Hot Corrosion Performance of Inconel 625 in 60% NaNO₃–40% KNO₃ at 550°C: A Study for Sustainable Energy Systems

ABSTRACT The use of concentrated solar power (CSP) structures is raising owed to the expanding claim for sustainable energy. Thermal energy storage (TES) acts a valuable function in focusing this issue. The present study investigated the high temperature corrosion behaviour of Inconel 625 for CSP structural applications exposed to a hot corrosion condition of 60% NaNO₃–40% KNO₃ solar salt at 550°C. The corrosion behaviour of the substrate was estimated at several intervals varying from 100 to 500 h. The corrosion kinetics were estimated through the weight variation process, and the degradation of the specimens was studied through field‐emission scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and X‐ray diffraction analysis. The results confirm that initial corrosion resistance is controlled by a protective Cr₂O₃ layer, while prolonged exposure leads to Cr depletion, oxide breakdown, and formation of non‐protective MoO₃ and Fe₂O₃. The growth of NiCr₂O₃ specifies good corrosion resistance around a 400‐h interval. The study provides key insights into material selection and durability for TES containers in CSP applications.