| 摘要 |
A process by which a nickel-based superalloy substrate (20) prone to deleterious reactions with an aluminum-rich coating (22) can be stabilized by carburization. The process generally entails processing the surface of the substrate (20) to be substantially free of oxides, heating the substrate (20) in a non-oxidizing atmosphere to a carburization temperature, and then contacting the surface of the substrate (20) with a carburization gas mixture comprising a diluted low activity hydrocarbon gas while maintaining the substrate (20) at the carburization temperature. While at the carburization temperature and contacted by the carburization gas, carbon atoms in the carburization gas dissociate therefrom, transfer onto the surface of the substrate (20), diffuse into the substrate (20), and react with refractory metals within the substrate (20) to form refractory metal carbides (36) within a carburized region (38) beneath the surface of the substrate (20). The substrate (20) is then cooled in a non-oxidizing atmosphere to terminate carbide formation. |
