Optical spectroscopic and electrochemical characterization of oxide films on a ferritic stainless steel

authored by
Changfeng Fan, Jianmin Shi, Azat Sharafeev, Peter Lemmens, Klaus Dilger
Abstract

Colored oxide films that form on ferritic stainless steel in a high-temperature, oxidizing environment and correspond to different chemical compositions can cause a deterioration of pitting resistance and corrosion performance. Herein, optical spectroscopic and electrochemical techniques have been used to reveal the relationship between color, chemical composition, and corrosion resistance of oxide films formed in the temperature range from 400°C to 800°C for 30 min and at 800°C for 10, 20, 30, and 60 min. The substrate with a thin and dense passivation film leads to a low pitting potential but high corrosion resistance. Oxide films of yellowish or brownish color formed below 600°C are mainly iron oxides, which correspond to low corrosion resistance. No passivation characteristics can be observed for polarization curves of oxide films formed at 500°C and 600°C. The color of oxide films varies from blue to dark gray with the increase of oxidation time at 800°C. Corrosion resistance changes with different proportions of Fe3O4, Cr2O3, and FeCr2O4. The gray oxide films formed at 800°C for 30 min exhibit the lowest pitting susceptibility and the highest corrosion resistance.

External Organisation(s)
Technische Universität Braunschweig
Type
Article
Journal
Materials and corrosion
Volume
71
Pages
440-450
No. of pages
11
ISSN
0947-5117
Publication date
03.03.2020
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Environmental Chemistry, Mechanics of Materials, Mechanical Engineering, Surfaces, Coatings and Films, Metals and Alloys, Materials Chemistry
Electronic version(s)
https://doi.org/10.1002/maco.201911425 (Access: Open)