PROCESS FOR PRODUCING CERAMIC PRODUCT

摘要

A ceramic product is produced by mixing a preform of metallic or ceramic fibers or a porous ceramic with at least one polysilazane (1) having a number-average molecular weight of 20 to 3,000 and a cold viscosity of less than 1 Pa.s and selected from among a polysilazane mainly comprising repeating units of the formula -[(SiH2)n(NH)r]- (wherein n and r are each 1, 2 or 3) and derivatives based thereon, such as copolymers, modified polymers and cross-linked polymers, and at least one polysilazane (2) selected from among ones having a number-average molecular weight of 200 to 100,000 and a cold viscosity of 100 Pa.s or above and solid ones, impregnating the mixture with a polysilazane-base polymer mixture having a number-average molecular weight of 200 to 3,000 and a cold viscosity of 100 Pa.s or less, hardening the resulting mixture by cross-linking, firing the same into a ceramic, and repeating these operations. Examples of the polysilazanes include inorganic polysilazane, inorganic polysiloxazane, polyorgano(hydro)silazane, modified polysilazane and polymetallosilazane. It is possible to inhibit the delamination of the fibers by applying CVD coating before or after the impregnation, hardening and firing of the preform.