| 摘要 |
A masking material and a method for applying the masking material to preselected surfaces of a component to protect the surfaces to which the masking material is applied from exposure to a vapor phase of aluminum gas while a protective environmental coating is applied to other surfaces of the component. The component, such as found in the hot section of a gas turbine engine, typically has intricate internal passageways. A ceramic material is applied as a mask over preselected surfaces while leaving remaining surfaces of a component exposed. The component typically is a superalloy component, and the exposed surfaces are to be coated with an environmental protective coating. The surfaces are preselected on the basis of whether coating is desired on the surface. The ceramic material forms a continuous, crack-free mask on these preselected surfaces without obstructing the internal passageways. The ceramic material which forms a mask is stable at the elevated temperatures of environmental coating application. The ceramic mask material must be continuous and substantially crack-free to prevent the penetration of the aggressive gas phase of the environmental coating material onto the surface of the component where it would otherwise undesirably be deposited. The ceramic material does not react with either the surface of the superalloy component or the gaseous vapors of the coating composition. At the conclusion of the coating operation, the ceramic coating applied as a mask can be easily and completely removed from the surface of the substrate by simple mechanical means, which surface is free of any coating from the coating operation.
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