摘要:
A nickel-base superalloy substrate has an overlying protective coating including a modified aluminum-containing protective layer. The modified aluminum-containing protective layer is formed of nickel, aluminum, calcium in an amount of from about 50 to about 300 parts per million by weight, and, optionally, elements interdiffused into the modified aluminum-containing protective layer from the substrate. Magnesium or barium may be used instead of or in addition to the calcium. A ceramic layer may overlie the modified aluminum-containing protective layer.
摘要:
A method and apparatus for forming a multilayer thermal barrier coating such that the coating is composed of substantially homogeneous layers of different ceramic materials. The method entails supporting an article within a coating apparatus and in proximity to ceramic ingots of the different ceramic materials, and then simultaneously directing electron beams at both ingots so as to maintain a portion of each ingot in a molten state. According to a particular aspect of this invention, vapors of both ceramic materials coexist within the coating apparatus, yet each ceramic material is sequentially deposited onto the article by sequentially interrupting exposure of surfaces of the article to the vapors, such that the vapors form homogeneous successive layers on the surface. Exposure of the article to one or more of the vapors can be interrupted with a baffle, such that the vapor of only one of the ceramic ingots is directly deposited on a given surface of the article at any instant. The baffle can be employed in conjunction with the article being rotated at a constant or variable speed, and/or being translated above the members within the vessel to alter the relative thicknesses of the ceramic and an intermediate layer that is formed between adjacent layers and is composed of a mixture of the ceramic materials.
摘要:
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.
摘要翻译:一种隔热涂层,适于形成在经受恶劣热环境的制品上,同时受到颗粒和碎屑的侵蚀,如同燃气涡轮发动机的涡轮机,燃烧器和增压器部件的情况。 隔热涂层由沉积在物品表面上的金属粘合层,覆盖粘合层的陶瓷层和分散在陶瓷层内或覆盖陶瓷层的抗侵蚀组合物构成。 接合层用于将绝热陶瓷层牢固地粘附到制品上,而抗侵蚀组合物使得陶瓷层更耐侵蚀。 抗侵蚀组合物是氧化铝(Al 2 O 3)或碳化硅(SiC),而优选的陶瓷层是通过物理气相沉积技术沉积的具有柱状晶粒结构的氧化钇稳定的氧化锆(YSZ)。
摘要:
A thermal barrier coating system and a method for forming the coating system on a component designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The method is particularly directed to a thermal barrier coating system that includes a thermal insulating ceramic layer and a diffusion aluminide bond coat on which an aluminum oxide scale is grown to protect the underlying surface of the component and to chemically bond the ceramic layer. The bond coat is formed to contain an additive metal of platinum, palladium, rhodium, chromium and/or silicon, and an additive element of yttrium and/or zirconium, with possible additions of hafnium. The bond coat may be formed by codepositing aluminum with the active element, or by depositing the additive metal and active element on the surface of the component, and then aluminizing to form the diffusion aluminide bond coat.
摘要:
A bond-coated substrate is protected with an alpha alumina layer. The alpha alumina layer may be deposited as a relatively thick layer directly onto the bond-coated substrate. In this embodiment, no further ceramic layer overlies the alpha alumina layer. Other ceramics may be mixed into the alpha alumina layer, however. In another embodiment, a layer of a ceramic other than alpha alumina is deposited over the bond-coated substrate, and an alpha alumina layer is deposited over the ceramic layer.
摘要:
An improved method for applying a ceramic material, such as a thermal barrier coating to an article. A method for applying a ceramic material as a coating to a substrate article in which the thermal conductivity of the ceramic material is reduced or lowered is provided. The thermal conductivity of a coating applied by a physical vapor deposition (PVD) method is dependent upon its distance from the source(s) of material used for the coating. The thermal conductivity of the applied coating is altered by adjusting the position of the article undergoing the PVD process by increasing the distances of the article or workpiece from the ingot or source of ceramic material to provide a coating of lower thermal conductivity. In accordance with the present invention, the article to be coated is positioned at a distance required to achieve at least a 10% reduction in the thermal conductivity of the applied coating.
摘要:
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.
摘要:
A method for restoring or enhancing an environmental resistant coating of a coating total thickness within a coating design thickness range on a metal substrate of an article includes the application of a restoring or enhancing metal to at least one discrete local surface area. Then at least the discrete local surface area is coated with an environmental resistant coating. For use of the method to restore a coating on an article which has experienced service operation and the discrete surface area includes an undesirable amount of oxidation/corrosion products, the oxidation/corrosion products first are removed from an outer portion of the coating while retaining a coating present at the discrete surface areas and retaining the entire coating on surface areas adjacent the discrete surface areas. Then the restoration metal is applied. For use of the method to enhance an existing coating, at least one discrete surface area is selected based on an oxidation/corrosion attack pattern identified from similar articles which experienced service operation in apparatus of a design for which the article is intended. Then the enhancing metal is applied to the selected area.
摘要:
A thermal barrier coating (TBC) system, comprising a metallic bond coat on an article surface and an outer ceramic TBC is repaired by renewing without removing the bond coat. The outer ceramic TBC is removed to expose a bond coat substrate. At least one discrete local surface area of the article surface subject to bond coat degradation is selected from a thermal pattern unique to the article surface from service operation. At least one renewal metal selected from Pt, Rh, and Pd is applied at least to the selected discrete local surface area and heated to diffuse the renewal metal into the bond coat substrate. An environmental resistant coating selected from aluminides and alloys including aluminum is applied at least to the discrete local surface area over the renewal metal. Thereafter, an outer ceramic TBC is applied to the article surface.
摘要:
An article having a substrate is protected by a thermal barrier coating system. An interfacial layer contacts the upper surface of the substrate. The interfacial layer may comprise a bond coat only, or a bond coat and an overlay coat. The interfacial layer has on its upper surface a preselected, controllable pattern of three-dimensional features, such as grooves in a parallel array or in two angularly offset arrays. The features are formed by an ablation process using an ultraviolet laser such as an excimer laser. A ceramic thermal barrier coating is deposited over the pattern of features on the upper surface of the interfacial layer.