Location of cobalt impurities in the surface oxide of stainless steel 316L and metal release in synthetic biological fluids

Authors

Xuying Wang
Jonas Hedberg
Heng-Yong Nie
Mark Biesinger, Surface Science Western and Dept. of ChemistryFollow
Inger Odnevall
Yolanda S. Hedberg, Western UniversityFollow

Document Type

Article

Publication Date

3-7-2022

Journal

Materials & Design

Volume

215

Issue

110524

URL with Digital Object Identifier

https://doi.org/10.1016/j.matdes.2022.110524

Abstract

Since 2021, cobalt (Co) is in Europe classified as carcinogen in quantities exceeding 0.1 wt-%. This affects nickel-rich stainless steels, which contain about 0.2 wt-% Co impurities. Previous findings show the bioaccessibility of Co in stainless steel to be primarily determined by the corrosion resistance. It has been unclear whether Co is distributed heterogeneously in the alloy and the outermost surface and whether a specific location would pose a risk for Co release under specific exposure conditions. This study aimed at locating Co in stainless steel 316L (0.2 wt-% Co) surfaces prior to and after exposure to different synthetic body fluids for 24 h at 37 °C. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry (ICPMS) investigated the location of Co in the surface oxide and extent of release along with other metals (iron, chromium, nickel, and manganese) into synthetic biological fluids (gastric fluid, pH 1.5; lysosomal fluid, pH 4.5; phosphate buffered saline-PBS, pH 7.4). Co was homogeneously distributed along with metallic nickel beneath the surface oxide and co-released with other metals upon surface reformation and passivation. Exposure in PBS resulted in the incorporation of both Co and phosphate in the oxide.

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This work is licensed under a Creative Commons Attribution 4.0 License.

Citation of this paper:

Xuying Wang, Jonas Hedberg, Heng-Yong Nie, Mark C. Biesinger, Inger Odnevall, Yolanda S. Hedberg, Location of cobalt impurities in the surface oxide of stainless steel 316L and metal release in synthetic biological fluids, Materials & Design, Volume 215, 2022, 110524, ISSN 0264-1275, https://doi.org/10.1016/j.matdes.2022.110524. (https://www.sciencedirect.com/science/article/pii/S0264127522001459)