Factors governing passivation behavior of Fe-Cr-Al-Ti alloys in sulfate containing acidified solutions: Uncovering the many roles of Ti

Debashish Sur; Samuel B. Inman; Kaitlyn L. Anderson; Nathan C. Smith; Matthew S. Barbieri; Jie Qi; Christopher M. Wolverton; John R. Scully

doi:10.1016/j.mtla.2025.102370

Factors governing passivation behavior of Fe-Cr-Al-Ti alloys in sulfate containing acidified solutions: Uncovering the many roles of Ti

Debashish Sur
, Samuel B. Inman
, Kaitlyn L. Anderson
, Nathan C. Smith
, Matthew S. Barbieri
, Jie Qi
, Christopher M. Wolverton
, John R. Scully

Corrosion Science & Technology

Research output: Contribution to journal › Article › peer-review

12 Scopus citations

Abstract

Passivation induced corrosion resistance of non-equiatomic BCC Fe-Cr-Al-Ti alloys, including critical passivator concentration, the roles of each alloying element, and possible synergies between the passivating components, i.e., Ti, Cr, and Al are presented. Two solid-solution BCC alloy series: Fe-8Cr-8Al-xTi and Fe-xCr-{16-x}Al-8Ti, where x was varied from 0 to 16 at.%, were investigated in acidified 0.1 M Na₂SO_4(aq) solutions. Short- and long-term passivation behaviors and oxide passive film chemistry were characterized. Alloys with at least 4 at.% Ti with 8 at.% both Cr and Al; or 8 at.% Ti with a Cr/Al ratio higher than 0.5 exhibited excellent corrosion resistance in pH 1 solution having a lower currrent density than 304L stainless steel. Ti additions to Fe-Cr-Al alloys were predicted to not only function as a passivating species but also to act as a species that alters the chemical short-range order by clustering of Cr-Cr pairs in their 1^st nearest neighbors’ arrangement. This could be forecast using a “Coherent Ordering Descriptor” based on Monte Carlo simulations supported by first-principles Density Functional Theory calculations. The possibility of a new Ti containing highly corrosion-resistant low-cost stainless steel with only 4 at.% Ti and 8 at.% Cr while using 88 at.% inexpensive Fe and Al is suggested. Two underlying mechanisms describing the enhanced passivation behaviors are discussed based on the chemical short-range ordering of Cr atoms, and passive film stability provided by mixed oxide species, suggesting concepts useful for designing new lightweight corrosion-resistant alloys.

Original language	English
Article number	102370
Journal	Materialia
Volume	39
DOIs	https://doi.org/10.1016/j.mtla.2025.102370
State	Published - Mar 2025

Funding

The authors acknowledge the partial funding provided by the Office of Naval Research (ONR) through its grants N00014-19-1-2420 , N00014-20-1-2368 , and N00014-23-1-2441 , all of which are managed by program manager Dr. D. Shifler. Further, the authors acknowledge the contributions of Dr. E.J. Opila and Dr. C. Luckhardt for providing the furnaces required for performing the solutionizing heat treatments. Dr. S. J. Poon at the UVA Department of Physics for providing the facilities for arc melting and ingot recasting. Dr H. Heinrich of UVA's Nanoscale Materials Characterization Facility (NMCF) for TEM-EDS and diffraction measurements. The authors acknowledge for the utilization of XRD, SEM-EDS, TEM, and the XPS within UVA's Nanoscale Materials Characterization Facility (NMCF) and acknowledge NSF MRI award #1626201 for the acquisition of XPS instrument. D. Sur expresses his gratitude to the UVA SEAS Co-Teaching Fellowship for partial financial support.

Keywords

Aqueous corrosion
Chemical short range ordering
DFT
EIS
Monte Carlo
Third element effect
Titanium
XPS
XRD

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10.1016/j.mtla.2025.102370

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@article{9c242cc14bf04d0f99a8f2c1e058993a,

title = "Factors governing passivation behavior of Fe-Cr-Al-Ti alloys in sulfate containing acidified solutions: Uncovering the many roles of Ti",

abstract = "Passivation induced corrosion resistance of non-equiatomic BCC Fe-Cr-Al-Ti alloys, including critical passivator concentration, the roles of each alloying element, and possible synergies between the passivating components, i.e., Ti, Cr, and Al are presented. Two solid-solution BCC alloy series: Fe-8Cr-8Al-xTi and Fe-xCr-\{16-x\}Al-8Ti, where x was varied from 0 to 16 at.\%, were investigated in acidified 0.1 M Na2SO4(aq) solutions. Short- and long-term passivation behaviors and oxide passive film chemistry were characterized. Alloys with at least 4 at.\% Ti with 8 at.\% both Cr and Al; or 8 at.\% Ti with a Cr/Al ratio higher than 0.5 exhibited excellent corrosion resistance in pH 1 solution having a lower currrent density than 304L stainless steel. Ti additions to Fe-Cr-Al alloys were predicted to not only function as a passivating species but also to act as a species that alters the chemical short-range order by clustering of Cr-Cr pairs in their 1st nearest neighbors{\textquoteright} arrangement. This could be forecast using a {\textquotedblleft}Coherent Ordering Descriptor{\textquotedblright} based on Monte Carlo simulations supported by first-principles Density Functional Theory calculations. The possibility of a new Ti containing highly corrosion-resistant low-cost stainless steel with only 4 at.\% Ti and 8 at.\% Cr while using 88 at.\% inexpensive Fe and Al is suggested. Two underlying mechanisms describing the enhanced passivation behaviors are discussed based on the chemical short-range ordering of Cr atoms, and passive film stability provided by mixed oxide species, suggesting concepts useful for designing new lightweight corrosion-resistant alloys.",

keywords = "Aqueous corrosion, Chemical short range ordering, DFT, EIS, Monte Carlo, Third element effect, Titanium, XPS, XRD",

author = "Debashish Sur and Inman, \{Samuel B.\} and Anderson, \{Kaitlyn L.\} and Smith, \{Nathan C.\} and Barbieri, \{Matthew S.\} and Jie Qi and Wolverton, \{Christopher M.\} and Scully, \{John R.\}",

note = "Publisher Copyright: {\textcopyright} 2025 Acta Materialia Inc.",

year = "2025",

month = mar,

doi = "10.1016/j.mtla.2025.102370",

language = "English",

volume = "39",

journal = "Materialia",

issn = "2589-1529",

publisher = "Elsevier",

}

TY - JOUR

T1 - Factors governing passivation behavior of Fe-Cr-Al-Ti alloys in sulfate containing acidified solutions

T2 - Uncovering the many roles of Ti

AU - Sur, Debashish

AU - Inman, Samuel B.

AU - Anderson, Kaitlyn L.

AU - Smith, Nathan C.

AU - Barbieri, Matthew S.

AU - Qi, Jie

AU - Wolverton, Christopher M.

AU - Scully, John R.

PY - 2025/3

Y1 - 2025/3

N2 - Passivation induced corrosion resistance of non-equiatomic BCC Fe-Cr-Al-Ti alloys, including critical passivator concentration, the roles of each alloying element, and possible synergies between the passivating components, i.e., Ti, Cr, and Al are presented. Two solid-solution BCC alloy series: Fe-8Cr-8Al-xTi and Fe-xCr-{16-x}Al-8Ti, where x was varied from 0 to 16 at.%, were investigated in acidified 0.1 M Na2SO4(aq) solutions. Short- and long-term passivation behaviors and oxide passive film chemistry were characterized. Alloys with at least 4 at.% Ti with 8 at.% both Cr and Al; or 8 at.% Ti with a Cr/Al ratio higher than 0.5 exhibited excellent corrosion resistance in pH 1 solution having a lower currrent density than 304L stainless steel. Ti additions to Fe-Cr-Al alloys were predicted to not only function as a passivating species but also to act as a species that alters the chemical short-range order by clustering of Cr-Cr pairs in their 1st nearest neighbors’ arrangement. This could be forecast using a “Coherent Ordering Descriptor” based on Monte Carlo simulations supported by first-principles Density Functional Theory calculations. The possibility of a new Ti containing highly corrosion-resistant low-cost stainless steel with only 4 at.% Ti and 8 at.% Cr while using 88 at.% inexpensive Fe and Al is suggested. Two underlying mechanisms describing the enhanced passivation behaviors are discussed based on the chemical short-range ordering of Cr atoms, and passive film stability provided by mixed oxide species, suggesting concepts useful for designing new lightweight corrosion-resistant alloys.

AB - Passivation induced corrosion resistance of non-equiatomic BCC Fe-Cr-Al-Ti alloys, including critical passivator concentration, the roles of each alloying element, and possible synergies between the passivating components, i.e., Ti, Cr, and Al are presented. Two solid-solution BCC alloy series: Fe-8Cr-8Al-xTi and Fe-xCr-{16-x}Al-8Ti, where x was varied from 0 to 16 at.%, were investigated in acidified 0.1 M Na2SO4(aq) solutions. Short- and long-term passivation behaviors and oxide passive film chemistry were characterized. Alloys with at least 4 at.% Ti with 8 at.% both Cr and Al; or 8 at.% Ti with a Cr/Al ratio higher than 0.5 exhibited excellent corrosion resistance in pH 1 solution having a lower currrent density than 304L stainless steel. Ti additions to Fe-Cr-Al alloys were predicted to not only function as a passivating species but also to act as a species that alters the chemical short-range order by clustering of Cr-Cr pairs in their 1st nearest neighbors’ arrangement. This could be forecast using a “Coherent Ordering Descriptor” based on Monte Carlo simulations supported by first-principles Density Functional Theory calculations. The possibility of a new Ti containing highly corrosion-resistant low-cost stainless steel with only 4 at.% Ti and 8 at.% Cr while using 88 at.% inexpensive Fe and Al is suggested. Two underlying mechanisms describing the enhanced passivation behaviors are discussed based on the chemical short-range ordering of Cr atoms, and passive film stability provided by mixed oxide species, suggesting concepts useful for designing new lightweight corrosion-resistant alloys.

KW - Aqueous corrosion

KW - Chemical short range ordering

KW - DFT

KW - EIS

KW - Monte Carlo

KW - Third element effect

KW - Titanium

KW - XPS

KW - XRD

UR - https://www.scopus.com/pages/publications/85217897888

U2 - 10.1016/j.mtla.2025.102370

DO - 10.1016/j.mtla.2025.102370

M3 - Article

AN - SCOPUS:85217897888

SN - 2589-1529

VL - 39

JO - Materialia

JF - Materialia

M1 - 102370

ER -

Factors governing passivation behavior of Fe-Cr-Al-Ti alloys in sulfate containing acidified solutions: Uncovering the many roles of Ti

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