Mechanisms of molten fluoride salt corrosion of laser powder bed fused 316L stainless steels

Yanling Ge; Weiyue Zhou; Michael P. Short; Zaiqing Que

doi:10.1038/s41529-026-00830-8

Mechanisms of molten fluoride salt corrosion of laser powder bed fused 316L stainless steels

Yanling Ge
, Weiyue Zhou
, Michael P. Short
, Zaiqing Que^*

^*Corresponding author for this work

BA4509 Advanced materials for nuclear energy

MIT Massachusetts Institute of Technology

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

Abstract

Additively manufactured (AM) stainless steels (SS) are under consideration for molten salt reactors. However, molten salt corrosion of AM SS remains poorly understood. Here we present the mechanisms of corrosion of laser-based powder bed fused (LPBF) 316L SS in FLiNaK + 5 wt. % EuF3 molten salt at 650 °C. Microstructural features of dislocation cells, low-angle grain boundaries, and carbides appear to be the major underlying features influencing corrosion behavior. Corrosion-induced, salt-filled voids follow {100} crystallographic planes rather than AM-induced microstructural features. Dislocation cell structures retain Cr, and yet they appear to slow molten salt corrosion in the long run, with limited grain boundary migration observed. Larger Cr carbides disappear in the salt penetration regions, leaving only Mo carbides. Smaller carbides and remaining high Ni-enrichment layer slow down Cr depletion and molten salt penetration.

Original language	English
Journal	npj Materials degradation
DOIs	https://doi.org/10.1038/s41529-026-00830-8
Publication status	Accepted/In press - 4 Jul 2026
MoE publication type	A1 Journal article-refereed

Funding

The work is funded by VTT and MIT. YG and ZQ acknowledge the financial support from VTT Continuous renewal of excellence (GG_CORE) and Finnish SAFER2028 (National Nuclear Safety and Waste Management Research Programme 2023-2028) LOAD project (Long-term Operation on Aging and environmental Degradation of nuclear reactor materials).

Access to Document

10.1038/s41529-026-00830-8Licence: CC BY-NC-ND

Cite this

@article{6b604d29646244f389ed267b45618b8b,

title = "Mechanisms of molten fluoride salt corrosion of laser powder bed fused 316L stainless steels",

abstract = "Additively manufactured (AM) stainless steels (SS) are under consideration for molten salt reactors. However, molten salt corrosion of AM SS remains poorly understood. Here we present the mechanisms of corrosion of laser-based powder bed fused (LPBF) 316L SS in FLiNaK + 5 wt. \% EuF3 molten salt at 650 °C. Microstructural features of dislocation cells, low-angle grain boundaries, and carbides appear to be the major underlying features influencing corrosion behavior. Corrosion-induced, salt-filled voids follow \{100\} crystallographic planes rather than AM-induced microstructural features. Dislocation cell structures retain Cr, and yet they appear to slow molten salt corrosion in the long run, with limited grain boundary migration observed. Larger Cr carbides disappear in the salt penetration regions, leaving only Mo carbides. Smaller carbides and remaining high Ni-enrichment layer slow down Cr depletion and molten salt penetration.",

author = "Yanling Ge and Weiyue Zhou and Short, \{Michael P.\} and Zaiqing Que",

year = "2026",

month = jul,

day = "4",

doi = "10.1038/s41529-026-00830-8",

language = "English",

journal = "npj Materials degradation",

issn = "2397-2106",

publisher = "Springer Nature",

}

TY - JOUR

T1 - Mechanisms of molten fluoride salt corrosion of laser powder bed fused 316L stainless steels

AU - Ge, Yanling

AU - Zhou, Weiyue

AU - Short, Michael P.

AU - Que, Zaiqing

PY - 2026/7/4

Y1 - 2026/7/4

N2 - Additively manufactured (AM) stainless steels (SS) are under consideration for molten salt reactors. However, molten salt corrosion of AM SS remains poorly understood. Here we present the mechanisms of corrosion of laser-based powder bed fused (LPBF) 316L SS in FLiNaK + 5 wt. % EuF3 molten salt at 650 °C. Microstructural features of dislocation cells, low-angle grain boundaries, and carbides appear to be the major underlying features influencing corrosion behavior. Corrosion-induced, salt-filled voids follow {100} crystallographic planes rather than AM-induced microstructural features. Dislocation cell structures retain Cr, and yet they appear to slow molten salt corrosion in the long run, with limited grain boundary migration observed. Larger Cr carbides disappear in the salt penetration regions, leaving only Mo carbides. Smaller carbides and remaining high Ni-enrichment layer slow down Cr depletion and molten salt penetration.

AB - Additively manufactured (AM) stainless steels (SS) are under consideration for molten salt reactors. However, molten salt corrosion of AM SS remains poorly understood. Here we present the mechanisms of corrosion of laser-based powder bed fused (LPBF) 316L SS in FLiNaK + 5 wt. % EuF3 molten salt at 650 °C. Microstructural features of dislocation cells, low-angle grain boundaries, and carbides appear to be the major underlying features influencing corrosion behavior. Corrosion-induced, salt-filled voids follow {100} crystallographic planes rather than AM-induced microstructural features. Dislocation cell structures retain Cr, and yet they appear to slow molten salt corrosion in the long run, with limited grain boundary migration observed. Larger Cr carbides disappear in the salt penetration regions, leaving only Mo carbides. Smaller carbides and remaining high Ni-enrichment layer slow down Cr depletion and molten salt penetration.

U2 - 10.1038/s41529-026-00830-8

DO - 10.1038/s41529-026-00830-8

M3 - Article

SN - 2397-2106

JO - npj Materials degradation

JF - npj Materials degradation

ER -

Mechanisms of molten fluoride salt corrosion of laser powder bed fused 316L stainless steels

Abstract

Funding

Access to Document

Fingerprint

Cite this