Abstract:
An apparatus (50) and method for casting an alloy using a unidirectional casting technique. The apparatus (50) includes a mold (52) adapted to contain a molten quantity (56) of an alloy, a primary heating zone (60) adapted to heat the mold (52) and the molten alloy therein to a temperature above the liquidus temperature of the alloy, a cooling zone (64) adapted to cool the mold (52) and molten alloy therein to a temperature below the solidus temperature of the alloy and thereby yield the unidirectionally-solidified casting, and an insulation zone (62) between the primary heating zone (60) and the cooling zone (64). The apparatus (50) also has a secondary heating zone (66) separated from the insulation zone (62) by the primary heating zone (60). The secondary heating zone (66) maintains the mold (52) and the molten alloy therein at a temperature below the liquidus temperature of the alloy. The temperatures within the primary and secondary heating zones (60,66) are individually set and controlled.
Abstract:
In an exemplary embodiment, a high temperature oxidation and hot corrosion resistant MCrAlX alloy is disclosed, wherein, by weight of the alloy, M comprises nickel in an amount of at least about 30 percent and X comprises from about 0.005 percent to about 0.19 percent yttrium. In another exemplary embodiment, a coated article is disclosed. The article includes a substrate having a surface. The article also includes a bond coat disposed on the surface, the bond coat comprising a high temperature oxidation and hot corrosion resistant MCrAlX alloy, wherein, by weight of the alloy, M comprises at least about 30 percent nickel and X comprises about 0.005 percent to about 0.19 percent yttrium.
Abstract:
A method for brazing a component (70) in a power generation system (10), the brazed power generation system component (202), and braze (200) are provided to improve repairing power generation systems (10). The method includes providing the component (70) having a feature (76) in a surface (72) of the component (70) and coating (703) a particulate material (90) with a filler material (92) to obtain a coated particulate material (94). The method includes preparing the feature (76) to obtain a treatment area (80) and filling the treatment area (80) in the surface (72) of the component (70) with the coated particulate material (94). The method includes heating the treatment area (80) and surrounding component (70) to a brazing temperature and applying oxidation protection (110) to the treatment area (80). After the brazing temperature is obtained, the method includes brazing the treatment area (80) and the screen and cooling the component (70) to obtain a brazed joint (200).
Abstract:
A coating system and process capable of providing erosion and corrosion-resistance to a component (18), particularly a steel compressor blade of an industrial gas turbine. The coating system includes a metallic sacrificial undercoat (12) on a surface of the component substrate (16), and a ceramic topcoat (14) deposited by thermal spray on the undercoat (12). The undercoat (12) contains a metal or metal alloy that is more active in the galvanic series than iron, and electrically contacts the surface of the substrate. The ceramic topcoat (14) consists essentially of a ceramic material chosen from the group consisting of mixtures of alumina and titania, mixtures of chromia and silica, mixtures of chromia and titania, mixtures of chromia, silica, and titania, and mixtures of zirconia, titania, and yttria.
Abstract:
A method for preparing a coated nickel-base superalloy article reduces the sulfur content of the surface region of the metallic coating layers to low levels, thereby improving the adhesion of the coating layers to the article. The method includes depositing (52) a first layer (70) of platinum overlying the surface of a substrate (32), depositing (58) a second layer (76) of aluminum over the platinum, and final desulfurizing (60) the article by heating the article to elevated temperature, preferably in hydrogen, and removing (62) a small amount (78) of material from the surface that was exposed during the step of heating. A ceramic layer (40) may be deposited (64) over the desulfurized article. The article may also be similarly desulfurized at other points in the fabrication procedure.
Abstract:
A coating system, coated article and method are provided which yield a thermal barrier coating (26) having good adhesion to a bond coat (24) overlying a metal superalloy substrate (22). The adhesion of the bond coat (24) and the thermal barrier coating (26) (TBC) is achieved by formation of a mature α-Al 2 0 3 (rhombohedral) scale (28) at the bond coat/TBC interface. The adhesion of the thermal barrier coating (26) to the bond coat (24) is enhanced by utilizing one or more of the following steps (1) preoxidation of the bond coat (24), (2) inoculation of the surface of the bond coat (24), (3) surface doping of the bond coat surface, and (4) the addition of noble metals. The above step improves the formation of α-Al 2 0 3 which improves the adhesion of the TBC to the bond coat by avoiding undesired oxide phase transformations.
Abstract translation:提供一种涂覆系统,涂层制品和方法,其产生对覆盖在金属超耐热合金基板(22)上的粘合涂层(24)具有良好粘附性的热障涂层(26)。 通过在粘合涂层/ TBC界面处形成成熟的α-Al 2 O 3(菱形)标度(28)来实现粘合涂层(24)和热障涂层(26)(TBC)的粘附。 通过利用以下一个或多个步骤(1)预先氧化粘合涂层(24),(2)接合表面的粘合剂来增强热障涂层(26)对粘结涂层(24)的粘合性 涂层(24),(3)表面掺杂粘合涂层表面,和(4)添加贵金属。 上述步骤改善了α-Al 2 O 3的形成,其通过避免不期望的氧化物相变而改善了TBC对粘结层的粘合性。