摘要:
A method of forming a composite article includes impregnating an inorganic fiber preform with a slurry composition. The slurry composition includes a particulate, a solvent, and a pre-gellant material. Gelling of the pre-gellant material in the slurry composition is initiated to immobilize the particulate and yield a gelled article, and substantially all solvent is removed from the gelled article to form a green composite article. The green composite article is then infiltrated with a molten infiltrant to form the composite article.
摘要:
Methods for forming a ceramic matrix composite (CMC) are generally provided. The method may include melt infiltrating a silicon mixture into a ceramic matrix composite preform, with the silicon mixture including SiGa, SiIn, or a mixture thereof. The silicon mixture may include silicon metal in combination with SiGa, SiIn, or the mixture thereof. Additionally, the silicon mixture may further include B within the SiGa, SiIn, or the mixture thereof (e.g., in the form of SiBGa, SiBIn, or a mixture thereof).
摘要:
This relates to a turbine blade comprising a preformed fibrous fabric of fibres consisting of carbon, silicon carbide or rhenium fixed with a binder resin, and wherein the preformed and fixed fibrous fabric is coated and infiltrated, respectively, with B4C, wherein the preformed fibrous fabric that has been fixed and coated and infiltrated, respectively, with B4C further has a multilayer coating consisting of at least one layer of silicon carbide and at least one layer of a metal boride, a metal nitride or a metal carbide, and wherein an oxide ceramic is applied over the multilayer coating. The turbine blade is resistant to high temperatures and is particularly well suited for use in a gas turbine. Methods for producing the turbine blade are also described.
摘要:
A chemically doped boron coating is applied by chemical vapor deposition to a silicon carbide fiber and the coated fiber then is exposed to magnesium vapor to convert the doped boron to doped magnesium diboride and a resultant superconductor.
摘要:
A porous substrate and method of forming a porous substrate including providing a fiber material, providing at least one extrusion aid, and providing at least one washcoat precursor. The fiber material, the at least one extrusion aid and the at least one washcoat precursor are mixed to provide an extrudable batch. The extrudable batch is extruded into a green substrate. The green substrate is fired to form a porous rigid substrate and to form a washcoat at least partially coating the fiber material.
摘要:
A fiber-reinforced silicon-silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon-silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.
摘要:
A composite comprised of reinforcement fibers having a continuous coating of a metal nitride wherein the metal is from the group consisting of silicon, aluminum, titanium, zirconium, hafnium, niobium, tantalum, and mixtures thereof, and a molten silicon infiltration formed silicon carbide matrix. The reinforcement fibers are fibers from the group consisting of elemental carbon, silicon carbide, and mixtures thereof. A method of forming the composite comprises depositing a continuous coating of the metal nitride on the fibers. A carbonaceous material is admixed with the coated fibers so that at least 5 volume percent of the mixture is the coated fibers. The mixture is formed into a preform having an open porosity ranging from about 25 volume percent to about 90 volume percent of the preform. The preform is heated in an inert atmosphere or partial vacuum, and infiltrated with molten silicon to produce an infiltrated product having the composition of the composite.
摘要:
A fiber-reinforced silicon--silicon carbide matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is produced. The invention also provides a method for protecting the reinforcing fibers in the silicon--silicon carbide matrix composites by coating the fibers with a silicon-doped boron nitride coating.
摘要:
A fiber reinforced ceramic matrix composite is disclosed which comprises a ceramic matrix and a fiber preform integrally assembled therein, the fiber preform comprising a braided fabric derivable from braiding a yarn which is composed of a plurality of fiber bundles formed of a plurality of monofilaments bundled together, the braided fabric being present in a volume fraction of fiber (Vf) of 10 to 40% by volume based on the total volume of the ceramic matrix composite. The yarns (fiber bundles) may preferably be disposed in oblique relation to each other. Initial matrix cracking strength, crack propagation resistance and fracture energy are greatly increased. Fiber preforms having a complicated shape can be easily obtained.
摘要:
The invention includes a process for producing a reaction bonded silicon carbide composite reinforced with coated silicon carbide fibers which is suitable for high temperature applications. The process includes the steps of coating SiC fibers with AlN, BN or TiB.sub.2 ; treating the coated fibers with a mixture of SiC powder, water and a surfactant; preparing a slurry comprising SiC powder and water; infiltrating the coated fibers with the slurry to form a cast; drying the cast to form a green body; and reaction bonding the green body to form a dense SiC fiber reinforced reaction bonded matrix composite.The invention further includes a SiC fiber reinforced SiC composite comprising a reaction bonded SiC matrix, a SiC fiber reinforcement possessing thermal stability at high temperatures and an interface coating on the fibers having chemical and mechanical compatibility with the SiC matrix and with the SiC fibers.