Anti-oxidation Protection Of Carbon Materials And The Preparation Of C/C Composite Material

Carbon materials is a class of non-metallic solid materials, which includes carbon and graphite materials. It is mainly including carbon fiber, carbon anode, graphite anode and special graphite, etc., it is widely used in aviation, aeroapace, electronics, chemical, nuclear industry, sports equipment etc, which has light weight, good electrical conductivity, thermal conductivity, corrosion resistance and heat resistance. However, the material begins oxidation at about400℃, which greatly limits its application in an oxidizing atmosphere. Therefore, in order to give full play to its excellent performance, the anti-oxidation protection of carbon materials is very important. C/C composites based on graphite or carbon fiber as reinforcement, graphite or carbon as matrix of composite materials, it widely used in aviation, aerospace and biomedical and other fields, which has low density, good ablation resistance, excellent friction properties and good biocompatibility.In this study, boron nitride coatings were deposited on carbon material by chemical vapor deposition, which study different temperatures and dipping-heat treatment times for impacting on the BN coating anti-oxidation resistance of carbon materials, obtain optimum parameters of preparing BN coating.The results show that the temperature is800℃, dipping-heat treatment times is3times and holding time is2h, which is the optimum parameters of preparing BN coating on three kinds of carbon material. Oxidation test showed that the initial oxidation temperature of the coated material as: carbon felt——550℃, graphite fiber felt composite——550℃and carbon slab——500℃; The initial oxidation temperature of the substrate materials as:carbon felt——450℃, graphite fiber felt composite——400℃and carbon slab——400℃.After the anti-oxidation properties of three kinds of carbon materials with BN coating tested by the sane temperature and dipping-heat treatment times, which found the anti-oxidant properties of carbon felt.is best, graphite fiber felt composite is worse, carbon plate is worst, which the structure and the density matrix of the carbon material.By the same temperature and immersion antioxidant properties after heat treatment under preparation three times the carbon coating materials tested come:Antioxidant properties of carbon felt best, composite mat, followed by the worst carbon plate, which the structure and the density matrix of the material.The experiment based on carbon plate as perform, nitrogen as the carrier gas and liquefied petroleum gas as carbon gases, which select the deposition temperature, the ratio of liquefied petroleum gas and nitrogen and deposition time. It used orthogonal test in the condition of vacuum and obtained the preparation of C/C composite optimum parameters on carbon plate.The results show that the effect of the ratio of liquefied petroleum gas and nitrogen on the percentage of weight gain was the most significant, prior to deposition temperature and deposition time; the deposition temperature is1000℃, the ratio of liquefied petroleum gas and nitrogen is1:3, deposition time is9h, which is the preparation of C/C composite optimum parameters on carbon plate.