A process for forming an oxidation and corrosion resistant coating on selective surfaces of an airfoil providing a chamber having an external wall which receives a hollow sleeve for defining an internal space and an annular space between the external wall and sleeve. The airfoil to be coated is located within the internal space. An activator is provided in the internal space below the airfoil. The chemical coating composition is located in the annular space. The chamber is closed and heated to a desired temperature for a sufficient time to coat selective surfaces of the airfoil with the coated composition.
CROSS REFERENCE TO RELATED APPLICATION(S)
This application is a divisional application of U.S. Ser. No. 08/870,805 filed Jun. 6, 1997, entitled CAN COATING SYSTEM, by Terry T. Perry et al now U.S. Pat. No. 5,910,219.
A method for introducing an inert carrier gas into a coating container used to provide a metallic coating on articles. The method includes introducing the inert carrier gas into the coating container as a plurality of carrier gas streams proximate the top of the coating container. The carrier gas streams are formed and introduced into the coating container before encountering a source material for the metallic coating, and each carrier gas stream is introduced so that the inert carrier gas at least initially moves within the coating container in a circular swirling fashion above and before encountering the source material and the article.
A gas distributor suitable for introducing a carrier gas at the top of a coating container used to provide a metallic coating on articles. The gas distributor includes a gas inlet and a gas outlet head in communication with the gas inlet for receiving a flow of gas from the gas inlet. A plurality of gas outlets through which the gas flow exits as a gas stream are spaced along the peripheral surface of the gas outlet head. A plurality of gas deflectors, each proximate to one of the gas outlets, at least initially direct the gas stream exiting the gas outlet in at least a generally centripetal path. This gas distributor can be used in vapor coating apparatus having a coating container, at least one holder for each article to be coated positioned within the coating container and below the gas outlet head of the gas distributor and at least one holder for the source of the metallic coating positioned within the coating container and below the gas outlet head of the gas distributor. A method is also provided for introducing the carrier gas as a plurality of carrier gas streams proximate the top of the coating container so that each carrier gas stream flows at least initially in at least a generally centripetal path, as well as a method for coating the articles with a metallic coating in the coating container.
A method for applying an aluminide coating on a gas turbine engine blade having an external surface and an internal cooling cavity having an internal surface that is connected to the external surface by cooling holes. The method is conducted in a vapor coating container having a hollow interior coating chamber, and includes the steps of loading the coating chamber with the blade to be coated; providing an aluminide coating gas in the loaded coating chamber; maintaining the loaded coating chamber comprising the aluminide coating gas at a specified temperature and time to deposit an aluminide coating on the external surface of the blade; and then flowing an inert carrier gas into the loaded coating chamber comprising the aluminide coating gas at a specified gas flow rate and time to move the aluminide coating gas through the cooling holes and internal cooling cavity and deposit an aluminide coating on the internal surface of the blade.
A method for applying an aluminide coating on a gas turbine engine blade having an external surface and an internal cooling cavity having an internal surface that is connected to the external surface by cooling holes. The method is conducted in a vapor coating container having a hollow interior coating chamber, and includes the steps of loading the coating chamber with the blade to be coated; providing an aluminide coating gas in the loaded coating chamber; flowing an inert carrier gas into the loaded coating chamber comprising the aluminide coating gas at a specified gas flow rate and time to move the aluminide coating gas through the cooling holes and internal cooling cavity and deposit an aluminide coating on the internal surface of the blade; and then flowing an inert carrier gas into the loaded coating chamber comprising the aluminide coating gas at a specified higher temperature and time to deposit an aluminide coating on the external surface of the blade.
A bond coat process for thermal barrier coatings. The method includes, after cleaning and masking the external surface of the substrate, first applying a layer of NiCrZr alloy to the external surface of the substrate using a sputter coat or other suitable process. Aluminum is then applied to the substrate, using either a vapor phase aluminization (VPA) or chemical vapor deposition (CVD) process, wherein aluminum diffuses into the NiCrZr alloy layer wherein a diffusion layer is formed by the aluminum with the substrate material on the internal surface of the substrate. The coated substrate may then be subjected to a heat treatment in a protective atmosphere to further allow diffusion of the aluminide into the NiAlCrZr diffusion layer. The substantially Al outer layers of the NiAlCrZr diffusion layer, and the diffusion aluminide layer, will provide an aluminum source for the surface, which will oxidize to form a tightly adherent aluminum scale. The diffusion aluminide layer and the high Al portion of the NiAlCrZr diffusion layer will also function as a source of aluminum which will provide a reservoir to heal the alumina scale during operation.
