Abstract:
Articles suitable for use as high-temperature machine components include a substrate and an environmental barrier coating disposed over the substrate, where the environmental barrier coating includes at least one hermetic self-sealing layer formed from a mixture including an alkaline earth metal aluminosilicate and a rare-earth silicate, and where the at least one hermetic self-sealing layer exhibits substantially no net remnant or residual expansion when subjected to high temperature heat treatment. The environmental barrier coating can further include a bondcoat disposed between the substrate and the hermetic self-sealing layer, a topcoat disposed over the hermetic self-sealing layer, and/or an intermediate layer disposed between the hermetic self-sealing layer and the bondcoat. The intermediate layer can include a barrier material that is substantially inert with respect to silica.
Abstract:
Various embodiments include a gas turbine seal and methods of forming such seal. The method of forming the seal includes forming a freestanding ceramic seal for sealing in a gas turbine by applying a ceramic material on a substrate to form a ceramic layer, removing the substrate from the ceramic layer and finishing the ceramic layer to define the freestanding ceramic seal. The method includes depositing particles of the ceramic material in one of a molten or vapor state on a surface of the substrate and quenching the ceramic material to form the ceramic layer. The ceramic material comprises yttria-stabilized zirconia having a t′ tetragonal structure. A gas turbine including the freestanding ceramic seal is additionally disclosed.
Abstract:
A thermal barrier coating system for metal components in a gas turbine engine having an ultra low thermal conductivity and high erosion resistance, comprising an oxidation-resistant bond coat formed from an aluminum rich material such as MCrAlY and a thermal insulating ceramic layer over the bond coat comprising a zirconium or hafnium oxide lattice structure (ZrO2 or HfO2) and an oxide stabilizer compound comprising one or more of the compounds ytterbium oxide (Yb2O3), yttria oxide (Y2O3), hafnium oxide (HfO2), lanthanum Oxide (La2O3), tantalum oxide (Ta2O5) or zirconium oxide (ZrO2). The invention includes a new method of forming the ceramic-based thermal barrier coatings using a liquid-based suspension containing microparticles comprised of at least one of the above compounds ranging in size between about 0.1 and 5 microns. The coatings form a tortuous path of ceramic interfaces that increase the coating toughness while preserving the ultra low thermal conductivity.
Abstract translation:一种用于具有超低热导率和高耐侵蚀性的燃气轮机中的金属部件的隔热涂层系统,包括由富铝材料如MCrAlY形成的抗氧化粘合涂层和粘结涂层上的绝热陶瓷层 包括锆或铪氧化物晶格结构(ZrO 2或HfO 2)和包含一种或多种化合物氧化镱(Yb 2 O 3),氧化钇(Y 2 O 3),氧化铪(HfO 2),氧化镧(La 2 O 3),钽 氧化物(Ta2O5)或氧化锆(ZrO2)。 本发明包括使用包含由至少一种上述化合物构成的微粒的液体基悬浮液形成陶瓷基热障涂层的新方法,其尺寸范围为约0.1至5微米。 涂层形成陶瓷界面的曲折路径,从而提高涂层韧性,同时保持超低热导率。
Abstract:
Article includes a substrate, a bond coat disposed on the substrate, an environmental barrier coating disposed on the bond coat, and a patterned abradable coating disposed on the second top coat. The environmental barrier coating includes an intermediate layer disposed on the bond coat, a sealing layer disposed on the intermediate layer, a first top coat disposed on the sealing layer, and a second top coat disposed on the first top coat. The first top coat is different from the second top coat.
Abstract:
The present application provides Calcia-Magnesia-Alumina-Silica (CMAS) (or molten silicate) resistant thermal barrier coatings (TBC). The coatings include elongate growth domains of non-equiaxed, randomly arranged overlapping grains or splats. The elongate growth domains include overlapping individual, randomly distributed splats of tough and soft phases. In some embodiments, the elongate growth domains are formed via air plasma spray. In some embodiments, the tough phases are at least partially stabilized zirconia and/or hafnia compositions, and the soft phases are CMAS (or molten silicate) reactive or resistant compositions. Within each elongate growth domain, the mixture of the tough and soft phases act together to limit penetration of CMAS and also provide sufficient domain toughness to minimize cracking forces produced during crystallization of infiltrated CMAS. The soft phases may react with the CMAS and increase its melting point, increase its viscosity, and reduce the destabilization of the tough phases.