Corrosion behavior of Ni-based alloys in NaCl-KCl-MgCl₂ molten salts based on cellular automata simulation

Chloride molten salts is considered as a promising heat storage material in next generation solar thermal power generation systems. However, their corrosive effects on alloys cannot be overlooked. In this paper, a 2D cellular automata (CA) corrosion model based on the corrosion mechanisms of Ni-based alloys in NaCl-KCl-MgCl₂ molten salt is established, and the simulated evolution rules of the corrosion process are defined. Based on the model, the corrosion extent, the evolution of the internal structure, and the distribution of Cr elements are revealed and compared with experimental values. The effects of key parameters on corrosion rate are also investigated. The results show that corrosion rate is positively correlated with the concentrations of Cl₂ and O₂, and negatively correlated with the concentrations of Mg(OH)Cl, Cr and the main reaction probability P_r12. Orthogonal experiment results show that the influence order of parameters on corrosion rate in turn is the concentrations of Cl₂, Mg(OH)Cl, O₂, Cr, and P_r12. When the parameter takes the optimal value, the corrosion rate is 1.532 × 10³ μm/y, which is reduced by up to 17.7 % compared with the original conditions. This approach is applicable to studying the corrosion behavior of Ni-based alloys in NaCl-KCl-MgCl₂ molten salts, and provides significant insights into the corrosion mechanisms of alloys.