摘要:
Silicon carbide ceramic matrix composites, and hybrid ceramic materials are provided. In one embodiment, the silicon carbide composites comprise reinforcement material further comprising a simplified coating, and in others, the composites comprise uncoated reinforcement material. The hybrid ceramic materials comprise at least two of a conventional ceramic matrix composite, a monolithic ceramic, the composite comprising uncoated reinforcement material, and the composite comprising reinforcement material comprising a simplified coating. Methods of providing the composites are also provided.
摘要:
A treated refractory material includes a sintered porous refractory material having one or more protective materials disposed within pores of the refractory material, wherein the protective material is selected from the group consisting of aluminum oxide, chromium oxide, silica, rare earth oxides, rare earth zirconates, titanium oxide, mullite, zirconium oxide, zirconium silicate, yttrium oxide, magnesium oxide, iron oxide, and blends thereof. Methods of preparing the treated refractory material are also provided. The treated refractory material provides protection from the penetration of slag and extends the service life of the refractory.
摘要:
An article for use at high temperature, such as a component for a gas turbine assembly, is presented. The article comprises a substrate comprising silicon; a bondcoat disposed over the substrate, wherein the bondcoat comprises a silicide of a platinum-group metal; and a topcoat disposed over the bondcoat, wherein the topcoat comprises a ceramic material.
摘要:
A method of operating a gas turbine that utilizes vanadium-containing fuels at a combustion stage of the turbine thereby producing a combustion product having vanadium gaseous species, the method comprising increasing the volatility of the vanadium gaseous species in the combustion product atmosphere generated in a combustor of the turbine by increasing concentration of water vapor in the combustion product.
摘要:
A treated refractory material includes a sintered porous refractory material having one or more protective materials disposed within pores of the refractory material, wherein the protective material is selected from the group consisting of aluminum oxide, chromium oxide, silica, rare earth oxides, rare earth zirconates, titanium oxide, mullite, zirconium oxide, zirconium silicate, yttrium oxide, magnesium oxide, iron oxide, and blends thereof. Methods of preparing the treated refractory material are also provided. The treated refractory material provides protection from the penetration of slag and extends the service life of the refractory.
摘要:
A Silicon carbide-silicon matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is provided. A method is given for sealing matrix cracks in situ in melt infiltrated silicon carbide-silicon matrix composites. The composite cracks are sealed by the addition of various additives, such as boron compounds, into the melt infiltrated silicon carbide-silicon matrix.
摘要:
A barrier layer for a silicon containing substrate which inhibits the formation of gaseous species of silicon when exposed to a high temperature aqueous environment comprises a calcium alumino silicate.
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 Silicon carbide-silicon matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is provided. A method is given for sealing matrix cracks in situ in melt infiltrated silicon carbide-silicon matrix composites. The composite cracks are sealed by the addition of various additives, such as boron compounds, into the melt infiltrated silicon carbide-silicon matrix.
摘要:
A system comprises a plurality of components disposed to define a gas path. At least one component comprises a silicon-bearing substrate over which is disposed a coating, and the coating comprises a recession-resistant material exposed to the gas path. A silicon source is disposed in fluid communication with the gas path and is configured to be delivered to the gas path to maintain, in gas flowing in the gas path over the coating, a silicon mass concentration in the range from about 1.8×10−4 parts per million to about 1 part per million An associated method comprises directing a combustion gas flow within a gas path, the gas path defined by a plurality of components, wherein at least one component comprises a silicon-bearing substrate over which is disposed a coating, the coating comprising a recession-resistant material exposed to the gas path; and delivering a silicon-containing material to the gas flow from a silicon source disposed in fluid communication with the gas path to maintain within the gas flow over the coating, a silicon mass concentration in the range from about 1.8×10−4 parts per million to about 1 part per million.