Abstract:
The present application provides methods and apparatus for processing ceramic fibers for the manufacture of ceramic matrix composites (CMCs). One method may include providing at least one frame including a planar array of unidirectional ceramic fibers extending across a void thereof. The method may further include depositing a coating on the ceramic fibers of the at least one frame via a chemical vapor deposition (CVD) process. The method may also include impregnating the coated ceramic fibers with a slurry including a ceramic matrix precursor composition to form at least one CMC prepreg, such as a prepreg tape. The ceramic fibers may be substantially SiC fibers, for example.
Abstract:
A method for fabricating thermal barrier coatings. The thermal barrier coatings are produced with a fine grain size by reverse co-precipitation of fine powders. The powders are then sprayed by a solution plasma spray that partially melts the fine powders while producing a fine grain size with dense vertical cracking. The coatings comprise at least one of 45%-65% Yb2O3 the balance zirconia (zirconium oxide), Yb/Y/Hf/Ta the balance zirconia (zirconium oxide) and 2.3-7.8% La, 1.4-5.1% Y and the balance zirconia (zirconium oxide) and are characterized by a thermal conductivity that is about 25-50% lower than that of thermal barrier coatings comprising YSZ. The thermal barrier coatings also are characterized by at least one of excellent erosion resistance, fracture toughness and abrasion resistance.
Abstract:
A system and method described herein relate to applying an overlay metal-based coating to a metal-based substrate. An article is provided, which includes a metal-based substrate having an overlay metal-based coating disposed on the substrate at an interface. The interface is configured such that a crack formed within the overlay metal-based coating and approaching the interface has a propagation path that is more energetically favorable along the interface than through the interface and into the metal-based substrate.
Abstract:
Coatings for substrates, such as superalloy substrates, are provided. The coating can include: 15 wt % to 45 wt % cobalt; 20 wt % to 40 wt % chromium; 2 wt % to 15 wt % aluminum; 0.1 wt % to 1 wt % yttrium; and nickel. The coatings may include nickel, cobalt, chromium and aluminum, and other optional additives to improve oxidation and corrosion resistance of the substrate without significant debit to its mechanical properties.
Abstract:
The present application provides methods and apparatus for processing ceramic fibers for the manufacture of ceramic matrix composites (CMCs). One method may include providing at least one frame including a planar array of unidirectional ceramic fibers extending across a void thereof. The method may further include depositing a coating on the ceramic fibers of the at least one frame via a chemical vapor deposition (CVD) process. The method may also include impregnating the coated ceramic fibers with a slurry including a ceramic matrix precursor composition to form at least one CMC prepreg, such as a prepreg tape. The ceramic fibers may be substantially SiC fibers, for example.
Abstract:
An article includes a substrate comprising a precipitate-strengthened alloy and a coating disposed over the substrate. The alloy comprises a) a population of gamma-prime precipitates, the population having a multimodal size distribution with at least one mode corresponding to a size of less than about 100 nanometers; or b) a population of gamma-double-prime precipitates having a median size less than about 300 nanometers. The coating comprises at least two elements, and further comprises a plurality of prior particles. At least a portion of the coating is substantially free of rapid solidification artifacts. Methods for fabricating the article and for processing powder useful for fabricating the article are also provided.
Abstract:
A method for manufacturing a fuel contacting component that facilitates reducing coke formation on at least one surface of the fuel contacting component is disclosed herein. The method includes applying a slurry composition including a powder including aluminum to the component surface, wherein the fuel contacting component is formed by an additive manufacturing process. The slurry composition is heat treated to diffuse the aluminum into the component surface. The heat treatment comprises forming a diffusion aluminide coating on the component surface, wherein the diffusion coating comprises a diffusion sublayer formed on the component surface and an additive sublayer formed on the diffusion sublayer. The method further comprises removing the additive sublayer of the diffusion aluminide coating with at least one aqueous solution such that the diffusion sublayer and the component surface are substantially unaffected, wherein the diffusion layer facilitates preventing coke formation on component surface.
Abstract:
A method for coating a surface of a substrate is provided. The method includes providing a suspension or a precursor comprising feedstock material suspended in a liquid medium. Further, the method includes spraying the suspension or the precursor onto the surface at a spray angle less than about 75 degrees to a tangent of the surface.
Abstract:
One aspect of the present invention includes an article. The article includes a substrate and a coating disposed on the substrate, wherein the coating includes a plurality of cermet particles bonded along their prior particle boundaries. The plurality of cermet particles have a median particle size less than about 5 microns and less than 25 percent of the plurality of cermet particles include melted and re-solidified particles. Gate valves are also presented.
Abstract:
Coatings and articles suitable for use in high temperature environments, for example, are presented. One embodiment is a coating that comprises a plurality of elongate material growth domains defined between domain boundaries. The domains have an intra-domain density of at least about 75% of theoretical density, have a substantially equiaxed grain morphology, and comprise a plurality of at least partially melted and solidified particles. Another embodiment is a coating that comprises a matrix comprising a substantially equiaxed grain morphology and a plurality of vertically oriented cracks disposed in the matrix. Further embodiments include articles comprising one or more of the coatings described above.