Complementary Methods for the Characterization of Corrosion Products on a Plant-Exposed Superheater Tube

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• 作者：Sunday Chukwudi Okoro ; Frank Niessen…
• 关键词：Stainless steel ; (Synchrotron) X ; ray diffraction ; SEM ; High ; temperature corrosion ; Chlorination ; Spinel
• 刊名：Metallography, Microstructure, and Analysis
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：6
• 期：1
• 页码：22-35
• 全文大小：
• 刊物主题：Metallic Materials; Characterization and Evaluation of Materials; Structural Materials; Surfaces and Interfaces, Thin Films; Nanotechnology;
• 出版者：Springer US
• ISSN：2192-9270
• 卷排序：6

文摘

In this work, complex corrosion products on a superheater tube exposed to biomass firing were characterized by the complementary use of energy-dispersive synchrotron diffraction, electron microscopy, and energy-dispersive X-ray spectroscopy. Non-destructive synchrotron diffraction in transmission geometry measuring with a small gauge volume from the sample surface through the corrosion product allowed depth-resolved phase identification and revealed the presence of (Fe,Cr)₂O₃ and FeCr₂O₄. This was supplemented by microstructural and elemental analysis correlating the additional presence of a Ni-rich austenite phase to selective removal of Fe and Cr from the alloy, via a KCl-induced corrosion mechanism. Compositional variations were related to diffraction results and revealed a qualitative influence of the spinel cation concentration on the observed diffraction lines.