The Hot Corrosion of Metals by Molten Salts
Open accessAbstract
Some theoretical mechanisms for the hot corrosion attack of metals and alloys under thin fused salt filmsare discussed. The chemical fluxing (dissolution) of the protective oxide on a pure metal is proposed to occur wherever the gradient in the oxide solubility in the salt at the oxide/salt interface is negative, such that a reprecipitation of dissolved oxide occurs. In turn, the oxide solubility gradient is established by the nature and site of the electrochemical reduction step which always generates local basicity. The interrelation of the basicity gradient in the melt to the oxide solubility map decides the occurrence of continuing hot corrosion. In the hot corrosion of alloys, the possibility of a synergistic coupling of the dissolution for the several oxides of the components can result depending upon the specific details of the oxide solubility plots and the local basicity as established by the site of the cathodic reduction step.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The molten salt layer is a pure ionic conductor that physically separates the alloys from the gas phase.
“As with the thin aqueous layer on alloys in atmospheric corrosion, this molten salt layer is a pure ionic conductor which separates the alloys from the gas phase physically [1, 19, 47].”
From A review on molten sulfate salts induced hot corrosion (2021) · cites this paper as [47]
Hot corrosion induced by molten sulfate salts is triggered and sustained by a negative solubility gradient of protective oxide from the oxide/salt interface to the salt/gas interface.
“The hot corrosion is triggered and sustained by the negative solubility gradient of protective oxide from the oxide/salt interface to salt/gas interface.”
From A review on molten sulfate salts induced hot corrosion (2021) · cites this paper as [47]
Sulfate salts easily attach onto the surfaces of high temperature components and melt to form a thin fused salt film at elevated temperatures.
“These sulfate salts easily attach onto the surfaces of high temperature components and are melted to form a thin fused salt film at elevated temperatures.”
From A review on molten sulfate salts induced hot corrosion (2021) · cites this paper as [47]
Rapp proposed four sets of basicities at the oxide/salt interface and salt/gas interface that can provide a negative solubility gradient to sustain hot corrosion.
“According to the model shown in Fig. 4 and Eq. (25), Rapp also proposed four sets of basicities at the oxide/salt interface Ⅰ and salt/gas interface Ⅱ which could provide a negative solubility gradient to sustain the hot corrosion of the alloys (Fig. 5) [47].”
From A review on molten sulfate salts induced hot corrosion (2021) · cites this paper as [47]
Hot corrosion is sustained by the shift in equilibria of metal oxide dissolution reactions toward products according to Le Chatelier's Principle, unless the solubility of porous oxides in the molten salt reaches saturation.
“As a consequence, the hot corrosion is sustained by the shift in equilibria of Eq.(5)-(14) towards products in accordance with Le Chatelier's Principle unless the solubility of porous oxides in the molten salt reaches saturation [47].”
From A review on molten sulfate salts induced hot corrosion (2021) · cites this paper as [47]
In case B, the basicities at the two interfaces straddle the value corresponding to the minimum solubility, and the products of acidic dissolution act as reactants to promote basic dissolution, stimulating reprecipitation of porous oxides.
“Case B refers to the basicities at two interfaces that straddle the value corresponding to the minimum solubility. In this case, the products in the acidic dissolution act as reactants to promote the basic dissolution, thus stimulating the reprecipitation of porous oxides.”
From A review on molten sulfate salts induced hot corrosion (2021) · cites this paper as [47]
In cases A and C, continuous hot corrosion is induced by basic and acid dissolution when the solubility of the basic melt (case A) and acid melt (case C) at the oxide/salt interface is larger than at the salt/gas interface; if the solubility gradient is reversed, hot corrosion stops and the metal oxide layer remains intact.
“Case A and case C represent the continuous hot corrosion induced by basic and acid dissolution when the solubility of basic melt (case A) and acid melt (case C) at the oxide/salt interface is larger than that at the salt/gas interface, respectively. In contrast, hot corrosion stops and the metal oxide layer remains intact if the solubility gradient is reversed.”
From A review on molten sulfate salts induced hot corrosion (2021) · cites this paper as [47]
Cited by
Sorted by citations
Hot corrosion of materials: Fundamental studies
Rapp, R. A., & Zhang, Y.-S. (1994) · JOM · doi:10.1007/bf03222665 · Cited by 247 · see citing works
Self-citationA review on molten sulfate salts induced hot corrosion
Hu, S., Finklea, H., & Liu, X. (2021) · Journal of Materials Science & Technology · doi:10.1016/j.jmst.2021.03.013 · Cited by 183 · see citing works
Chemistry and electrochemistry of hot corrosion of metals
Rapp, R. A. (1987) · Materials Science and Engineering · doi:10.1016/0025-5416(87)90394-6 · Cited by 155 · see citing works
Self-citationRole of chlorides in hot corrosion of a cast Fe–Cr–Ni alloy. Part I: Experimental studies
Mohanty, B. P., & Shores, D. A. (2004) · Corrosion Science · doi:10.1016/j.corsci.2004.04.013 · Cited by 148 · see citing works
Effects of external stresses on hot corrosion behavior of stainless steel TP347HFG
Fu, J., Zhou, Q., Li, N., Liu, Z., & Liu, T. (2016) · Corrosion Science · doi:10.1016/j.corsci.2015.11.037 · Cited by 31 · see citing works
Kung, S. C. (2015) · Corrosion · doi:10.5006/1409 · Cited by 13 · see citing works
- Authors
- Rapp, R. A.
- Affiliations
- The Ohio State University (US)
- Corresponding author
- Rapp, Robert A.
- Venue
- ECS Proceedings Volumes
- Publisher
- The Electrochemical Society
- Published
- 1981-01
- Volume
- 1981-10
- Issue
- 1
- Pages
- 159-177
- ISSN
- 0161-6374 (ISSN-L)
- 2576-1579
- OpenAlex
- W2912910689
- Cited by
- 136
- References
- 0
- Citations by year
- 2026: 3 · 2025: 15 · 2024: 16 · 2023: 6 · 2022: 5 · 2021: 7 · 2020: 10 · 2018: 2 · 2017: 7 · 2016: 2 · 2015: 4 · 2014: 3 · 2013: 3 · 2012: 1
- FWCI
- 1.30
- Type
- journal article
- Language
- en
- Open access
- diamond
- doi.org
- Locations
- ECS Proceedings Volumes (publishedVersion)
- Funders
- National Science Foundation (7517204, 7717720)
- Division of Materials Research
- Topics
- Physical Sciences › Chemical Engineering › Fluid Flow and Transfer Processes › Molten salt chemistry and electrochemical processes
- Physical Sciences › Engineering › Aerospace Engineering › High-Temperature Coating Behaviors
- Physical Sciences › Engineering › Mechanical Engineering › Metallurgical Processes and Thermodynamics
- Keywords
- hot corrosion, molten salts, oxide dissolution, oxide solubility, electrochemical reduction, cathodic reduction, alloy corrosion, corrosion mechanism
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
