Pulsed-vapor phase aluminide process for high temperature oxidation-resistant coating applications

摘要

An improved process for applying aluminide coatings to superalloy components used in gas turbine applications resulting in a more uniform coating with less hazardous waste by-products. The process involves the steps of placing the superalloy components into a retort with an aluminum-containing source, evacuating air from the retort and introducing an inert gas, heating the retort to a preselected temperature, while maintaining the preselected temperature purging the inert gas from the retort by introducing hydrogen gas, while maintaining the preselected temperature, pulsing, by reducing the retort pressure to a preselected pressure below atmospheric pressure, followed by introducing a halide-containing gas to react with the aluminum-containing source to create an aluminum-rich vapor that deposits aluminum on the components, then reintroducing hydrogen gas into the retort to purge the gases within the retort; and cooling the retort.