Corrosion behavior of Ni–25Cr–10Fe–3Si–xMo alloys beneath KCl–ZnCl2 deposits at 650°C: Role of long-term aging

The corrosion behavior of unaged and thermally aged Ni–25Cr–10Fe–3Si–xMo (x = 0, 3 wt%) alloys was studied beneath KCl–ZnCl₂ deposits at 650°C. The results indicated that the addition of Mo promoted the formation of a continuous Si-rich protective layer and improved the corrosion performance of the unaged Ni–25Cr–10Fe–3Si–xMo alloys. The precipitates formed after long-term aging greatly affect the corrosion resistance of the thermally aged alloys. The M₂₃C₆ along the grain boundaries is beneficial to improve corrosion resistance, however, the dispersed Laves phase and Sigma deteriorate corrosion resistance.