초록 ▼

A near-net, complex shaped ceramic fiber reinforced silicon carbide based composite bodies with graded compositions and stress zones is disclosed. To provide the composite a fiber preform is first fabricated and an interphase is applied by chemical vapor infiltration, sol-gel or polymer processes. T

A near-net, complex shaped ceramic fiber reinforced silicon carbide based composite bodies with graded compositions and stress zones is disclosed. To provide the composite a fiber preform is first fabricated and an interphase is applied by chemical vapor infiltration, sol-gel or polymer processes. This first body is further infiltrated with a polymer mixture containing carbon, and/or silicon carbide, and additional oxide, carbide, or nitride phases forming a second body. One side of the second body is spray coated or infiltrated with slurries containing high thermal expansion and oxidation resistant, crack sealant phases and the other side of this second body is coated with low expansion phase materials to form a third body. This third body consisting of porous carbonaceous matrix surrounding the previously applied interphase materials, is then infiltrated with molten silicon or molten silicon-refractory metal alloys to form a fourth body. The resulting fourth body comprises dense composites consisting of fibers with the desired interphase which are surrounded by silicon carbide and other second phases materials at the outer and inner surfaces comprising material of silicon, germanium, refractory metal suicides, borides, carbides, oxides, and combinations thereof. The resulting composite fourth body has different compositional patterns from one side to the other.

대표청구항 ▼

[ What we claim is:] [1.] A method of forming a ceramic composite comprising the steps of:(a) providing a refractory fiber preform;(b) infiltrating the fiber preform with a mixture selected from polymer/resin mixture;(c) curing the infiltrated fiber preform at a temperature from about 60.degree. C.

[ What we claim is:] [1.] A method of forming a ceramic composite comprising the steps of:(a) providing a refractory fiber preform;(b) infiltrating the fiber preform with a mixture selected from polymer/resin mixture;(c) curing the infiltrated fiber preform at a temperature from about 60.degree. C. to about 90.degree. C.;(d) heating the cured, infiltrated fiber preform at about 600.degree. to about 700.degree. C. in an inert environment so as to convert said selected mixture to carbon;(e) defining first and second sides of said heated, cured, infiltrated fiber preform as being hot and cold operated sides respectively under operating conditions;(f) treating only said hot operated side with a liquid selected from paint or slurry each containing germanium powder and a fugitive binder;(g) treating only said cold operated side with a boron powder containing paint or slurry; and(h) infiltrating the fiber preform having the treated hot and cold operated sides with a molten material selected from the group consisting of molten silicon and molten binary silicon-refractory metal alloys.