Polyaluminocarbosilane with high aluminum content and low oxygen content, preparation method and SiAlC ceramic

Abstract

The invention discloses a preparation method of polyaluminocarbosilane with high aluminum content and low oxygen content. Liquid hyperbranched liquid polycarbosilane and methylaluminoxane are adopted as raw materials, polyaluminocarbosilane is prepared under closed inert conditions, and the content of aluminum element in the polyaluminocarbosilane can be adjusted by adjusting the ratio of the raw materials. The invention also discloses the polyaluminocarbosilane prepared based on the method, the mass percentage content of aluminum element can be 0-20%, and the mass percentage content of oxygen element is less than 2%. The invention further discloses SiAlC ceramic obtained after high-temperature cracking of the polyaluminocarbosilane, Si, Al and C elements in the SiAlC ceramic are adjustable in composition, and the SiAlC ceramic has excellent high temperature resistance and oxidation resistance, can be used for preparing an ultrahigh-temperature-resistant C / SiAlC ceramic-based composite material through a PIP method, and can also be used for preparing an ultrahigh-temperature oxidation-resistant coating and fiber.

Description

Technical field [0001] Polyaluminocarbosilane present invention belongs to the technical field for preparing a precursor of silicon carbide, in particular to a low oxygen content in the high aluminum content, and a method for preparing a ceramic SiAlC. Background technique [0002] Polyaluminocarbosilane silicon carbide fibers as the third generation precursor, has been widespread concern by scholars, Tyranno SA fibers produced from the pyrolysis polyaluminocarbosilane fiber is the best known high-temperature properties, the aluminum preparation of silicon carbide ceramic precursor is of great significance. [0003] Currently, the preparation of aluminum-containing preceramic mainly by reaction of the organosilicon polymer and aluminum-containing compounds obtained. According to the state of the silicone polymer, synthetic aluminum-containing preceramic classification may be to use a solid synthetic organic polymer and silicon with liquid silicone polymer synthesis. Initially, Ja...

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Problems solved by technology

[0005] The object of the present invention is to overcome above-mentioned defect, provide a kind of preparation method of the polyaluminocarbosilane of high aluminum content, low oxygen content, this method adopts liquid hyperbranched liquid polycarbosilane and methyl aluminoxane as raw material, in airtight inert Under certain conditions, hyperbranched liquid polycarbosilane and aluminoxane compound are grafted and copolymerized to prepare polyaluminocarbosilane. By adjusting the ratio of raw materials, the content of aluminum in polyaluminocarbosilane can be adjusted, and the preparation process is simple. , no by-products are produced, and the problems of high preparation temperature and complicated reaction of polyaluminocarbosilane are avoided; the present invention also provides a polyaluminocarbosilane prepared based on the above method, which has high and adjustable aluminum content, low oxygen content, etc. Features, the mass percentage content of aluminum element can be 0-20%, and the mass percentage content of oxygen element is less than 2%. The element composition is adjustable, which can be used to prepare aluminum-containing SiC fibers, high-temperature coatings, fiber reinforcements, and ceramic matrix composite materials;

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