金属钽掺杂聚碳硅烷制备TaC-SiC纤维研究

Preparation of TaC-SiC fibers derived from Ta-doped polycarbosilicon precursor

摘要:

本文以纳米级金属钽粉和聚碳硅烷为原料,通过超声和球磨混合得到了钽掺杂的SiC陶瓷先驱体,经熔融纺丝、电子束不熔化和高温烧成制备了连续TaC-SiC纤维。采用FT-IR、TG、XRD、SEM和EDS等表征了先驱体纤维的结构和热失重、陶瓷纤维的结构组成和微观形貌。结果表明金属钽的引入促进了PCS的交联,将先驱体的陶瓷产率提高到69.3wt%；金属钽通过与纤维中的富余碳反应生成TaC；所得TaC-SiC陶瓷纤维表面光滑、结构致密,具有优异的耐高温性能。该方法在制备TaC-SiC复相陶瓷纤维上有很好的应用前景。

Abstract:

In this work, preparation of TaC-SiC fibers derived from Ta-doped polycarbosilicon precursor are reported. Ta-doped precursor was prepared by using nanometer tantalum powders (nano-Ta) and polycarbonsilane (PCS), according to the quality of tantalum powders and PCS at 10wt%, via ultrasonic and ball mill mixing method. TaC-SiC fibers were prepared after melt-spinning, electron beam irradiation and heat-treatment. The composition, structure and pyrolysis process of the obtained green fibers were investigated by IR, TG, XRD, SEM and so on. The results show the evolution of volatile gases is inhibited via introduction of nano-Ta in the precursor and the yield of precursor was increased to 69.32 wt%. TaC ceramics could be prepared via reaction of tantalum powders with free carbon in the fibers. The ceramic fibers were compact and smooth. Thus, TaC-SiC fibers could be prepared using the doped method.