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Pack Aluminizing of Selected Pure Metals - A Comparative Study
Surface modification is an effective approach to extend the lifetime of metallic alloys in corrosive environments. Halide activated pack cementation (HAPC) is a cost-effective process that can produce corrosion-resistant surfaces, e.g., aluminum-rich coatings. Upon oxidation, the aluminide coatings form a protective oxide layer on the underlying alloy. This process can be applied to a broad range of commercially available metals; however, the effective utilization of this process requires a fundamental understanding of different aspects, e.g., the role of the substrate. In this study, the effect of coating parameters, i.e., temperature, time and pack compositions, on the coating characteristics for pure metals - iron, nickel, cobalt and titanium, were examined. These metals are the basis of many commonly used engineering alloys. Each of these metals have different crystal structures, and three out of four undergo allotropic solid-state transformations. A comparative analysis of the different coating - substrate combinations and their variables will be presented.