Abstract: A composition is generally provided that includes a silicon-containing material (e.g., silicon metal and/or a silicide) and a boron-doped refractory compound, such as about 0.001% to about 85% by volume of the boron-doped refractory compound (e.g., about 1% to about 60% by volume). In one embodiment, a bond coating on a surface of a ceramic component is generally provided with the bond coating including such a composition, with the silicon-containing material is silicon metal.

Abstract: A ceramic component is provided that includes a silicon-based layer comprising a silicon-containing material (e.g., a silicon metal and/or a silicide) and a boron-doped refractory compound, such as about 0.001% to about 85% by volume of the boron-doped refractory compound (e.g., about 1% to about 60% by volume of the boron-doped refractory compound). A coated component is also provided that includes a CMC component defining a surface; a bond coating directly on the surface of the CMC component, with the bond coating comprises a silicon-containing material and a boron-doped refractory compound (e.g., about 0.1% to about 25% of the boron-doped refractory compound); a thermally grown oxide layer on the bond coating; and an environmental barrier coating on the thermally grown oxide layer.

Abstract: An article for high temperature service is presented herein. One embodiment is an article including a substrate having a silicon-bearing ceramic matrix composite; and a layer disposed over the substrate, wherein the layer includes silicon and a dopant, the dopant including aluminum. In another embodiment, the article includes a ceramic matrix composite substrate, wherein the composite includes a silicon-bearing ceramic and a dopant, the dopant including aluminum; a bond coat disposed over the substrate, where the bond coat includes elemental silicon, a silicon alloy, a silicide, or combinations including any of the aforementioned; and a coating disposed over the bond coat, the coating including a silicate (such as an aluminosilicate or rare earth silicate), yttria-stabilized zirconia, or a combination including any of the aforementioned.

Abstract: A method for removing a coating from an article includes heating an article to a processing temperature. The article includes a first material in contact with a second material, the first material comprising silicon, and the second material comprising an oxide comprising silicon. The heating is performed in an environment having a partial pressure of oxygen that is less than an equilibrium partial pressure of oxygen for chemical equilibrium between the first material and the second material at the processing temperature.

Abstract: The disclosure provides for an article including a substrate, an environmental barrier coating (EBC), a bondcoat and a boron source. The substrate may include a silicon-including ceramic material. The EBC may be disposed over the substrate, and the bondcoat may disposed between the substrate and the EBC. The bondcoat may include silicon. The boron source may be disposed within the article to provide an effective amount of boron to form an oxide including silicon and at least 0.1 weight percent boron during exposure of the bondcoat to an oxidizing environment at a temperature greater than 900 degrees Celsius. The oxide may be a borosilicate glass that is substantially devitrification resistant to prevent spallation of the EBC and thereby enhance the temperature capability of the article.

Abstract: An article includes a silicon-containing region; at least one outer layer overlying a surface of the silicon-containing region; and a constituent layer on the surface of the silicon-containing region and between and contacting the silicon-containing region and the at least one outer layer, the constituent layer being formed by constituents of the silicon-containing region and being susceptible to creep within an operating environment of the article, wherein the silicon-containing region defines a plurality of channels and a plurality of ridges that interlock within the plurality of channels are formed in the silicon-containing region to physically interlock the at least one outer layer with the silicon-containing region through the constituent layer.

Abstract: An article includes a silicon-containing region including surface features on a surface thereof. The surface features include depressions, protuberances, or combinations thereof. At least one outer layer overlies the surface of the silicon-containing region. A constituent layer is provided on the surface of the silicon-containing region and between and contacting the silicon-containing region and the at least one outer layer. The constituent layer is formed by constituents of the silicon-containing region and is susceptible to creep within an operating environment of the article. The surface features physically interlock the at least one outer layer with the silicon-containing region through the constituent layer.

Abstract: An article includes a substrate, a substantially hermetic sealing layer disposed on the substrate, and a porous transition layer disposed on the substrate between the sealing layer and the substrate. The article also includes one or more openings extending through the substrate to the porous transition layer.

Abstract: High-temperature machine components, more particularly, articles capable of operating in high-temperature environments, including for example turbines of gas engines, may be formed of a high temperature ceramic matrix composite that includes a ceramic substrate including silicon; an environmental harrier coating system including a silicon containing bond coat; and a diffusion barrier layer of a carbide or a nitride between the substrate of the article and the silicon bond coat of the environmental barrier coating system. The diffusion harrier layer selectively prevents or reduces the diffusion of boron and impurities from the substrate to the bond coat of the environmental barrier coating system.

Abstract: An article includes a silicon-containing region; at least one outer layer overlying a surface of the silicon-containing region; and a constituent layer on the surface of the silicon-containing region and between and contacting the silicon-containing region and the at least one outer layer, the constituent layer being formed by constituents of the silicon-containing region and being susceptible to creep within an operating environment of the article, wherein the silicon-containing region defines a plurality of channels and a plurality of ridges that interlock within the plurality of channels are formed in the silicon-containing region to physically interlock the at least one outer layer with the silicon-containing region through the constituent layer.

Abstract: A method of forming an article includes forming a silicon-containing layer on a silicon-containing region of a surface of a substrate of the article; forming a plurality of channels and ridges in the silicon-containing layer; and forming at least one outer layer overlying the surface of the silicon-containing region. The plurality of channels and ridges may be formed by adding silicon-containing material to the silicon-containing layer. The channels and ridges may be formed by subtracting material from the silicon-containing layer. The channels and ridges may be formed by forming channels or grooves in the silicon-containing region of the surface of the substrate prior to formation of the silicon-containing layer.

Abstract: An article includes a substrate and a coating provided on a surface of the substrate. The coating includes at least one metal silicide layer consisting essentially of MoSi2 or WSi2 or (Mo, W)Si2 or a platinum group metal silicide and at least one layer consisting essentially of Si3N4.

Abstract: An article includes a silicon-containing region including surface features on a surface thereof. The surface features include depressions, protuberances, or combinations thereof. At least one outer layer overlies the surface of the silicon-containing region. A constituent layer is provided on the surface of the silicon-containing region and between and contacting the silicon-containing region and the at least one outer layer. The constituent layer is formed by constituents of the silicon-containing region and is susceptible to creep within an operating environment of the article. The surface features physically interlock the at least one outer layer with the silicon-containing region through the constituent layer.

Abstract: The disclosed embodiments include embodiments such as an X-ray tube cathode filament system. The X-ray tube cathode filament system includes a substrate and a coating disposed on the substrate. In this cathode filament system, an electron beam is emitted from the coating but not from the substrate. The electron beam is produced through the use of the thermionic effect.

Abstract: The disclosed embodiments include embodiments such as an X-ray tube cathode filament system. The X-ray tube cathode filament system includes a substrate and a coating disposed on the substrate. In this cathode filament system, an electron beam is emitted from the coating but not from the substrate. The electron beam is produced through the use of the thermionic effect.

Abstract: There are provided in accordance with embodiments of the invention metal-containing inorganic block copolymers, structures formed by self-assembly of such copolymers, and metal-containing ceramics which may be formed from such copolymers and/or structure. Methods for making such copolymers, structures and ceramics are also provided. Other embodiments are also disclosed.

Abstract: A method of forming a nanoscale ceramic composite generally includes modifying a polymeric ceramic precursor, mixing the modified polymeric ceramic precursor with a block copolymer to form a mixture, forming an ordered structure from the mixture, wherein the modified polymeric ceramic precursor selectively associates with a specific type of block of the block copolymer, and heating the ordered structure for a time and at a temperature effective to form the nanoscale ceramic composite.

Abstract: There are provided in accordance with embodiments of the invention metal-containing inorganic block copolymers, structures formed by self-assembly of such copolymers, and metal-containing ceramics which may be formed from such copolymers and/or structure. Methods for making such copolymers, structures and ceramics are also provided. Other embodiments are also disclosed.

Abstract: The present invention is generally directed to methods of making ceramics with nanoscale/microscale structure involving self-assembly of precursor materials such as, but not limited to, inorganic-based block co-polymers, inorganic-/organic-based hybrid block co-polymers, and other similar materials, and to the structures made by such methods. Where such precursor materials are themselves novel, the present invention is also generally directed to those materials and their synthesis.

Abstract: Thermoelectric materials, devices, and systems are presented. One embodiment is a composite material comprising a matrix comprising a thermoelectric material; and an electrically conducting phase disposed within the matrix. The electrically conducting phase has a lower electrical resistivity than the thermoelectric material, and it forms a continuous electrically conducting path through the matrix from a first surface of the material to a second surface of the material. Another embodiment is a device, comprising a thermoelectric element. This element is made of the above composite material. A further embodiment is a thermoelectric system, made of a heat source, a heat sink, and the thermoelectric device disposed in thermal communication with the heat source and heat sink. The system may be configured for power generation or for thermal management.