摘要:
A thermal barrier coating (TBC) for a component intended for use in a hostile environment, such as the superalloy turbine, combustor and augmentor components of a gas turbine engine. The TBC is formed of zirconia that is partially stabilized with yttria (YSZ), preferably not more than 3 weight percent yttria, and to which one or more additional metal oxides are alloyed to increase crystallographic defects and lattice strains in the TBC grains and/or form precipitates of zirconia and/or compound(s) of zirconia and/or yttria and the additional metal oxide(s), the inclusion of which reduces the thermal conductivity of the YSZ to levels lower than conventional 6-8% YSZ. Improvements are particularly contemplated for TBC having a columnar grain structure, such as those deposited by EBPVD and other PVD techniques.
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 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 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 thermal barrier coating (TBC) for a component intended for use in a hostile environment, such as the superalloy turbine, combustor and augmentor components of a gas turbine engine. The TBC is formed to contain small amounts of alumina precipitates dispersed throughout the grain boundaries and pores of the TBC to getter oxide impurities that would otherwise allow or promote grain sintering and coarsening and pore coarsening, the consequence of which would be densification of the TBC and therefore increased thermal conductivity. If sufficiently fine, the precipitates also serve to pin the grains and pore boundaries of the TBC, the effect of which is to reduce the tendency for the microstructure of the TBC to sinter, coarsen and undergo pore redistribution, which also increase thermal conductivity of the TBC 26.
摘要:
A thermal barrier coating (TBC) and method for forming the coating on a component intended for use in a hostile environment. The coating and method are particularly directed to inhibiting sintering, grain coarsening/growth and pore redistribution in the coating during high temperature excursions by providing limited amounts of extremely fine carbide-based and/or nitride-based precipitates preferably formed at defects and pores at and between the grain boundaries of the TBC microstructure. The precipitates pin the TBC grain boundaries and pores during high temperature excursions, with the effect that the TBC microstructure is thermally stabilized. A coating containing the carbides and/or nitrides can be formed using a physical vapor deposition technique in an atmosphere that contains carbon and/or nitride gases or compounds thereof, or by evaporating a source material that contains carbon, carbon-containing compounds, carbides and/or nitrides.
摘要:
A coating and process for depositing the coating on a substrate. The coating is a nickel aluminide overlay coating of predominantly the beta (NiAl) and gamma-prime (Ni3Al) intermetallic phases, and is suitable for use as an environmental coating and as a bond coat for a thermal barrier coating (TBC). The coating can be formed by depositing nickel and aluminum in appropriate amounts to yield the desired beta+gamma prime phase content. Alternatively, nickel and aluminum can be deposited so that the aluminum content of the coating exceeds the appropriate amount to yield the desired beta+gamma prime phase content, after which the coating is heat treated to diffuse the excess aluminum from the coating into the substrate to yield the desired beta+gamma prime phase content.
摘要:
A coating and process for depositing the coating on a substrate. The coating is a nickel aluminide overlay coating of predominantly the beta (NiAl) and gamma-prime (Ni3Al) intermetallic phases, and is suitable for use as an environmental coating and as a bond coat for a thermal barrier coating (TBC). The coating can be formed by depositing nickel and aluminum in appropriate amounts to yield the desired beta+gamma prime phase content. Alternatively, nickel and aluminum can be deposited so that the aluminum content of the coating exceeds the appropriate amount to yield the desired beta+gamma prime phase content, after which the coating is heat treated to diffuse the excess aluminum from the coating into the substrate to yield the desired beta+gamma prime phase content.
摘要翻译:用于将涂层沉积在基材上的涂层和方法。 涂层是主要是β(NiAl)和γ-prime(Ni 3 Al 3 Al)金属间相的镍铝化物覆盖涂层,并且适合用作环境涂层和作为粘合涂层 隔热涂层(TBC)。 可以通过以适当的量沉积镍和铝来形成所述涂层,以产生所需的β+γ初相相含量。 或者,可以沉积镍和铝,使得涂层的铝含量超过适当的量以产生所需的β+γ初相相含量,之后热处理涂层以将过量的铝从涂层扩散到基底中 产生期望的β+γ'相相含量。
摘要:
A process for forming a beta-phase nickel aluminide (NiAl) overlay coating that is suitable for use as a bond coat for a thermal barrier coating (TBC). The overlay coating is deposited by a method that produces a generally columnar grain structure in which grains extend through the coating such that at least some grain boundaries are open at the coating surface. The coating is then peened with a particulate media, followed by heating the overlay coating to a temperature sufficient to cause the overlay coating to recrystallize and form new grain boundaries that are not open to the outer surface of the coating and significantly less susceptible to accelerated oxidation than the original grain boundaries. The particulate media is formed of a composition containing nickel and aluminum, such that an oxide scale that forms on the surface of the coating after the peening operation is substantially free of deleterious oxide compounds, notably iron-containing spinels.
摘要:
A process for forming diffusion aluminide coatings on an uncoated surface of a substrate, without interdiffusing a sufficient amount of aluminum into a coating layer to adversely affect the coating growth potential and mechanical properties of said coating layer. A metal substrate is provided comprising an external surface and an internal passage therein defined by an internal surface, at least a portion of the external surface of the substrate being coated with a coating layer selected from the group consisting of β-NiAl-base, MCrAlX, a line-of-sight diffusion aluminide, a non-line-of-sight diffusion aluminide, a pack diffusion aluminide, and a slurry diffusion aluminide on said substrate. The metal substrate is subjected to an aluminum vapor phase deposition process.