Stainless steels are susceptible to localized forms of corrosion attack, such as pitting. The size and lifetime of a nucleated pit can vary, depending on a critical potential or current density criterion, which determines if the pit repassivates or continues growing. This work uses finite element method (FEM) modeling to compare the critical pit radii predicted by thermodynamic and kinetic repassivation criteria. Experimental electrochemical boundary conditions are used to capture the active pit kinetics. Geometric and environmental parameters, such as the pit shape and size (analogous to additively manufactured lack-of-fusion pores), solution concentration, and water layer thickness were considered to assess their impact on the pit repassivation criterion. The critical pit radius (the transition point from stable growth to repassivation) predicted for a hemispherical pit was larger when using the repassivation potential (E rp ) criteria, as opposed to the current density criteria (pit stability product). Including both the pit stability product and E rp into its calculations, the analytical maximum pit model predicted a critical radius two times more conservative than the FEA approach, under the conditions studied herein. The complex pits representing lack-of-fusion pores were shown to have minimal impact on the critical radius in atmospheric conditions.
Marshall, Rebecca S., et al. "Pit Stability Predictions of Additively Manufactured SS316 Surfaces Using Finite Element Analysis." Journal of the Electrochemical Society, vol. 169, no. 2, Feb. 2022. https://doi.org/10.1149/1945-7111/ac519d
Marshall, Rebecca S., Katona, Ryan M., Melia, Michael A., & Kelly, Robert G. (2022). Pit Stability Predictions of Additively Manufactured SS316 Surfaces Using Finite Element Analysis. Journal of the Electrochemical Society, 169(2). https://doi.org/10.1149/1945-7111/ac519d
Marshall, Rebecca S., Katona, Ryan M., Melia, Michael A., et al., "Pit Stability Predictions of Additively Manufactured SS316 Surfaces Using Finite Element Analysis," Journal of the Electrochemical Society 169, no. 2 (2022), https://doi.org/10.1149/1945-7111/ac519d
@article{osti_1846218,
author = {Marshall, Rebecca S. and Katona, Ryan M. and Melia, Michael A. and Kelly, Robert G.},
title = {Pit Stability Predictions of Additively Manufactured SS316 Surfaces Using Finite Element Analysis},
annote = { Stainless steels are susceptible to localized forms of corrosion attack, such as pitting. The size and lifetime of a nucleated pit can vary, depending on a critical potential or current density criterion, which determines if the pit repassivates or continues growing. This work uses finite element method (FEM) modeling to compare the critical pit radii predicted by thermodynamic and kinetic repassivation criteria. Experimental electrochemical boundary conditions are used to capture the active pit kinetics. Geometric and environmental parameters, such as the pit shape and size (analogous to additively manufactured lack-of-fusion pores), solution concentration, and water layer thickness were considered to assess their impact on the pit repassivation criterion. The critical pit radius (the transition point from stable growth to repassivation) predicted for a hemispherical pit was larger when using the repassivation potential (E rp ) criteria, as opposed to the current density criteria (pit stability product). Including both the pit stability product and E rp into its calculations, the analytical maximum pit model predicted a critical radius two times more conservative than the FEA approach, under the conditions studied herein. The complex pits representing lack-of-fusion pores were shown to have minimal impact on the critical radius in atmospheric conditions. },
doi = {10.1149/1945-7111/ac519d},
url = {https://www.osti.gov/biblio/1846218},
journal = {Journal of the Electrochemical Society},
issn = {ISSN 0013-4651},
number = {2},
volume = {169},
place = {United States},
publisher = {The Electrochemical Society},
year = {2022},
month = {02}}
Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences, Vol. 341, Issue 1662, p. 531-559https://doi.org/10.1098/rsta.1992.0114