Carbon fiber with Sibcn gradient coating deposited on the surface and preparation method thereof

Abstract

A carbon fiber with a SiBCN gradient coating deposited on the outside, including a carbon fiber substrate and a SiBCN gradient coating deposited on the substrate, the gradient coating and the substrate are combined by mechanical interlocking and chemical bonding, and the free carbon content in the gradient coating is from the inner Decrease to the outside; the gradient coating is prepared by chemical vapor deposition using borazine and liquid polycarbosilane as raw materials; the preparation method of the present invention includes: cleaning and drying the carbon fiber matrix material and putting it into a deposition furnace; Replace the air in the deposition furnace; preheat at the set vacuum degree and temperature, introduce diluent gas; control the mixing ratio of NH3 and H2 in the carrier gas, load borazine and liquid polycarbosilane into the deposition furnace, and deposit The SiBCN decomposed in the furnace chamber is gradually deposited on the surface of the carbon fiber to form a gradient coating. The coating of the product of the invention is uniform, dense and stable at high temperature, and can also greatly improve the oxidation resistance of the carbon fiber.

Description

technical field [0001] The invention belongs to the technical field of ceramic matrix composite materials and its preparation, and in particular relates to a carbon fiber with a deposited coating on its surface and a preparation method thereof. Background technique [0002] The bulk density of carbon fiber reinforced ceramic matrix composites is usually less than 2.0g / cm 3 , which is only 1 / 2 of ceramic materials and 1 / 4 of nickel-based superalloys, and has excellent mechanical properties such as high modulus, high specific strength, and low thermal expansion coefficient, especially at ultra-high temperatures (up to 2200 ° C), Its strength does not fall but rises, which is higher than that at normal temperature, so carbon fiber reinforced ceramic matrix composites are an excellent high-temperature structural material. However, the carbon fibers and interfacial phases in composite materials are easily oxidized at high temperature, which greatly limits their application under...

AI Technical Summary

Problems solved by technology

However, in the preparation of the above-mentioned SiBCN coatings, two or more types of deposition gas sources are used, the process is relatively complicated, and most of the deposition reaction process produces corrosive by-products, which have adverse effects on deposition substrate materials and equipment, and Not suitable for industrial production of SiBCN

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