Patent Application
20180363476
The present invention is generally directed to a coated ceramic matrix composite component and a method of forming a coated ceramic matrix composite component. More specifically, the present invention is directed to a ceramic matrix composite component comprising a coated endface surface and a method of forming a ceramic matrix composite component comprising a coated endface surface.
Certain components such as ceramic matrix composite (CMC) components for a gas turbine operate at high temperatures and pressures. In particular, recession, off-gassing of silicon hydroxides in the presence of water vapor at high temperatures and pressures, can occur at temperatures above 1500° F. Purge flow may be formed to help cool the surface of components below the recession temperature. However, purge flow may lead to undesirable reduction in turbine aerodynamics and overall turbine efficiency.
In an exemplary embodiment, a coated ceramic matrix composite component for a gas turbine is provided. The coated ceramic matrix composite component comprises a substrate comprising an endface surface and a hot gas path surface. The hot gas path surface is arranged and disposed to contact a hot gas path when the component is installed in the gas turbine. The endface surface is disposed at an endface angle to the hot gas path surface and opposing at least one adjacent component when the component is installed in the gas turbine. The coated ceramic matrix composite component further comprises an environmental barrier coating on at least a portion of the endface surface.
In another exemplary embodiment, a gas turbine assembly comprising a plurality of a coated ceramic matrix composite component is provided. The coated ceramic matrix composite component comprises a substrate comprising an endface surface and a hot gas path surface. The hot gas path surface is arranged and disposed to contact a hot gas path. The endface surface is disposed at an endface angle to the hot gas path surface and opposing at least one adjacent component in the gas turbine assembly. The coated ceramic matrix composite component further comprises an environmental barrier coating on at least a portion of the endface surface.
In another exemplary embodiment, a method for forming a coated ceramic matrix composite component for a gas turbine is provided. The method comprises a step of providing a component comprising a substrate comprising an endface surface and a hot gas path surface. The method further comprises a step of forming an environmental barrier coating on at least a portion of the endface surface. The hot gas path surface is arranged and disposed to contact a hot gas path when the component is installed in the gas turbine, and the endface surface is disposed at an endface angle to the hot gas path surface and opposing at least one adjacent component when the component is installed in the gas turbine.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.
Wherever possible, the same reference numbers will be used throughout the drawings to represent the same parts.
Provided are exemplary methods and coated ceramic matrix composite components. Embodiments of the present disclosure, in comparison to methods and coated ceramic matrix composite components not utilizing one or more features disclosed herein, provide an environmental barrier coating to the endface surface of the components and prevent recession, thereby prolong the part life.
With reference to
With reference to
In one embodiment, substrate 101 comprises a ceramic matrix composite material selected from the group consisting of carbon-fiber-reinforced silicon carbide (C/SiC), silicon-carbide-fiber-reinforced silicon carbide (SiC/SiC), carbon-fiber-reinforced silicon nitride (C/Si3N4), silicon nitride-silicon carbide composite (Si3N4/SiC), alumina-fiber-reinforced alumina (Al2O3/Al2O3), and combinations thereof.
In one embodiment, environmental barrier coating 106 comprises a bond coat and a top coat. In another embodiment, environmental barrier coating 106 consists of a bond coat and a top coat. In another embodiment, environmental barrier coating 106 comprises a bond coat and multiple top coats. In another embodiment, environmental barrier coating 106 consists of a bond coat and multiple top coats. In another embodiment, environmental barrier coating 106 comprises multiple bond coats and a top coat. In another embodiment, environmental barrier coating 106 consists of multiple bond coats and a top coat. In another embodiment, environmental barrier coating 106 comprises multiple bond coats and multiple top coats. In another embodiment, environmental barrier coating 106 consists of multiple bond coats and multiple top coats. In another embodiment, environmental barrier coating 106 comprises at least one bond coat, at least one thermally grown oxide layer and at least one top coat. In another embodiment, environmental barrier coating 106 consists of at least one bond coat, at least one thermally grown oxide layer and at least one top coat.
In one embodiment, suitable bond coat comprises a material selected from the group consisting of silicon, silicon-based alloy, silicon-based composite, silicon dioxide, MCrAlY and combinations thereof; wherein M is Ni, Co, Fe, or mixtures thereof. A person skilled in the art will appreciate that any suitable bond coat materials are envisaged.
In one embodiment, environmental barrier coating 106 further comprises a transition layer comprising a material selected from the group consisting of barium strontium alumino silicate (BSAS), mullite, yttria-stabilized zirconia, (Yb,Y)2Si2O7, rare earth monosilicates and disilicates and combinations thereof. A person skilled in the art will appreciate that any suitable EBC materials are envisaged.
In one embodiment, suitable top coat comprises a material selected from the group consisting of Y2SiO5, barium strontium alumino silicate (BSAS), yttria-stabilized zirconia, yttria-stabilized hafnia, yttria-stabilized zirconia with additions of one or more rare earth oxides, yttria-stabilized hafnia with additions of one or more rare earth oxides and combinations thereof. A person skilled in the art will appreciate that any suitable top coat materials are envisaged.
In one embodiment, coated ceramic matrix composite component 100 is a turbine component. Coated ceramic matrix composite component 100 may be selected from the group consisting of shrouds, nozzles, blades, combustors, combustor transition pieces, combustor liners, combustor tiles and combinations thereof. In one embodiment, coated ceramic matrix composite component 100 is a shroud. A person skilled in the art will appreciate that any suitable coated ceramic matrix composite components are envisaged.
With reference to
With reference to
With reference to
In one embodiment, the step of forming the environmental barrier coating comprises at least one of physical vapor deposition, chemical vapor deposition, plasma-enhanced chemical vapor deposition, air plasma spray, vacuum plasma spray, combustion spraying with powder or rod, slurry coating, sol gel, dip coating, electrophoretic deposition and tape casting.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
