X-RAY PHOTOELECTRON SPECTROSCOPIC STUDY OF THE EFFECT OF ION ETCHING OF SILICON-CARBIDE ON A CARBON-FIBER

Silicon carbide (SiC) was chemical vapor deposited (CVD) onto a carbon fiber to investigate oxidation protection of the coating. This thin film of SiC was analyzed before and after argon and oxy gen ion beam etching with core and valence band X-ray Photoelectron Spectroscopy (XPS). The valence band of SiC could be reasonably interpreted by a spectrum generated by a multiple scatter-wave Xa calculation. Oxygen ions were found to oxidize the coating to SiO2, whereas argon ion etching was found to thin and damage the SiC coating. The SiC coating was found to be susceptible to implantation of argon ions at energies of 6-8 keV, and was also mechanically damaged, causing the exposure of the underlying fiber after etching for up to 10 minutes. The topographical changes associated with argon ion etching were determined using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). We conclude that SIC may have some significant advantages in oxidation protection as compared to silicon nitride.