of propane.(5) Metal oxides, such as Ta205, Nb205, NiO, as well as metal elements showed catalytic activities for growing carbon coils.(6) Application of vias voltage to the substrate showed strong effects the growth of carbon coils, and the coil yield increased to 1.5-2 times that of without vias voltage.(7) Carbon coils were an amorphous, but could be graphitized by the heat treatment at 3000 "*"C for 6-hr in CO+CO2 atmosphere.(B) Preparation of micro-coiled TiC fibers and some properties :(1) Carbon coils could be easily titinized at 800-1200"*"C under TiCI4+H2 atmosphere with full preservation of the coiling morphology.(2) Using very regular-coiled carbon fibers as a source coils, coiling patterns of the coils gradually disappeared with increasing reaction, and then disappeared to form straight fibers with continuous pores of submicron diameters in the fiber axis.(3) TiC micro-coils/micro-tubes have a bulk electrical resisitivity of 0.1-0.01 0cm depending on the bulk density and Ti/C ratio. Less