摘要:
A PVD process and apparatus (120) for depositing a coating (132) from multiple sources (110, 111) of different materials. The process and apparatus (120) are particulaity intended to deposit a beta-nickel aluminide coating (132) containing one or more elements whose vapor pressures are lower than NiAl. The PVD process and apparatus (120) entail feeding at least two materials (110, 111) into a coating chamber (122) and evaporating the materials (110, 111) at different rates from separate molten pools (114, 115) thereof. Articles (130) to be coated are suspended within the coating chamber (122), and transported with a support apparatus (118) relative to the two molten pools (114, 115) so as to deposit a coating (132) with a controlled composition that is a mixture of the first and second materials (110, 111).
摘要:
A turbine engine rotor component, such as a compressor or turbine disk or seal element, is protected from corrosion by implanting aluminum or chromium ions, or mixtures thereof, on the surface of the component. Additional metal ions, such as rare earth and reactive elements, may also be implanted on the surface of the component. The component may be heated in a nonoxidizing atmosphere at a specified temperature and time to diffuse the ions into the surface. The component is typically then heated or maintained at an elevated temperature in the presence of oxygen to form an oxide coating on the surface of the component.
摘要:
A surface of a nickel-base article such as an internal surface of a gas turbine airfoil is protected with a donor layer of aluminum and at least one other element. To form the protective layer, a donor alloy is contacted to the protected surface of the article, and simultaneously the article and the donor alloy are heated to a coating temperature that is greater than about 0.7 of the absolute solidus temperature of the donor alloy but is such that the donor alloy remains in the form of a condensed phase contacting the protected surface of the article. The donor alloy is thereafter interdiffused into the protected surface of the article.
摘要:
A method for coating an article includes preparing a coating precursor paint including aluminum-containing pigment particles, a temporary organic binder comprising an acrylic, and a solvent for the temporary organic binder. The coating precursor paint is applied to a surface of the article and thereafter heated to a temperature of from about 1200° F. to about 2100° F. in a non-oxidizing environment.
摘要:
A method for forming a thermal barrier coating system on an article subjected to a hostile thermal environment, such as the hot gas path components of a gas turbine engine. The coating system is generally comprised of a ceramic layer and an environmentally resistant beta phase nickel aluminum intermetallic (&bgr;-NiAl) bond coat that adheres the ceramic layer to the component surface. A thin aluminum oxide scale forms on the surface of the &bgr;-NiAl during heat treatment. The &bgr;-NiAl may contain alloying elements in addition to nickel and aluminum in order to increase the environmental resistance of the &bgr;-NiAl. The &bgr;-NiAl powder having a size in the range of 20-50 microns is applied using air plasma spray techniques to produce a surface having a roughness of 400 microinches or rougher. The ceramic top coat can be applied using inexpensive thermal spray techniques to greater thicknesses than achievable otherwise because of the rough surface finish of the underlying &bgr;-NiAl bond coat.
摘要:
An internal passage of an article such as a gas turbine airfoil is coated with an aluminum-containing coating. To accomplish this coating process, a coating slurry of a mixture of a carrier component of water and a hectorite clay or a bentonite clay, together with a solids component of a source of aluminum, a halide activator, and an oxide dispersant, is prepared. The coating slurry is applied to the internal passage of the gas turbine airfoil and dried. The gas turbine airfoil and the applied coating slurry are heated to form an aluminum-containing coating bonded to the internal passage of the gas turbine airfoil. Excess coating material is removed from the article internal passage.
摘要:
Methods for improving mechanical properties of beta processed, alpha-beta titanium alloy articles involving forging the alloy article above the beta transus to produce a post final forged article, subjecting the post final forged article to a post-forged cooling process to produce a post-forged cooled article, solution heat treating the post-forged cooled article to a temperature below the beta transus to produce a solution heat treated article, subjecting the solution heat-treated article to a controlled post-solution cooling process to produce a post-solution cooled article, and alpha phase precipitation treating the post-solution cooled article to obtain a final article having an average elongation value of at least about 3%.
摘要:
Methods for making a reinforced refractory crucible for melting titanium alloys including providing a form, applying a facecoat to the form, the facecoat having at least one facecoat layer, applying a backing about the facecoat, the backing having at least one backing layer, applying at least one reinforcing element to at least a portion of the facecoat layer, the backing layer, or a combination thereof where the reinforcing element includes at least one composition selected from ceramic compositions, metallic compositions, and combinations thereof.
摘要:
A composition comprising a glass-forming binder component and a particulate corrosion resistant component. The particulate corrosion resistant component comprises corrosion resistant particulates having: a CTEp of at least about 4 and being solid at a temperature of about 1300° F. (704° C.) or greater; and a maximum median particle size defined by one of the following formulas: (a) for a CTEp of 8 or less, an Mp equal to or less than (4.375×CTEp)−10; and (b) for a CTEp of greater than 8, an Mp equal to or less than (−4.375×CTEp)+60, wherein CTEp is the average CTE of the corrosion resistant particulates and wherein Mp is the median equivalent spherical diameter (ESD), in microns, of the corrosion resistant particulates. Also disclosed is an article comprising a turbine component comprising a metal substrate and a corrosion resistant coating overlaying the metal substrate, as well as a method for forming at least one layer of the corrosion resistant coating adjacent to the metal substrate. The corrosion resistant coating has a maximum thickness defined by one of the following formulas: (3) for a CTEp of 8 or less, an Tc equal to or less than (1.5×CTEp)−3.5; and (4) for a CTEp of greater than 8, an Tc equal to or less than (−1.5×CTEp)+20.5, wherein Tc is the thickness, in mils, of the corrosion resistant coating.
摘要:
A gas turbine component, such as a turbine disk or a turbine seal element, is protected by depositing an oxide coating on the gas turbine component. The deposition is performed by a vapor deposition process such as metal-organic chemical vapor deposition (MOCVD) to a coating thickness of from about 0.2 to about 50 micrometers, preferably from about 0.5 to about 3 micrometers. The deposited oxide may be an oxide of aluminum, silicon, tantalum, titanium, and chromium.