摘要:
A process for forming a diffusion aluminide-hafnide coating on an article, such as a component for a gas turbine engine. The process is a vapor phase process that generally entails placing the article in a coating chamber containing a halide activator and at least one donor material. The donor material collectively consists essentially of at least 0.5 weight percent hafnium and at least 20 weight percent aluminum with the balance being chromium and/or cobalt.
摘要:
A thermal barrier coating system and a method for forming the coating system on a component designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The coating system includes a diffusion aluminide bond coat whose oxide growth rate is significantly reduced to improve the spallation resistance of a thermal barrier layer by forming the bond coat to include a dispersion of aluminum, chromium, nickel, cobalt and/or platinum group metal oxides. The oxides preferably constitute about 5 to about 20 volume percent of the bond coat. A preferred method of forming the bond coat is to initiate a diffusion aluminizing process in the absence of oxygen to deposit a base layer of diffusion aluminide, and then intermittently introduce an oxygen-containing gas into the diffusion aluminizing process to form within the bond coat the desired dispersion of oxides. Thereafter, a ceramic layer is deposited on the bond coat to form a thermal barrier coating.
摘要:
A process for reclaiming aluminum alloy donor from a vapor phase deposition process used to form a diffusion aluminide coating on a component, such as the high-temperature superalloy components of gas turbine engines. The process generally entails recycling a particulate aluminum alloy donor material that, as a result of having been used as the donor material for depositing a diffusion aluminide coating on an article by vapor phase deposition, particles of the donor material comprise an aluminum alloy core encased in an aluminum-depleted shell. The process generally entails tumbling the donor material in a manner that removes the aluminum-depleted shell, followed by sieving the donor material to remove shell fragments and undersized particles.
摘要:
A high temperature vapor coating container, including a hollow interior, resists distortion and cracking at a vapor coating temperature of at least about 1700.degree. F. as a result of making the container of a nonmetallic material having a coefficient of thermal expansion of less than about 4.5.times.10.sup.-6 at the vapor coating temperature, the material being nonreactive with the coating vapor at the vapor coating temperature.
摘要:
Apparatus and method to improve vapor phase diffusion coating of articles. The apparatus provides a barrier to segregate the portion of the article requiring coating from the portion of the article not requiring coating. The fixture is reusable, being unaffected by the coating gases. The fixture reduces the exposure of the coating gases with the portion of the article not requiring coating. By use of an optional seal, the portion of the article not requiring coating can be isolated from the coating gases.
摘要:
A thermal barrier coating system and a method for forming the coating system on a component designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The coating system includes a diffusion aluminide bond coat whose oxide growth rate is significantly reduced to improve the spallation resistance of a thermal barrier layer by forming the bond coat to include a dispersion of aluminum, chromium, nickel, cobalt and/or platinum group metal oxides. The oxides preferably constitute about 5 to about 20 volume percent of the bond coat. A preferred method of forming the bond coat is to initiate a diffusion aluminizing process in the absence of oxygen to deposit a base layer of diffusion aluminide, and then intermittently introduce an oxygen-containing gas into the diffusion aluminizing process to form within the bond coat the desired dispersion of oxides. Thereafter, a ceramic layer is deposited on the bond coat to form a thermal barrier coating.
摘要:
Apparatus and method to improve vapor phase diffusion coating of articles. The apparatus provides a barrier to segregate the portion of the article requiring coating from the portion of the article not requiring coating. The fixture is reusable, being unaffected by the coating gases. The fixture reduces the exposure of the coating gases with the portion of the article not requiring coating. By use of an optional seal, the portion of the article not requiring coating can be isolated from the coating gases.
摘要:
A process for forming a diffusion aluminide coating on a substrate, such as a component for a gas turbine engine. The process generally entails placing the substrate in a suitable coating chamber, flowing an inert or reducing gas into and through the coating chamber, and then aluminizing the substrate using an aluminizing technique with a substantially constant aluminum activity, such as a vapor phase deposition process. During the aluminizing process, the amount of unreacted aluminum within the coating chamber is controlled by altering the flow rate of the gas through the coating chamber so that a portion of the unreacted aluminum is swept from the coating chamber by the gas. The amount of unreacted aluminum swept from the coating chamber is regulated by metering the gas flow rate in order to control the aluminizing rate and aluminum content of the resulting aluminide coating.
摘要:
A process for forming a diffusion aluminide coating on an article, such as a component for a gas turbine engine. The process is a vapor phase process that generally entails placing the article in a coating chamber containing an aluminum donor material, without any halide carrier or inert filler present. The aluminum donor material consists essentially of about 20 to about 70 weight percent aluminum, with the balance being chromium or cobalt. While the article is held out of contact with the donor material, coating is initiated in an inert or reducing atmosphere by heating the article and the donor material to vaporize the aluminum constituent of the donor material, which then condenses on the surface of the article and diffuses into the surface to form a diffusion aluminide coating on the article.
摘要:
A method for making an engine component with a hollow interior includes the steps of: selectively patterning a principal substrate surface; forming a slurry including a selected amount of a binder material, a selected amount of a solvent and a selected amount of a filter material; inserting the slurry into the substrate surface pattern; evaporating the solvent to solidify the slurry; depositing a close-out layer of material over the patterned substrate surface and over the solidifed slurry; and without removing the close-out layer, removing the solidified slurry to provide a structure with a hollow interior.