SIMS profiling and TEM of CVD films on multi-filament samples

A suitable fibre coating is essential to obtain optimal fibre-matrix intera ction in fibre-strengthened composite materials. Thin films (similar to 100 nm) of silicon carbide, turbostratic carbon, and boron nitride were deposi ted by CVD as single or double lavers on commercial multi-filament fibres i n a continuous process. The fibre material itself may be carbon, alumina, s ilicon carbide, or a quaternary ceramic of SiCBN. The application of MCs+-S IMS enables one to determine the composition (including impurities of H and O) of various fibre coating materials with an accuracy of at least 20% rel ative. Due to the special geometry of the multi-filament samples the depth resolution of the SIMS depth profiles is limited, nevertheless, layered str uctures and some details of the interface between coating and fibre can be studied. The depth calibration of the SIMS depth profiles is derived from s putter rates established on flat samples with a composition similar to that of the fibre coating material. However, the obtained film thicknesses are not extremely different from the values derived from TEM on cross sections of coated fibres.