ASSESSMENT OF OXYGEN IN SILICON-CARBIDE FIBERS

Five different types of SiC fibre produced by chemical vapour depositi on were analysed using Auger electron spectroscopy (AES), scanning ele ctron microscopy (SEM) and X-ray (WDX) analysis. Fibres studied includ e SCS0, SCS6, Sigma SM1240 and two types of SIC fibres denoted SAM1 an d SAM2, produced in the Commonwealth of independent States (Ukraine, f ormer USSR). Fibres were fractured in situ in the Auger spectrometer. For each fibre, the oxygen, carbon and silicon yields were measured an d qualitative assessment of oxygen was performed. Results suggest that the SCS0 fibre contains less oxygen than other SIC fibres. It was rev ealed that the SAM1 fibre (120 mu m diameter) has a duplex SiC and car bon coating deposited over a 20 mu m tungsten core prior to the main S IC deposition, to decouple mechanically the tungsten core from the mai n SiC deposition.