Microstructural characterization of oxide layers formed on Ni–20Cr–8Al alloy foam using transmission electron microscopy |
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Authors: | Hyung Giun Kim Sung Hwan Lim |
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Institution: | 1. Gangwon Regional Division, Korea Institute of Industrial Technology, Gangneung, Korea;2. Department of Advanced Materials Science and Engineering, Kangwon National University, Chuncheon, Korea |
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Abstract: | Microstructural characterization was carried out during the pre‐oxidation of Ni–20Cr–8Al alloy foam using transmission electron microscopy (TEM). During the pre‐oxidation at 1000 °C for 1, 30, and 60 min in air, the sequential formations of NiO, NiCr2O4, Cr2O3, and α‐Al2O3 1‐μm‐thick oxide layers were, respectively, characterized. Initially, during pre‐oxidization, the layers formed abnormally in an island growth mode, but they grew to be morphologically uniform after 30 min. Pores were found after only 1 min in the middle region of the oxide layers, near the Cr2O3 layer, and then these developed into critical micro‐cracks after 60 min. Copyright © 2017 John Wiley & Sons, Ltd. |
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Keywords: | NiCrAl foam oxide layers oxidation kinetics transmission electron microscopy |
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