Fiber-reinforced heat-resistant sound-absorbing material and process for producing the same
AssigneesIHI Corporation, Ube Industries, Ltd.
InventorsTsutomu Oishi, Yoshizumi Tanaka, Norifumi Miyamoto, Michiyuki Suzuki, Mitsuhiko Sato
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Abstract
A production process which comprises a preform formation step of forming a fiber preform made of silicon carbide short fibers having heat resistance of 1000° C. or greater; a sol-gel preparation step of preparing a sol-gel solution containing a heat resistant compound having heat resistance of 1000° C. or greater; an impregnation-drying-calcination step of impregnating the fiber preform with the sol-gel solution, followed by drying and calcining; and a crystallization step of crystallizing the fiber preform after impregnation, drying and calcination.
Claims3
A process for producing a fiber-reinforced heat-resistant sound-absorbing material, the process comprising the steps of:
- (a) forming a fiber preform made of silicon carbide short fibers having a length of 50 mm or less and a heat resistance of at least 1000° C.;
- (b) preparing a sol-gel solution containing a heat resistant compound having heat resistance of at least 1000° C.;
- (c) impregnating the fiber preform with the sol-gel solution, then drying and calcining the fiber preform;
- and
- (d) crystallizing the fiber preform after impregnation, drying and calcination,
- wherein the silicon carbide fibers contain a metal element which is selected form the class consisting of Group I, III and IV metal atoms of the periodic table and in which a temperature at which a free energy change in the carbon reduction reaction of the oxide of the metal element becomes a negative value is higher than a temperature at which a free energy change in the carbon reduction reaction of silicon oxide becomes a negative value;
- and wherein the silicon carbide fibers have an oxygen content falling within a range of from 2 to 13 wt. %,
- wherein the resulting fiber-reinforced heat-resistant sound-absorbing material has a porosity of at least 95%, and a noise absorption of at least 95 % in a frequency band of 1000 to 4000 Hz.
Dependencies are inferred from the claim text.