Intergranular corrosion (IGC) of Nb-Ti stabilized ferritic stainless steel (FSS) 429 was investigated using the double loop electrochemical potentiokinetic reactivation (DL-EPR) test combined with the microstructure observation. The results indicated that the optimized DL-EPR test condition for FSS 429 was the solution of 0.5 M H2SO4+ 0.0001 M KSCN with a scanning rate of 100 mV/min at 30°C. Based on this condition, the specimens aging at 400–700°C for different duration were tested and a time-temperature-sensitization (TTS) curve for FSS 429 was obtained, which reveals the sensitization nose was located around 550°C. The criticalIr/Iavalue was determined to be about 3% above which IGC occurred. After aging treatment, Cr depletion zone was detected using energy dispersive spectroscopy (EDS), most possibly due to Cr segregation around intergranular TiC and NbC.

With the emergence of the concentrating solar power (CSP) technology, the corrosion behaviors of potential materials applied in thermal energy transfer and storage system attract tremendous attentions. Corrosion behaviors of X80 carbon steel, 304, 316L stainless steels, and 600, 825 nickel alloys in the molten salt mixtures at different temperatures were comparatively investigated using immersion tests under static and dynamic states and electrochemical scans. The corrosion resistance of stainless steels and nickel‐based alloys in molten salt at 530 °C followed the sequence of 304<316L<600<825. The aggressiveness of different molten salt mixtures was compared, indicating that the ternary system was more aggressive than the binary system. The corrosion aggressiveness under dynamic state was more severe when compared to that under the static state. The N2 atmosphere was proved to be protective for alloys immersed in high temperature molten salts.