High temperature corrosion behavior of 430 ferrite stainless steel in a molten sulfur environment

AISI type 430 stainless steel is a common current collector in sodium sulfur batteries. The corrosion behavior of stainless steel 430 (SS430) was investigated in this article in a sulfur environment at 350 °C using the gravimetric method. The corrosion mechanism and the characteristics of vulcanization films were studied by diffraction X-ray (XRD) and scanning electron microscopy (SEM), and resistance was tested by a four-probe tester. The results showed that the intensive vulcanization of SS430 took place at a corrosion time above 24 h. The dynamic vulcanization of SS430 first increased to a maximum point of 0.6532 mm × a -1 after 120 h in a 350 °C molten sulfur environment and then decreased. Block resistance reached 0.6058 m Ω after 120 h. The main corrosion product of SS430 was FeS 2 within 48 h and its microstructure was porous. The Cr 6 S 7 was observed again after 72 h. A dense Cr 2 S 3 and FeS 2 coating formed after 120 h, which protected the SS430 and reduced corrosion.