Abstract: A method of operating an EBPVD apparatus (10) to deposit a ceramic coating on an article (20), such that the thermal conductivity of the coating is both minimized and stabilized. More particularly, the EBPVD apparatus (10) is operated to perform multiple successive coating operations which together constitute a coating campaign. During the campaign, the surface temperatures of the articles (20) being coated do not exceed about 1000° C. as a result of the combined heat transfer from the coating chamber (14) to the articles (20) being reduced during the course of the campaign, even though the temperature within the coating chamber (14) continuously rises during successive coating operations of the campaign. Ceramic coatings deposited at such relatively low temperatures exhibit lower and more stable thermal conductivities.

Abstract: A gas turbine component article has an airfoil section and is formed of a nickel-base superalloy. An unmasked region of the airfoil section has a platinum aluminide protective coating, and a masked region of the airfoil section has an aluminide coating. The platinum aluminide preferably is deposited at a trailing edge of the airfoil section that is susceptible to low-cycle fatigue damage when a platinum aluminide coating is present.

Abstract: A method of operating an EBPVD apparatus (10) to deposit a ceramic coating on an article (20), such that the thermal conductivity of the coating is both minimized and stabilized. More particularly, the EBPVD apparatus (10) is operated to perform multiple successive coating operations which together constitute a coating campaign. During the campaign, the surface temperatures of the articles (20) being coated do not exceed about 1000° C. as a result of the combined heat transfer from the coating chamber (14) to the articles (20) being reduced during the course of the campaign, even though the temperature within the coating chamber (14) continuously rises during successive coating operations of the campaign. Ceramic coatings deposited at such relatively low temperatures exhibit lower and more stable thermal conductivities.

Abstract: A gas turbine component article has an airfoil section and is formed of a nickel-base superalloy. An unmasked region of the airfoil section has a platinum aluminide protective coating, and a masked region of the airfoil section has an aluminide coating. The platinum aluminide preferably is deposited at a trailing edge of the airfoil section that is susceptible to low-cycle fatigue damage when a platinum aluminide coating is present.

Abstract: A method for producing a thermal barrier coating system on an article that will be subjected to a hostile environment. The thermal barrier coating system is composed of a metallic bond coat and a ceramic thermal barrier coating having a columnar grain structure. The method generally entails forming the bond coat on the surface of a component, and then grit blasting the bond coat with an abrasive media having a particle size of greater than 80 mesh. The component is then supported within a coating chamber containing at least two ingots of the desired ceramic material. An absolute pressure of greater than 0.014 mbar is established within the chamber containing oxygen and an inert gas. Thereafter, the ceramic ingots are vaporized with an electron beam such that the vapor deposits on the surface of the component to form a layer of the ceramic material on the surface.

Abstract: A gas turbine component article has an airfoil section and is formed of a nickel-base superalloy. An unmasked region of the airfoil section has a platinum aluminide protective coating, and a masked region of the airfoil section has an aluminide coating. The platinum aluminide preferably is deposited at a trailing edge of the airfoil section that is susceptible to low-cycle fatigue damage when a platinum aluminide coating is present.

Abstract: A method of depositing a ceramic thermal barrier coating on an article that will be subjected to a hostile environment, such as turbine, combustor and augmentor components of a gas turbine engine. The thermal barrier coating is deposited by electron beam physical vapor deposition (EBPVD) using process parameters that include an absolute pressure of greater than 0.010 mbar and an oxygen partial pressure of greater than 50%, preferably at or close to 100%. Under these conditions, the desired ceramic material is evaporated with an electron beam to produce a vapor that deposits on the component to form a thermal barrier coating of the ceramic material.

Abstract: A curved component such as a turbine airfoil, shroud, or combustor centerbody is prepared with a platinum or a platinum-aluminide protective coating over only a portion of the surface thereof. The coating may serve as an environmental coating, or as a bond coat of a thermal barrier coating system. The partial coverage is achieved by depositing platinum only over a portion of the surface of the component, typically including the concave portion in the case of an airfoil, optionally depositing an aluminum layer, and optionally interdiffusing the platinum and aluminum layers.

Abstract: A component for use in a high-temperature environment such as the coating chamber of a PVD apparatus. A reflective coating on the component serves as a barrier to radiant heat transfer to the component by reflecting thermal radiation. The coating comprises at least one pair of reflective layers, each layer being formed of a material that is essentially transparent to electromagnetic wavelengths of between 500 and 3000 nanometers (nm). In addition, the material of the outermost layer of the pair has a higher index of refraction than the material of the other layer of the pair.

Abstract: A method of forming a thermal barrier coating on an article designed for use in a hostile thermal environment, such as turbine, combustor and augmentor components of a gas turbine engine. The method is particularly directed to increasing spallation resistance of thermal barrier coatings composed of an aluminum-containing bond coat formed on the surface of an article, and an insulating ceramic layer overlaying the bond coat. Processing steps include forming the bond coat on the surface of the article, and then treating the surface of the bond coat with laser energy so as to form a diffusion barrier layer of alumina. Thereafter, a ceramic material is deposited on the surface of the diffusion barrier layer so as to form the insulating ceramic layer. A preferred technique for the treating step is to scan the surface of the bond coat with an ultraviolet laser beam characterized by an appropriate beam geometry and fluence to yield the desired diffusion barrier layer.

Abstract: A thermal barrier coating adapted to be formed on an article subjected to a hostile thermal environment while subjected to erosion by particles and debris, as is the case with turbine, combustor and augmentor components of a gas turbine engine. The thermal barrier coating is composed of a metallic bond layer deposited on the surface of the article, a ceramic layer overlaying the bond layer, and an erosion-resistant composition dispersed within or overlaying the ceramic layer. The bond layer serves to tenaciously adhere the thermal insulating ceramic layer to the article, while the erosion-resistant composition renders the ceramic layer more resistant to erosion. The erosion-resistant composition is either alumina (Al.sub.2 O.sub.3) or silicon carbide (SiC), while a preferred ceramic layer is yttria-stabilized zirconia (YSZ) deposited by a physical vapor deposition technique to have a columnar grain structure.

Abstract: Evaporated ceramic coatings are prepared by furnishing an ingot of a ceramic material, treating the ingot to reduce sources of gas within the ingot, and evaporating the ceramic material in the ingot by melting the surface of the ingot with an intense heat source. The evaporated ceramic is deposited upon a substrate as the ceramic coating. The reduced gas content of the ingot decreases the incidence of spitting and eruptions from the molten surface of the ingot, thereby improving the quality of the deposited coating, and facilitating increases in evaporation rates and coatings process production rates.

Abstract: An article is protected by a thermal barrier coating system. The article includes a substrate having an outer surface and a thermal barrier coating system deposited upon the substrate. The thermal barrier coating system includes a porous region wherein the ceramic is present as a porosity-containing columnar grain structure extending substantially perpendicular to the substrate surface, and an erosion-resistant densified region overlying the porous region. The thermal barrier coating is preferably applied by rotating the substrate past a deposition source to deposit the columnar grains, and then halting or slowing the rotation while continuing the deposition of the erosion-resistant region.

Abstract: An aluminide coating is applied to a portion of the surface of an article that already has a thermal barrier coating system in place over another portion of its surface. The portion of the surface to be coated is contacted, at elevated temperature, with an aluminide coating source material that is a mixture of from about 18 to about 45 weight percent of a metallic source of aluminum and the balance ceramic particles. The metallic source of aluminum may be pure aluminum or an aluminum-containing alloy. No halide activator is present in the aluminide coating source material.