Modeling of Surface Modification of Stainless Steel by Halide Activated Pack Cementation Method

Abstract

In high-temperature applications, ferrous-based materials are important due to their excellent combination of desirable mechanical properties, ease of production, corrosion resistance at room temperature and cost-effectiveness. However, mechanical properties must be optimized against environmental effects. Depending on the industrial applications, various corrosion types may also occur. An approach to preserve the mechanical properties of the structural alloy being protected against corrosion is the application of protective coatings to the surfaces. Diffusion coatings are an effective method to obtain corrosion, oxidation and abrasion resistance against detrimental conditions of high temperature. According to the literature, the halide activated pack cementation method has been widely used for ferrous-based materials for a long time. However, most studies concerned with developing coating applications are based on experimental investigations that include microscopic, chemical, and mechanical analyses. Limited studies have been conducted based on computational alloy approaches. In this study, Cr coating of the AISI 316L steel by halide activated pack cementation method was considered as a diffusional problem and the kinetics of the coating deposition process were examined. The effect of process variables such as temperature, time and the compositions of coating layers formed on the surfaces were investigated thermodynamically with Thermo-Calc software and kinetically with DICTRA module. This approach provides insight into the dependence of solid-state diffusions on the processing parameters, and a better understanding of the phases that form along the coating and substrate material.