Electrochemical study on the hot corrosion behavior of Ni16Cr13Co4Mo alloy in molten NaCl-KCl and NaCl-KCl-Na2SO4. (15th May 2022)

• Record Type: Journal Article
• Authors: Wang, J.H.; Li, D.G.; Shao, T.M.
• Is Part Of: Corrosion science. Volume 200(2022)
• Publication Date: 2022-05-15
• Subjects: Molten salt -- Nickel-based alloy -- Electrochemical property -- Hot corrosion; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110247
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: The hot corrosion behaviors of a novel Ni16Cr13Co4Mo alloy were investigated in molten NaCl-KCl and NaCl-KCl-Na2 SO4 through electrochemical measurements, GIXRD and EPMA. The results showed that the overall corrosion was controlled by the diffusion process. Hot corrosion process was promoted by the increases in temperature and presence of Na2 SO4 . In molten NaCl-KCl, the corrosion layer was mainly composed of Cr2 O3, and exhibited p-type semiconductive properties. In molten NaCl-KCl-Na2 SO4, intergranular corrosion was observed and the corrosion layer consisted of a Cr2 O3 outer layer (p-type) and a TiO2 -Al2 O3 inner layer (n-type). The relationship between the electrochemical mechanism and hot corrosion was discussed. Highlights: The Ni16Cr13Co4Mo alloy showed different corrosion layer structures in molten NaCl-KCl and molten NaCl-KCl-Na2 SO4 . Na2 SO4 promoted the formation of corrosion products and caused intergranular corrosion. The semiconductive property of the corrosion layer changed with its composition and structure. In molten NaCl-KCl-Na2 SO4, the TiO2 -Al2 O3 inner layer had fewer defects under the protection of the Cr2 O3 outer layer.