Abstract: A composition useful as a thermal barrier coating on a superalloy substrate intended for use in hostile thermal environments. The coating comprises zirconia stabilized in a predominately tetragonal phase. The composition includes a ceramic component consisting essentially of zirconia (ZrO2) or a combination of zirconia and hafnia (HfO2) and a stabilizer component comprising, in combination, a first co-stabilizer selected from YbO1.5, HoO1.5, ErO1.5, TmO1.5, LuO1.5, and combinations thereof, and a second co-stabilizer selected from TiO2, PdO2, VO2, GeO2, and combinations thereof. Optionally, the stabilizer component includes Y2O3. The stabilizer component is present in an amount effective to achieve the predominantly tetragonal phase in the coating.

Abstract: A composition useful as a thermal barrier coating on a superalloy substrate intended for use in hostile thermal environments. The coating comprises zirconia stabilized in a predominately tetragonal phase. The composition includes a ceramic component consisting essentially of zirconia (ZrO2) or a combination of zirconia and hafnia (HfO2) and a stabilizer component comprising, in combination, a first co-stabilizer selected from YbO1.5, HoO1.5, ErO1.5, TmO1.5, LuO1.5, and combinations thereof, and optionally YO1.5, a second co-stabilizer selected from TiO2, PdO2, VO2, GeO2, and combinations thereof, and a third co-stabilizer comprising TaO2.5. The stabilizer component is present in an amount effective to achieve the predominantly tetragonal phase in the coating.

Abstract: A composition is disclosed that includes an at least partially stabilized zirconia matrix with a pentavalent oxide first dopant and an oxide second dopant. A coated article is disclosed for use in a high temperature a gas turbine. The coated article can include an yttria-stabilized zirconia, a pentavalent oxide first dopant, and an oxide second dopant. The ratio of the pentavalent oxide second dopant to the oxide third dopant can be less than or equal to about 1. The composition can reduce sintering of the thermal barrier coating.

Abstract: A method for applying a NiAl based bond coat and a diffusion aluminide coating to a metal substrate comprises, in part, coating a portion of the external surface of the superalloy substrate, by physical vapor deposition with a layer of a NiAl based metal alloy, wherein the deposited NiAl based metal alloy includes a controlled amount of about 6 to 25 weight percent aluminum, wherein the deposited aluminum level of the NiAl based metal alloy is controlled to be about 50-100% of its final level after aluminizing to form a coated external portion; and subsequently, simultaneously aluminizing the coated external portion and a different surface of the superalloy substrate.

Abstract: An intermetallic composition suitable for use as an environmentally-protective coating on surfaces of components used in hostile thermal environments, including the turbine, combustor and augmentor sections of a gas turbine engine. The coating contains the gamma-prime (Ni3Al) nickel aluminide intermetallic phase and either the beta (NiAl) nickel aluminide intermetallic phase or the gamma solid solution phase. The coating has an average aluminum content of 14 to 30 atomic percent and an average platinum-group metal content of at least 1 to less than 10 atomic percent, the balance of the coating being nickel, incidental impurities, and optionally hafnium.

Abstract: An intermetallic composition suitable for use as an environmentally-protective coating on surfaces of components used in hostile thermal environments, including the turbine, combustor and augmentor sections of a gas turbine engine. The coating contains the gamma-prime (Ni3Al) nickel aluminide intermetallic phase and either the beta (NiAl) nickel aluminide intermetallic phase or the gamma solid solution phase. The coating has an average aluminum content of 14 to 30 atomic percent and an average platinum-group metal content of at least 1 to less than 10 atomic percent, the balance of the coating being nickel, one or more of chromium, silicon, tantalum, and cobalt, optionally one or more of hafnium, yttrium, zirconium, lanthanum, and cerium, and incidental impurities.

Abstract: An article comprising a silicon-containing substrate, a silicide-containing bond coat layer overlying the substrate, and an environmental barrier coating (EBC) overlying the bond coat layer, wherein the EBC comprises a corrosion resistant outer layer comprising a corrosion resistant metal silicate. A process is also provided for forming the corrosion resistant outer layer over the silicide-containing bond coat layer.

Abstract: A thermal barrier coating and deposition process for a component intended for use in a hostile thermal environment, such as the turbine, combustor and augmentor components of a gas turbine engine. The TBC has a first coating portion on at least a first surface portion of the component. The first coating portion is formed of a ceramic material to have at least an inner region, at least an outer region overlying the inner region, and a columnar microstructure whereby the inner and outer regions comprise columns of the ceramic material. The columns of the inner region are more closely spaced than the columns of the outer region so that the inner region of the first coating portion is denser than the outer region of the first coating portion, wherein the higher density of the inner region promotes the impact resistance of the first coating portion.

Abstract: An article comprising a silicon-containing substrate, a silicide-containing bond coat layer overlying the substrate, and typically an environmental barrier coating overlaying the bond coat layer. An article is also provided wherein the environmental barrier coating comprises: (1) an optional inner silica scale layer overlaying the bond coat layer; (2) intermediate layer overlaying the inner silica scale layer, or the bond coat layer in the absence of the inner silica scale layer, and comprising mullite, or a combination of mullite with a barium strontium aluminosilicate, a yttrium silicate, or a calcium aluminosilicate; and (3) an outer steam-resistant barrier layer overlaying the intermediate layer and consisting essentially of an alkaline earth silicate/aluminosilicate. Processes are also provided for forming the silicide-containing bond coat layer over the substrate, followed by forming the environmental barrier coating over the bond coat layer.

Abstract: Zirconia-containing ceramic compositions that are capable of providing thermal barrier coatings wherein the zirconia is stabilized in the cubic crystalline phase. These compositions comprise at least about 50 mole % zirconia and a stabilizing amount up to about 49 mole % of a stabilizer component comprising: (1) a first metal oxide selected from the group consisting of ytterbia, neodymia, mixtures of ytterbia and neodymia, mixtures of ytterbia and lanthana, mixtures of neodymia and lanthana, and mixtures of ytterbia, neodymia and lanthana in an amount of from about 5 to about 49 mole % of the composition; and (2) a second metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof in an amount of about 4 mole % or less of the composition. The ceramic composition further comprises one or more of a third metal oxide selected from the group consisting of: (a) hafnia in an amount from about 0.

Abstract: A thermal barrier coating for an underlying metal substrate of articles that operate at, or are exposed to, high temperatures, as well as being exposed to environmental contaminant compositions. This coating comprises an optional inner layer nearest to the underlying metal substrate comprising a non-alumina ceramic thermal barrier coating material in an amount up to 100%, and an outer layer having an exposed surface and comprising at least about 50% of a non-alumina ceramic thermal barrier coating material and alumina in an amount up to about 50% and sufficient to protect the thermal barrier coating at least partially against environmental contaminants that become deposited on the exposed surface. This coating can be used to provide a thermally protected article having a metal substrate and optionally a bond coat layer adjacent to and overlaying the metal substrate.

Abstract: In accordance with an embodiment of the invention, an article is provided. The article comprises a substrate comprised of silicon containing material, an environmental barrier coating (EBC) overlying the substrate and a thermal barrier coating (TBC) on the environmental barrier coating. The thermal barrier coating comprising a compound having a rhombohedral phase.

Abstract: In accordance with an embodiment of the invention, a thermal barrier coating (TBC) for inclusion in a thermal barrier coating/environmental barrier coating system (TBC/EBC system) for use on a silicon containing material substrate is provided. The TBC comprises a compound having a primary constituent portion and a stabilizer portion stabilizing said primary constituent. The primary constituent portion of the TBC comprises hafnia present in an amount of at least about 5 mol % of the primary constituent. The stabilizer portion of said thermal barrier coating comprises at least one metal oxide comprised of cations with a +2 or +3 valence present in the amount of about 10 to about 40 mol % of the thermal barrier coating.

Abstract: Methods for depositing an overlay coating on articles intended for use in hostile thermal environments. The coating has a predominantly gamma prime-phase nickel aluminide (Ni3Al) composition suitable for use as an environmental coating and as a bond coat of a thermal barrier coating system. The coating further contains at least one platinum group metal, preferably chromium, optionally one or more reactive elements, and optionally silicon. The coating is deposited by a process that entails forming a platinum group metal layer and at least one separate layer of other constituents of the coating, and then performing a diffusion heat treatment to yield the coating.

Abstract: Thermal barrier coating (TBC) and a method of depositing a TBC having a modulated columnar microstructure that exhibits increased impact resistance. The TBC is deposited to have a columnar microstructure in which columns extend from a substrate surface. The columns having inner regions contacting the surface, outer regions near an outermost surface of the TBC, and interior regions therebetween. The inner regions of the columns are substantially normal to the substrate surface and at least one of the interior and outer regions of the columns are nonaligned with its respective inner regions, so that the columns of the columnar microstructure are continuous but modulated between the inner and outer regions to reduce tensile stresses within the columns resulting from particle impact.

Abstract: A composition is disclosed that includes an at least partially stabilized zirconia matrix with a pentavalent oxide first dopant and an oxide second dopant. A coated article is disclosed for use in a high temperature a gas turbine. The coated article can include an yttria-stabilized zirconia, a pentavalent oxide first dopant, and an oxide second dopant. The ratio of the pentavalent oxide second dopant to the oxide third dopant can be less than or equal to about 1. The composition can reduce sintering of the thermal barrier coating.

Abstract: Zirconia-containing ceramic compositions useful for thermal barrier coatings having improved mechanical properties, especially improved fracture toughness. These compositions comprise: (1) at least about 93 mole % zirconia; (2) a stabilizing amount up to about 5 mole % of a stabilizer metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india, gadolinia, neodymia, samaria, dysprosia, erbia, ytterbia, europia, praseodymia, and mixtures thereof, and a fracture toughness improving amount up to about 2 mole % lanthana. These ceramic compositions can be used to prepare thermal barrier coatings to provide a thermally protected article having a substrate and optionally a bond coat layer adjacent to and overlaying the substrate. The thermal barrier coating can be prepared by depositing the ceramic composition on the bond coat layer or the substrate in the absence of a bond coat layer.

Abstract: A reduced thermal conductivity thermal barrier coating having improved impact resistance for an underlying substrate of articles that operate at, or are exposed to, high temperatures. This coating comprises an inner high fracture toughness layer nearest to the underlying substrate and having a thickness up to about 5 mils (127 microns) sufficient to impart impact resistance to the thermal barrier coating, and comprises a zirconia-containing ceramic composition having a c/a ratio of the zirconia lattice in the range of from about 1.011 to about 1.016 and stabilized in the tetragonal phase by a stabilizing amount of a stabilizing metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india, lanthana, gadolinia, neodymia, samaria, dysprosia, erbia, ytterbia, europia, praseodymia, and mixtures thereof.

Abstract: Ceramic compositions comprising a main ceramic component comprising from about 63 to about 99 mole % zirconia and from about 1 to about 37 mole % hafnia. These compositions further comprise at least about 4 mole % of a stabilizer metal oxide selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india, lanthana, gadolinia, neodymia, samaria, dysprosia, erbia, ytterbia, europia, praseodymia, and mixtures thereof. These ceramic compositions are useful in preparing thermal barrier coatings having reduced thermal conductivity for the substrate of articles that operate at, or are exposed to, high temperatures, as well as good producibility and impact/erosion resistance. Inclusion of hafnia also maintains the reduced conductivity of the thermal barrier coating after thermal exposure due to better sintering resistance.

Abstract: Ceramic compositions comprising at least about 91 mole % zirconia and up to about 9 mole % of a stabilizer component comprising a first metal oxide having selected from the group consisting of yttria, calcia, ceria, scandia, magnesia, india and mixtures thereof. This stabilizer component further comprises a second metal oxide of a trivalent metal atom selected from the group consisting of lanthana, gadolinia, neodymia, samaria, dysprosium, and mixtures thereof and a third metal oxide of a trivalent metal atom selected from the group consisting of erbia, ytterbia and mixtures thereof. These ceramic compositions are useful in preparing thermal barrier coatings having reduced thermal conductivity for the metal substrate of articles that operate at, or are exposed to, high temperatures.