Abstract: An article is described, which includes a metal-based substrate, such as a superalloy; a dense, primary bond layer; and a spongy secondary bond layer. A thermal barrier coating is applied over the secondary bond layer. The spongy layer has a microstructure which includes an open network of interconnected pores. A process is also described. It includes the step of applying a spongy, metallic bond layer over the substrate, followed by the application of a thermal barrier coating. A dense, primary bond layer may optionally be applied before the application of the spongy layer.

Abstract: An article having a spallation resistant TBC comprises a metal substrate, such as a high temperature superalloy, and a TBC, such as a coating of yttria stabilized zirconia. The TBC comprises a plurality of plasma-sprayed layers. The TBC has a coherent, continuous columnar grain microstructure, wherein at least one layer has a plurality of continuous columnar grains which have been extended by directional solidification into an adjacent layer. In a preferred embodiment, the coherent, continuous columnar microstructure comprises substantially all of the volume of TBC. A coherent, continuous columnar grain microstructure is also taught wherein at least some of the plurality of coherent, continuous columnar grains which comprise a TBC extend through essentially the entire thickness of the coating.

Abstract: An article is described, which includes a metal-based substrate, such as a superalloy; a dense, primary bond layer; and a spongy secondary bond layer. A thermal barrier coating is applied over the secondary bond layer. The spongy layer has a microstructure which includes an open network of interconnected pores. A process is also described. It includes the step of applying a spongy, metallic bond layer over the substrate, followed by the application of a thermal barrier coating. A dense, primary bond layer may optionally be applied before the application of the spongy layer.

Abstract: A bond coat and method of forming a bond coat for a thermal barrier coating system are set forth. The bond coat is a roughened bond coat and comprises a layer possessing an uneven, undulated, and irregular surface. The layer is formed of a metal powder mixture disposed on a substrate, such as a turbine component, by high velocity oxygen fuel spraying. The metal powder mixture comprises at least one of a first powder having a first melting point and a second powder having a second melting point that is higher than the first melting point. The bond coat's uneven, undulated, and irregular surface enhances prevention of de-bonding of elements in a thermal barrier coating system.

Abstract: A method for improving the quality of a zirconia-based coating deposited on a metal-based substrate is disclosed. The method comprises the step of plasma-spraying zirconia powder of substantially uniform particle size onto the substrate. The disclosure further relates to an improved powder source material for use in a plasma. The source material is zirconia powder having a uniform particle size, and optionally, a uniform particle density. The use of such a material results in improved thermal barrier coatings for various substrates, such as those found in a turbine engine.

Abstract: An article having a spallation resistant TBC comprises a metal substrate, such as a high temperature superalloy, and a TBC, such as a coating of yttria stabilized zirconia. The TBC comprises a plurality of plasma-sprayed layers. The TBC has a coherent, continuous columnar grain microstructure, wherein at least one layer has a plurality of continuous columnar grains which have been extended by directional solidification into an adjacent layer. In a preferred embodiment, the coherent, continuous columnar microstructure comprises substantially all of the volume of TBC. A coherent, continuous columnar grain microstructure is also taught wherein at least some of the plurality of coherent, continuous columnar grains which comprise a TBC extend through essentially the entire thickness of the coating.

Abstract: A durable coating process which provides improved adhesive bond strength between the coating and its substrate. This process utilizes spray parameters which generate a unique plasma coating that can be applied through a liquid environment between the spray gun nozzle and the substrate to provide combined ion cleaning, etching and activation of the surface to be coated. The improved surface conditioning allows the creation of an exceptionally strong metallurgical bond at the interface between the splattered droplets of the coating material and the substrate. The improved plasma coating process utilizes a relatively short nozzle-to-work surface distance and is therefore suitable for use directly in a liquid such as water in order to keep the substrate from overheating, which may be more likely to occur if the coating were applied in a gas or vacuum environment.

Abstract: A new method is provided for repairing cracks in the outer surfaces of structural parts being a superalloy article having a directionally oriented microstructure, such as a blading member. The article may have internal passageways communicating through the end of the article. The method coats and seals cracked outer-surface areas of directionally solidified and single crystal structures by coating the defective area using a High Velocity Oxy-Fuel process (herein also referred to as HVOF), followed by hot isostatic pressing the part.

Abstract: A method is provided to apply a coating of a superconducting ceramic oxide to a substrate comprising introducing an atomized aqueous solution comprising at least three metal salts into inductively coupled plasma so as to deposit a superconductive ceramic oxide on the substrate, or alternatively, to deposit a mixed metal oxide on the substrate, which is converted into a superconductive ceramic oxide by post-annealing.