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应有X—射线光电子能谱(XPS)、俄歇电子能谱(AES)等电子能谱和热重分析(TG)、X—射线衍射(XRD)等物理方法,考察了由聚碳硅烷法制备的连续SiC纤维的表面性质,比较了不同的预处理条件对纤维表面组成、结构和性质的影响。结果表明,SiC纤维表面涂层可经500℃热处理或丙酮浸渍脱除;其体相结构为超细的β—SiC微晶结构,其表面存在硅氧化合物层,可能为α—SiO_2结构。在空气中500℃焙烧时,随着焙烧时间增长,表面氧化硅层增厚,同时表面游离碳含量减小。SiC纤维表面层硅氧化合物对酸较稳定,但易溶于热的浓碱。
X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and other electronic spectroscopy and thermogravimetric analysis (TG), X-ray diffraction (XRD) and other physical methods were investigated by the polycarbosilane method The surface properties of the prepared continuous SiC fibers were compared, and the effects of different pretreatment conditions on the surface composition, structure and properties of the fibers were compared. The results show that the SiC fiber surface coating can be removed by heat treatment at 500 ℃ or acetone impregnation. The bulk structure of the SiC fiber is an ultrafine β-SiC microcrystalline structure with a layer of silicon oxide on the surface, which may be α-SiO 2. When calcined at 500 ℃ in air, the surface silicon oxide layer thickens with the increase of calcination time, and the surface free carbon content decreases. Silicone compounds on the SiC fiber surface are more stable to acids but are more soluble in hot concentrated alkali.