Efficient Evaluation of Fiber Coatings

Development of a rapid technique based on FTIR spectroscopy to monitor chemistry, crystallinity and contamination of CMC interface coatings is proposed.The method takes advantage of specificity of vibrational normal modes of molecules, which can be utilized as fingerprints of molecules to evaluate chemistry of the coatings.A literature review of spectroscopic characteristics of molecules utilized as interface coatings confirms that FTIR spectroscopy has a high chance of successfully determining chemistry, and detection of contamination of the coatings.Understanding of crystal structure and determining levels of detection of contamination will require access to primary data such as Auger depth profiling and X-ray diffraction.Automated statistical methods based on chemometrics can be developed for industrial applications of the proposed analytical methods.The assurance of success of the proposed method is supported by SOCs years of experience in analysis of CMC coatings, and development of on-line and off-line instrumentation and methods to predict thickness (weight gain) of the interface coatings.The final success of this program will depend on close collaboration with the manufacturers of CMC coatings.SOC secured commitment of GE Aviation to provide samples of coated fibers to test the proposed methods in industrial environments of their fiber coating facilities.