An article that includes a substrate; a first layer including yttria and zirconia or hafnia, where the first layer has a columnar microstructure and includes predominately the zirconia or hafnia; a second layer on the first layer, the second layer including zirconia or hafnia, ytterbia, samaria, and at least one of lutetia, scandia, ceria, neodymia, europia, and gadolinia, where the second layer includes predominately zirconia or hafnia, and where the second layer has a columnar microstructure; and a third layer on the second layer, the third layer including zirconia or hafnia, ytterbia, samaria, and a rare earth oxide including at least one of lutetia, scandia, ceria, neodymia, europia, and gadolinia, where the third layer has a dense microstructure and has a lower porosity than the second layer.

A coating system disposed on a surface of a substrate is provided. The coating system includes a bond coating on the surface of the substrate, a protective coating on the bond coating, a thermal barrier coating on the protective coating, and a protective agent disposed within at least some of the voids of the thermal barrier coating. The protective coating is constructed from a ceramic material, and the thermal barrier coating defines a plurality of elongated surface-connected voids. Methods are also generally provided for forming such a coating system.

In accordance with the present disclosure, there is provided a process for limiting a critical stabilizer content in coatings comprising placing a source coating material in a crucible of a vapor deposition apparatus having a coating chamber, the source coating material having compositional range of LnO.sub.1.5 comprising a single cation mol % of 30-50% relative to zirconia (ZrO.sub.2), where Ln=La, Pr, Nd, Sm, Eu, Gd, and Tb and combinations thereof; energizing the source coating material with an electron beam that delivers a power density to the material in the crucible forming a vapor cloud from the source coating material; and depositing the source coating material as a coating system onto a surface of a work piece.

A thermal barrier coating includes a highly porous layer and a dense layer. The highly porous layer is formed on a heat-resistant base, is made of ceramic, has pores, has a layer thickness of equal to or larger than 0.3 mm and equal to or smaller than 1.0 mm, and has a pore ratio of equal to or higher than 1 vol % and equal to or lower than 30 vol %. The dense layer is formed on the highly porous layer, is made of ceramic, has a pore ratio of equal to or lower than 0.9 vol % that is equal to or lower than the pore ratio of the highly porous layer, and has a layer thickness of equal to or smaller than 0.05 mm.

Advanced environmental barrier coating bond coat systems with higher temperature capabilities and environmental resistance are disclosed. These bond coat systems can be applied to ceramic substrates such as SiC/SiC ceramic matrix composite substrates, and can provide protection from extreme temperature, mechanical loading and environmental conditions, such as in high temperature gas turbines. Example bond coat systems can include either an advanced silicon/silicide component, an oxide/silicate component, or a combination thereof.

A rotating component includes an airfoil section with a free end, the airfoil section being formed of a composite core with a metallic skin and an abrasive coating applied to the free end.

A thermal spray material that exhibits improved thermal conductivity and solid particle erosion resistance is provided for thermal barrier coatings. The thermal spray material forms a thermally stable coating when thermally sprayed. The coating includes at least one phase that exhibits improved thermal conductivity and at least one phase that exhibits improved solid particle erosion resistance.

A coating method includes depositing a slurry including a coarsely particulate ceramic and a finely particulate ceramic on a base material configured with an oxide-based ceramics matrix composite such that a proportion of coarse particles decreases towards a surface of the base material; forming a bond coating by performing a heat treatment on the base material on which the slurry has been deposited; and forming a top coating by thermally spraying a ceramic onto the bond coating. The oxide-based ceramics matrix composite is an alumina silica type oxide-based ceramics matrix composite. The coarsely particulate ceramic and the finely particulate ceramic are alumina-based powder.

An article includes a substrate, a bond coat layer disposed on the substrate, and a layer of networked ceramic nanofibers disposed on the bond coat layer.

An article includes a substrate, a ceramic barrier coating, and a layer of networked ceramic nanofibers. The ceramic barrier coating is disposed on the substrate and has a porous columnar microstructure. The layer of networked ceramic nanofibers is disposed on the ceramic barrier layer and seals the pores of the porous columnar microstructure.