Abstract
The synergistic effects of Al on Cr(III) passivation in a family of (FeCoNi)100-x-yCrxAly (at.%) complex concentrated alloys (CCAs), where x = (0, 4, 10, 13, 16) and y = (0, 3, 6, 9, 13) were investigated. Homogenized solid solution alloys containing 10 at.% Cr intentionally selected below the stainless steel threshold of 12 at.% achieved excellent passivation by forming a Cr(III) rich film containing Al(III) when alloyed with small amounts of Al. For example, CCAs containing 10 at.% Cr and 6 at.% Al can attain comparable re-passivation properties as seen in 304L stainless steel in sulfuric acid. Potentiostatic re-passivation over 10 ks exposure revealed the benefit of Al addition leading to greater Cr(III) cation fractions in the film, better corrosion protection, and faster film formation. Two underlying mechanisms are proposed to explain the effect. The observed Al-Cr synergy can be understood as a type of third element effect due to Al where enrichment of Cr(III) in the passive films occurs due to the small but beneficial presence of Al(III). Al is also a secondary passivator detected in the passive film. Moreover, the potential effects of other alloying elements in CCAs were examined through the investigation of binary and ternary alloys containing Cr and Al. These studies also focused on the influence of Al additions on Cr-Cr clustering in solid solution during steady-state passivation, facilitated by chemical short-range ordering.
| Original language | English |
|---|---|
| Article number | 145523 |
| Journal | Electrochimica Acta |
| Volume | 513 |
| DOIs | |
| State | Published - Feb 10 2025 |
Funding
The authors gratefully acknowledge funding from the Office of Naval Research (ONR) through the Multidisciplinary University Research Initiative (MURI) program (Award: #N00014–20–1–2368) with program manager Dr. D. Shifler. D.S. was partially supported by the UVA-DMSE Olsen Graduate Fellowship for the duration of this work. Further, the authors acknowledge the University of Virginia Nanoscale Materials Characterization Facility for utilizing the PHI Versaprobe III XPS, Empyrean x-ray diffractometer, and Quanta SEM. PHI VersaProbe III system was supported by NSF Award #162601 - “MRI Acquisition of an X-Ray Photoelectron Spectrometer for Chemical Mapping of Evolving Surfaces: A Regional Instrument for Research and Teaching”. J.P. Couizine assisted in melting and casting the alloys. B. Redemann assisted in performing the solutionization heat treatments at the JHU PARADIM facility under the supervision of Dr. T. McQueen. Dr. E. Romanovskaia helped in reviewing an early version of the manuscript. The authors gratefully acknowledge funding from the Office of Naval Research (ONR) through the Multidisciplinary University Research Initiative (MURI) program (Award: #N00014-20-1-2368) with program manager Dr. D. Shifler. D.S. was partially supported by the UVA-DMSE Olsen Graduate Fellowship for the duration of this work. Further, the authors acknowledge the University of Virginia Nanoscale Materials Characterization Facility for utilizing the PHI Versaprobe III XPS, Empyrean x-ray diffractometer, and Quanta SEM. PHI VersaProbe III system was supported by NSF Award #162601 - “MRI Acquisition of an X-Ray Photoelectron Spectrometer for Chemical Mapping of Evolving Surfaces: A Regional Instrument for Research and Teaching”. J.P. Couizine assisted in melting and casting the alloys. B. Redemann assisted in performing the solutionization heat treatments at the JHU PARADIM facility under the supervision of Dr. T. McQueen. Dr. E. Romanovskaia helped in reviewing an early version of the manuscript.
Keywords
- Aqueous passivation
- Chemical short range ordering
- Compositionally complex alloys
- First principles
- Third element effect
- XPS