New Reagents for CVD and CVI of Carbon Containing Boron and Other OxidationInhibitors

摘要

The objectives of this three-year project were to: (1) identify and evaluate newmultielement reagents to be used for the deposition of carbon containing one or more of the oxidation inhibitors boron and silicon, (2) determine the feasibility of the forced flow-thermal gradient CVI process for the rapid fabrication of carbon-carbon composites, and (3) understand the CVD of SiC and boron carbide and codeposition of these two phases since these materials have potential as oxidation protective coatings and matrices for carbon-carbon and other composites. Only satisfactory progress was made on objective No. 1, but excellent progress was made in regard to the other two objectives. Carbon-carbon was prepared in 3 h using the FCVI process and a thorough kinetics and deposit microstructure knowledge base was established for the CVD of SiC, boron carbide, and codeposition of these materials. A novel technique for monitoring the progression of densification during CVI was conceived and demonstrated. Importantly, a new class of materials, laminated matrix composites, was produced. jg.