High-temperature corrosion of weld overlay coating/bulk FeCrAl exposed in O2 + H2O + KCl(s) at 600 °C – A microstructural investigation

• Published in: Journal of materials research and technology 2023-07, Vol.25, p.7008-7023
• Main Authors: Hanif, I., Ssenteza, V., Eklund, J., Nockert, J., Jonsson, T.
• Format: Article
• Language: English
• Subjects: Aluminum alloys; Bulk materials; Chlorine compounds; Chromium alloys; Coatings; Corrosion behaviour; Corrosive effects; Dilution; FeCrAl; FeCrAl alloys; High resolution transmission electron microscopy; High temperature corrosion; High temperature corrosions; Iron alloys; Materials handling equipment; Micro-structural; Microstructural investigation; Potassium compounds; Scanning electron microscopy; STEM-EDX; TEM; Ternary alloys; Weld overlay; Weld overlay coating; Welds
• ISSN: 2238-7854; 2214-0697
• DOI: 10.1016/j.jmrt.2023.07.073

This work investigates the impact of high-temperature corrosion behavior of the newly developed FeCrAl alloy Kanthal® EF101 bulk material and weld overlay coating in the presence of KCl(g)/KCl(s) at 600 °C. The oxide scale formed within the secondary corrosion regime after exposure and the impact of alloy microstructure on corrosion behavior was investigated using scanning transmission electron microscopy. The findings indicated the key microstructural differences is the alloy grain size which influences the formation of a protective scale. In addition, It is indicated that coating exhibited inferior performance than the bulk material, primarily attributed to the microstructural differences. •Corrosion behavior of Kanthal® EF101 bulk/weld overlay coating was investigated in a KCl-rich environment and the microstructure of the formed scales was characterized using STEM-EDS.•The bulk material exhibited better corrosion resistance than the overlay weld coating of the same composition.•The bulk material formed a Cr-rich layer at the metal/oxide interface, indicating protective layer.•Alloy grain size was considered to be the main factor influencing the corrosion behavior between the bulk specimen and coating.