Effect of Si Content on the Mechanical Behavior, Corrosion Resistance, and Passive Film Characteristics of Fe–Co–Ni–Cr–Si Medium-Entropy Alloys
Abstract
1. Introduction
2. Materials and Methods
3. Results and Discussions
3.1. Analysis of Phase
3.2. Microstructure
3.3. Mechanical Properties
3.4. Corrosion Resistance
3.5. Corrosion Morphology
4. Conclusions
- (1)
- Microstructural characterization indicates that all Si-containing MEAs exhibit a dual-phase microstructure composed of FCC and BCC phases. Increasing Si content increases the volume fraction of the BCC phase and correspondingly decreases that of the FCC phase.
- (2)
- Both hardness and yield strength increase with Si content. Yield strength shows an approximately linear dependence on Si concentration. The strengthening is primarily attributed to Si-induced solid solution strengthening.
- (3)
- Electrochemical measurements in 3.5 wt.% NaCl indicate that the MEA with the highest Si content (Si6) has the best corrosion resistance among the compositions studied. Localized pitting was identified as the dominant corrosion mechanism.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Conflicts of Interest
References
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Alloy | Icorr Corrosion Potential, A/cm2 | Ecorr Current Density, V | Corrosion Rate, μm/year |
---|---|---|---|
Si2 | (1.21 ± 0.02) × 10−6 | −0.480 ± 0.05 | ~14.1 ± 0.10 |
Si4 | (0.709 ± 0.03) × 10−6 | −0.371 ± 0.02 | ~8.07 ± 0.27 |
Si6 | (0.401 + 0.19)× 10−6 | −0.650 ± 0.03 | ~4.65 ± 0.19 |
Alloy | Rs, Ω⋅cm2 | Rf, Ω⋅cm2 | CPEf, 10−6⋅Ω–1⋅sn⋅cm–2 | n1 | Cf, µF/cm2 | Rct, 105⋅Ω⋅cm2 | CPEdl, 10−6⋅Ω–1⋅sn⋅cm−2 | n2 | Cdl, µF/cm | dfilm, nm | ddl, nm | dtotal, nm |
---|---|---|---|---|---|---|---|---|---|---|---|---|
Si2 | 13.4 | 5.55 | 4.97 | 0.963 | 3.43 | 3.93 | 23.2 × 10−6 | 0.871 | 7.01 | 6.20 | 3.02 | 9.22 |
Si4 | 12.9 | 6.31 | 4.48 | 0.908 | 1.67 | 2.66 | 8.7 × 10−6 | 0.876 | 12.49 | 12.72 | 8.85 | 21.67 |
Si6 | 13.2 | 8.98 | 13.6 | 0.908 | 5.68 | 7.05 | 18.6 × 10−6 | 0.894 | 4.65 | 3.74 | 3.06 | 6.80 |
Alloy | Region | Fe (at%) | Co (at%) | Cr (at%) | Ni (at%) | Si (at%) | O2− (at%) |
---|---|---|---|---|---|---|---|
Si2 | corroded | 62.58 | 9.98 | 17.13 | 8.30 | 1.38 | 0.63 |
non-corroded | 60.10 | 9.54 | 16.67 | 7.02 | 2.31 | 4.36 | |
Si4 | corroded | 62.81 | 9.03 | 16.44 | 8.00 | 3.73 | – |
non-corroded | 61.42 | 9.01 | 16.53 | 7.02 | 4.11 | 1.91 | |
Si6 | corroded | 64.16 | 7.74 | 17.31 | 6.54 | 4.25 | – |
non-corroded | 63.59 | 7.64 | 16.05 | 6.61 | 6.09 | – |
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Yang, S.; Wei, R.; Wei, X.; Cao, J.; Ren, J. Effect of Si Content on the Mechanical Behavior, Corrosion Resistance, and Passive Film Characteristics of Fe–Co–Ni–Cr–Si Medium-Entropy Alloys. Coatings 2025, 15, 1137. https://doi.org/10.3390/coatings15101137
Yang S, Wei R, Wei X, Cao J, Ren J. Effect of Si Content on the Mechanical Behavior, Corrosion Resistance, and Passive Film Characteristics of Fe–Co–Ni–Cr–Si Medium-Entropy Alloys. Coatings. 2025; 15(10):1137. https://doi.org/10.3390/coatings15101137
Chicago/Turabian StyleYang, Sen, Ran Wei, Xin Wei, Jiayi Cao, and Jiepeng Ren. 2025. "Effect of Si Content on the Mechanical Behavior, Corrosion Resistance, and Passive Film Characteristics of Fe–Co–Ni–Cr–Si Medium-Entropy Alloys" Coatings 15, no. 10: 1137. https://doi.org/10.3390/coatings15101137
APA StyleYang, S., Wei, R., Wei, X., Cao, J., & Ren, J. (2025). Effect of Si Content on the Mechanical Behavior, Corrosion Resistance, and Passive Film Characteristics of Fe–Co–Ni–Cr–Si Medium-Entropy Alloys. Coatings, 15(10), 1137. https://doi.org/10.3390/coatings15101137