부산대학교 도서관

The halide-activated pack cementation process has been used to grow corrosion-resistant diffusion coatings for a variety of traditional and advanced materials. Further understanding of the thermodynamics for packs activated by a selected pair of halide salts has led to the codeposition of two elements to form adherent coatings with compositions resistant to cyclic oxidation and other corrosion attack. The coating method has been applied in various novel ways to protect advanced materials. For example, different schemes are presented to create effective coatings for the application of materials for hot-gas cleanup and heat-exchanger tubes in combined-cycle coal-fired power generating systems. Likewise, developmental refractory-metal aluminides have been protected by either aluminizing or siliciding. The protection of Mo by a pack-grown Mo(Si,Ge){sub 2} coating may eliminate the occurrence of pesting in low-temperature oxidation. Traditional steels for boiler applications can be protected by the codeposition of Cr and Si to grow a ferrite surface layer with an approximate composition of Fe-25Cr-3Si. Alternatively, the codeposition of Al and Cr can yield a very corrosion-resistant composition of Fe{sub 3}(Al,Cr).