Work

Corrosion Behavior of 347H Stainless Steel in NaCl-KCl-MgCl2 Molten Salt: Vapor, Liquid, and Interface Comparison

Year: 2025

Type: article

Abstract: The suitability of 347H stainless steel (SS347H) for chloride salt environments is critical in selecting materials for next-generation concentrated solar power (CSP) systems. This study investigated the corrosion behavior of SS347H in a ton-scale purification system with continuously flowing chloride salt under three conditions: exposure to NaCl-KCl-MgCl2 molten salt vapor, immersion in molten salt, and at the molten salt surface interface. Results revealed that corrosion was most severe in the molten salt vapor, where HCl steam facilitated Cl− reactions with Fe and Cr in the metal, causing dissolution and forming deep corrosion pits. At the interface, liquid Mg triggered displacement reactions with Fe2+/Cr2+ ions in the salt, depositing Fe and Cr onto the surface, which reduced corrosion intensity. Within the molten salt, Mg’s purification effect minimized impurity-induced corrosion, resulting in the least damage. In all cases, the primary corrosion mechanism involves the dissolution of Fe and Cr, with the formation of minor MgO. These insights provide valuable guidance for applying 347H stainless steel in chloride salt environments.

Source: Materials

DOI: 10.3390/ma18143412

Authors: Zhiwen Liu, Huigai Li, Yang Wang, Yanjie Peng, Luyan Sun, Jianping Liang

Institutions: Shanghai University, Chinese Academy of Sciences, Shanghai Institute of Applied Physics

Language: English

Topic: Molten salt chemistry and electrochemical processes

Subfield: Fluid Flow and Transfer Processes

Field: Chemical Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: gold

Estimated APC paid: $3,137