Investigating the transport mechanisms governing the oxidation of Hastelloy BC-1 by in situ ToF-SIMS

• Published in: Corrosion science Vol. 159; p. 108138
• Main Authors: Henderson, Jeffrey D., Seyeux, Antoine, Zanna, Sandrine, Biesinger, Mark C., Shoesmith, David W., Noël, James J., Marcus, Philippe
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.10.2019; Elsevier BV
• Subjects: Chromium; Hastelloy (trademark); Hastelloy BC-1; High temperature; In situ; Ions; Isotopic labelling; Molybdenum; Oxidation; Photoelectrons; Secondary ion mass spectrometry; Solid-state ion transport; Superalloy; Time of flight photoelectron coincidence spectroscopy; ToF-SIMS; Transport; XPS; Superalloy; ToF-SIMS; In situ; Oxidation; Isotopic labelling; XPS; Hastelloy BC-1; Solid-state ion transport
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2019.108138

•The air-formed oxide on Hastelloy BC-1 contained Cr- and Mo- rich regions in the inner and outer oxide, respectively.•Empirical evidence shows O atom incorporation at the outer interfaces of both the Cr- and Mo-rich regions of the oxide.•Heating the air-formed oxide to 300 °C did not increase its thickness, but, further heating to 500 °C led to the thickening.•In all cases, temperature increases induced structural modification to the oxides which then reverted during oxidation. This paper presents insight into the structure and transport mechanisms involved in the surface oxidation of Hastelloy BC-1, gained by means of in situ time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy. The native, air-formed oxide, comprising Cr-rich (inner) and Mo-rich (outer) layers, was found to be on the order of 1–2 nm thick. Oxide thickness did not change when the temperature was increased to 300 °C in oxygen atmosphere but increased to ˜10 nm after exposure at 500 °C. The mechanisms of oxide growth/maintenance as well as observations on the effect of elevated temperatures on oxide structure are discussed.