Hot corrosion of Inconel 625 wrought alloy and weld overlay on carbon steel by gas metal arc welding in 47 PbSO4-23 ZnO-13 Pb3O4-7 PbCl2-5 CdO-5 Fe2O3 molten salt mixture

Highlights: • Initial molten phases formed in the molten salt electrolyte at 515 °C. • Cr₂O₃ protective film dissolved under all the investigated temperatures. • Tendency of alloying elements to molten salt corrosion: Fe >>> Cr > Ni >>> Mo. • At 600 °C, wrought alloy 625 outperformed the weld clad for hot corrosion protection. • Anodic and cathodic reactions on polarized working electrodes were under mass-transfer control. The hot corrosion resistance of the wrought alloy 625 and the alloy 625 GMAW cladding was investigated in the molten salt mixture of 47 PbSO₄-23 ZnO-13 Pb₃O₄-7 PbCl₂-x CdO-(10-x) Fe₂O₃ [x = 5] (wt.%) at 600, 700, and 800 °C, utilizing EIS, OCP, potentiodynamic polarization, weight-loss measurement, SEM/EDX, ICP/AAS, and XRD techniques. At 600 °C, the hot corrosion resistance of the wrought alloy 625 outperformed the alloy 625 weld cladding due to the formation of a (Cr, Ni, O)-rich layer with 2.2 ± 1.3 μm in thickness. Anodic and cathodic reactions on polarized working electrodes were under mass-transfer control.