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: 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: A thermal barrier coating (TBC) for a component intended for use in a hostile thermal environment. The TBC has an interior region and an outer surface region on and contacting the interior region. Both regions are formed of a ceramic material, with the interior region having a lower thermal conductivity than zirconia partially stabilized by about seven weight percent yttria. The interior region constitutes more than half of the thickness of the TBC, and the outer surface region constitutes less than half of the thickness of the TBC. The TBC has a columnar microstructure whereby the interior region and the outer surface region comprise columns of their ceramic materials. The outer surface region is more erosion and impact resistant than the interior region at least in part as a result of the columns thereof being more closely spaced than the columns of the interior region.

Abstract: A beta-phase NiAl overlay coating containing a dispersion of ceramic particles and a process for depositing the overlay coating. If the coating is used to adhere a thermal barrier coating (TBC), the TBC exhibits improved spallation resistance as a result of the dispersion of ceramic particles having a dispersion-strengthening effect on the overlay coating. The overlay coating contains at least one reactive element and is deposited so that the some of the reactive element deposits as the ceramic particles dispersed in the overlay coating.

Abstract: A beta-phase NiAl overlay coating containing a dispersion of ceramic particles and a process for depositing the overlay coating. If the coating is used to adhere a thermal barrier coating (TBC), the TBC exhibits improved spallation resistance as a result of the dispersion of ceramic particles having a dispersion-strengthening effect on the overlay coating. The overlay coating contains at least one reactive element and is deposited so that the some of the reactive element deposits as the ceramic particles dispersed in the overlay coating.