On the high-temperature oxidation behavior of a niobium-bearing high nickel-chromium alloy: microstructural evolution and implications on oxidation mechanisms

• Published in: Corrosion science Vol. 220; p. 111261
• Main Authors: Shu, Shipeng, Baik, Sungil, Kazemzadeh-Atoufi, Maryam, Hu, Xiaobing, Liu, Tao, Shang, Anyu, Davis, Mark B., Kumar, Deepak, Ziebarth, Robin, Dhingra, Sandeep, Morgan, Robert D., Voorhees, Peter W., Seidman, David N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-08-2023
• Subjects: Atom-probe tomography (APT); Kinetics; Ni-Cr alloy; Oxidation; Themo-Calc; Atom-probe tomography (APT); Oxidation; Ni-Cr alloy; Kinetics; Themo-Calc
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2023.111261

The oxidation behavior of a niobium-bearing high nickel-chromium alloy, widely used in the petrochemical industry, is systematically studied at 800 °C using a combination of transmission electron microscopy and atom-probe tomography experimental techniques and thermodynamic calculations. Oxidation leads to complex surface microstructures consisting of a protective chromia layer, an amorphous SiO2 (silica) layer, Fe- and Ni-rich metallic mushroom-like austenitic protrusions/precipitates, and sub-oxide voids with highly faceted surfaces. The thermodynamic equilibrium oxides of this alloy are studied as a function of oxygen activity using Thermo-Calc and compared to the observed microstructures. The growth kinetics of oxide layers are studied in detail.
•Ni-Cr alloy oxidation behavior for protective oxide layer.•Multi-layered oxide characterization using TEM & APT.•Mechanisms of austenitic protrusions in oxide identified.•Examined thermodynamics in carbide stability, oxidation.