三维编织C/SiC纤维复合块材的XPS研究

用常规XPS、小面积XPS和成象XPS研究了三维编织的C/SiC纤维复合材料.结果表明，在燃气中灼烧后材料表面生成的暗红色反应是由于层中的SiC已氧化成氧化硅,同时反应层中还引入了杂质Fe、Na、Ca和Al；在反应层下Si以元素Si、SiC和氧化硅多种形式存在.块材横截面的多点小面积XPS分析结果表明，元素硅的相对浓度随深度增加而减少, SiC的相对浓度则随深度增加而增加.块材横截面的成象XPS分析清楚地显示了SiC 在纤维束边界间呈大致均匀的分布,在块材两边元素Si的浓度明显偏高.根据XPS象的线性扫描结果估计了纤维束、束间SiC层和块材边缘元素Si富集层的厚度.

XPS Study of Three Dimensional C/SiC Composites

The three dimensional carbon fiber reinforced SiC composites (C/SiC) were studied by using XPS,small area XPS and imaging XPS.The results show that Si in surface layer of the composites is oxidized to silicon oxides.The impurities of Fe,Na,Ca and Al are present after heating the composites in combustion gas at 1300 ℃. Beneath the surface layer,silicon is present in the forms of elemental Si,SiC and Si oxides in which elemental Si is produced by infiltration of molten silicon.The results of small area XPS multipoint analyses for the cross section of composite show that the relative content of elemental Si decreases with increasing distance from the cross section edge while the relative content of SiC increases with increasing the distance.The Si 2p XPS images show clearly that SiC is deposited in the boundary region between carbon fiber bundles.However,the content of elemental Si is higher in the margin area than in the center area of the cross section.The thickness of SiC between carbon fiber bundles in the center area and the thickness of elemental Si rich layer in the margin area of the cross section have been estimated by using the line scans of the XPS images.