SBIR PHASE I: Combustion Chemical Vapor Deposition Processing of Lanthanum Phosphate and Beta-Alumina Fiber Coatings for Mullite Matrix Composites

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*** 9561712 Hunt This Small Business Innovation Research Phase I project will demonstrate the ability of Combustion Chemical Vapor Deposition (CCVD) to inexpensively deposit high quality lanthanum phosphate and beta-aluminate thin films for use in composite applications. A series of run studies will be performed to optimize the process and demonstrate reproducibility. In this project, thin films of lanthanum phosphate and beta-alumina will be grown onto flat substrates and fibers using CCVD. The composition, morphology, microstructure, and mechanical properties of the films will be determined as a function of deposition conditions. Combustion Chemical Vapor Deposition (CCVD~M) is the only open atmosphere CVD technique for ceramics. The CCVD method has been shown to inexpensively and quickly apply dense, adherent, epitaxial thin films in a continuous manner. This technology can be used for the production of lanthanum phosphate and beta-aluminate coated thermostructural composite fibers for stability and toughened behavior in mullite matrix composites. The CCVD method is low cost, high quality and versatile. It does not require a reaction chamber or furnace, yet the thin films produced are comparable in quality to CVD films, and allows fibers to be easily passed through a deposition zone for multi-layered, production line coatings. This firm has produced CVD quality films of numerous materials using CCVD in the open atmosphere. This allows for easy handling of fiber tows which is a major problem for other existing coating techniques. Traditional CVD coating of ceramic fibers is slow, difficult and expensive, and requires a specially designed furnace. In contrast, the CCVD technology offers the ability to coat multiple fibers without specialized equipment or environments. A large corporation has expressed interest in this technique for the production of low cost, high quality lanthanum phosphate and beta-aluminate films on fibers for high temperature protective and structural composites in mullite matrix composites. For these reasons, the CCVD technology is well-positioned to be used in the development of composites for fan blades, cylinder inserts, brake rotors and related applications. ***