Corrosion behavior of alloy 625 in PbSO4-Pb3O4-PbCl2- ZnO-10 Wt pct CdO molten salt medium

E. Mohammadi Zahrani, A. M. Alfantazi

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Corrosion behavior and degradation mechanisms of alloy 625 under a 47.288 PbSO4-12.776 Pb3O4-6.844PbCl2-23.108ZnO-10CdO (wt pct) molten salt mixture under air atmosphere were studied at 873 K, 973 K, and 1073 K (60°C, 70°C, and 80°C). Electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) measurements, and potentiodynamic polarization techniques were used to evaluate the degradation mechanisms and characterize the corrosion behavior of the alloy. Morphology, chemical composition, and phase structure of the corrosion products and surface layers of the corroded specimens were studied by scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and X-ray map analyses. Results confirmed that during the exposure of alloy 625 to the molten salt, chromium was mainly dissolved through an active oxidation process as CrO3, Cr2O3, and CrNbO4, while nickel dissolved only as NiO in the system. Formation of a porous and nonprotective oxide layer with low resistance is responsible for the weak protective properties of the barrier layer at high temperatures of 973 K and 1073 K (70°C and 80°C). There were two kinds of attack for INCONEL 625, including general surface corrosion and pitting. Pitting corrosion occurred due to the breakdown of the initial oxide layer by molten salt dissolution of the oxide or oxide cracking.

Original languageBritish English
Pages (from-to)2857-2868
Number of pages12
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Issue number8
StatePublished - Aug 2012


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