Oxidation of Nickel-Coated AISI 430 Alloy: Effect of Pre-oxidation and Fe 0.5 Ni 0.5 Inter-diffusion Layer
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Oxidation of Nickel‑Coated AISI 430 Alloy: Effect of Pre‑oxidation and Fe0.5Ni0.5 Inter‑diffusion Layer Mark K. King1 · Manoj K. Mahapatra1 Received: 13 July 2020 / Revised: 4 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract The oxidation behavior of nickel (Ni)-coated AISI 430 alloy was investigated at 800 °C in moisture-saturated (~ 3% H2O) air. Effects of pre-oxidation of AISI 430 in air and inter-diffusion layer (Fe0.5Ni0.5) of Ni-coated AISI 430, in dilute hydrogen (Ar–3%H2) at 800 °C, on the oxidation behavior were also studied. Microstructure, elemental chemistry, and compound/oxide formation across the reaction zones/oxide layer were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction techniques. Multilayered oxides/reaction zones were found for all the samples. Ni-coated AISI 430 exhibits the lowest chromium diffusion into the oxide scale from the AISI 430/oxide scale interface. Pre-oxidation of AISI 430 and inter-diffusion of Ni-coated AISI 430 show excessive chromium diffusion into the reaction zone/oxide scale and interfacial porosity.
Electronic Supplementary Material The online version of this article (https://doi.org/10.1007/s1108 5-020-09996-1) contains supplementary material, which is available to authorized users. Mark K. King and Manoj K. Mahapatra have equally contributed. * Manoj K. Mahapatra [email protected] 1
Materials Science and Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
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Oxidation of Metals
Graphic Abstract
Keywords Ni-coated AISI 430 · Pre-oxidation · P-sulfamate · Inter-diffusion · R-sulfamate · Oxidation · Microstructure
Introduction Chromia-forming ferritic alloys are preferred metallic interconnects for intermediate-temperature (650–850 °C) SOFCs and SOECs. The alloys possess their good electrical conductivity, thermal expansion match with the adjacent components, and excellent oxidation resistance for application [1, 2]. Chromia-forming ferritic alloys have two major limitations. Firstly, continual outward growth of oxide layer during service can decrease the electrical conductivity [3] and cause spallation of the oxide layer [4]. Subsequent loss of electrical contact between the interconnect and the active components (electrodes and electrolyte) degrades the system’s long-term performance [5]. Secondly, evaporation of C rO3(g) and C rO2(OH)2(g) species results in air electrode poisoning and premature degradation of cell stacks [6]. Coatings are effective to limit oxidation and evaporation of chromium species [7, 8]. A suitable coating must fulfill several requirements: (1) excellent adhesion with the metallic substrate, (2) thermal expansion coefficient similar to the substrate to minimize thermal stress, (3) oxidation and corrosion resistance, (4) prevention of chromium evaporation, and (5) high electrical conductivity. Reactive element oxides, perovskites, spinels, and metallic coatings are studied [7]. For reactive element
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