Extending the Passive Region of CrFeNi-Based High Entropy AlloysShow others and affiliations
2023 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 33, no 51, article id 2307897Article in journal (Refereed) Published
Abstract [en]
This study provides principles for designing new corrosion resistant high entropy alloys. The theoretical framework is a percolation model developed by Newman and Sieradzki that predicts the ability of an alloy to passivate, i.e., to form a protective surface oxide, based on its composition. Here, their model is applied to more complex materials than previously, namely amorphous CrFeNiTa and CrFeNiW alloys. Furthermore, the model describes a more complex passivation process: reforming the oxide layer above the transpassive potential of Cr. The model is used to predict the lowest concentration of Ta or W required to extend the passive region, yielding 11–14 at% Ta and 14–17 at% W. For CrFeNiTa, experiments reveal a threshold value of 13–15 at% Ta, which agrees with the prediction. For CrFeNiW, the experimentally determined threshold value is 37–45 at% W, far above the predicted value. Further investigations explore why the percolation model fails to describe the CrFeNiW system; key factors are the higher nobility and the pH sensitivity of W. These results demonstrate some limitations of the percolation model and offer complementary passivation criteria, while providing a design route for combining the properties of the 3d transition metal and refractory metal groups.
Place, publisher, year, edition, pages
John Wiley & Sons, 2023. Vol. 33, no 51, article id 2307897
Keywords [en]
corrosion, high entropy alloys, materials design, passivation, percolation theory, Cobalt alloys, Corrosion resistance, Entropy, Functional materials, High-entropy alloys, Iron alloys, Refractory metals, Tantalum alloys, Ternary alloys, Complex materials, Corrosion-resistant, Passivation process, Percolation models, Surface oxide, Theoretical framework, Threshold-value, Solvents
National Category
Materials Engineering
Identifiers
URN: urn:nbn:se:hj:diva-62497DOI: 10.1002/adfm.202307897ISI: 001062551700001Scopus ID: 2-s2.0-85170376146Local ID: HOA;;905181OAI: oai:DiVA.org:hj-62497DiVA, id: diva2:1798417
Funder
Vinnova, 2016‐05156Knowledge FoundationSwedish Research Council, 2019‐002072023-09-192023-09-192024-01-09Bibliographically approved