Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO2

Abstract Current and future power systems require chromia-forming alloys compatible with high-temperature CO2. Important questions concerning the mechanisms of oxidation and carburization remain unanswered. Herein we shed light onto these processes by studying the very initial stages of oxidation of...

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Autores principales:	Richard P. Oleksak, Rafik Addou, Bharat Gwalani, John P. Baltrus, Tao Liu, J. Trey Diulus, Arun Devaraj, Gregory S. Herman, Ömer N. Doğan
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Materials of engineering and construction. Mechanics of materials TA401-492
Acceso en línea:	https://doaj.org/article/aa0f478cc73d4c50aa8fe14ee21dd54f
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spelling	oai:doaj.org-article:aa0f478cc73d4c50aa8fe14ee21dd54f2021-12-02T14:58:42ZMolecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO210.1038/s41529-021-00194-12397-2106https://doaj.org/article/aa0f478cc73d4c50aa8fe14ee21dd54f2021-09-01T00:00:00Zhttps://doi.org/10.1038/s41529-021-00194-1https://doaj.org/toc/2397-2106Abstract Current and future power systems require chromia-forming alloys compatible with high-temperature CO2. Important questions concerning the mechanisms of oxidation and carburization remain unanswered. Herein we shed light onto these processes by studying the very initial stages of oxidation of Fe22Cr and Fe22Ni22Cr model alloys. Ambient-pressure X-ray photoelectron spectroscopy enabled in situ analysis of the oxidizing surface under 1 mbar of flowing CO2 at temperatures up to 530 °C, while postexposure analyses revealed the structure and composition of the oxidized surface at the near-atomic scale. We found that gas purity played a critical role in the kinetics of the reaction, where high purity CO2 promoted the deposition of carbon and the selective oxidation of Cr. In contrast, no carbon deposition occurred in low purity CO2 and Fe oxidation ensued, thus highlighting the critical role of impurities in defining the early oxidation pathway of the alloy. The Cr-rich oxide formed on Fe22Cr in high purity CO2 was both thicker and more permeable to carbon compared to that formed on Fe22Ni22Cr, where carbon transport appeared to occur by atomic diffusion through the oxide. Alternatively, the Fe-rich oxide formed in low purity CO2 suggested carbon transport by molecular CO2.Richard P. OleksakRafik AddouBharat GwalaniJohn P. BaltrusTao LiuJ. Trey DiulusArun DevarajGregory S. HermanÖmer N. DoğanNature PortfolioarticleMaterials of engineering and construction. Mechanics of materialsTA401-492ENnpj Materials Degradation, Vol 5, Iss 1, Pp 1-17 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Materials of engineering and construction. Mechanics of materials TA401-492
spellingShingle	Materials of engineering and construction. Mechanics of materials TA401-492 Richard P. Oleksak Rafik Addou Bharat Gwalani John P. Baltrus Tao Liu J. Trey Diulus Arun Devaraj Gregory S. Herman Ömer N. Doğan Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO2
description	Abstract Current and future power systems require chromia-forming alloys compatible with high-temperature CO2. Important questions concerning the mechanisms of oxidation and carburization remain unanswered. Herein we shed light onto these processes by studying the very initial stages of oxidation of Fe22Cr and Fe22Ni22Cr model alloys. Ambient-pressure X-ray photoelectron spectroscopy enabled in situ analysis of the oxidizing surface under 1 mbar of flowing CO2 at temperatures up to 530 °C, while postexposure analyses revealed the structure and composition of the oxidized surface at the near-atomic scale. We found that gas purity played a critical role in the kinetics of the reaction, where high purity CO2 promoted the deposition of carbon and the selective oxidation of Cr. In contrast, no carbon deposition occurred in low purity CO2 and Fe oxidation ensued, thus highlighting the critical role of impurities in defining the early oxidation pathway of the alloy. The Cr-rich oxide formed on Fe22Cr in high purity CO2 was both thicker and more permeable to carbon compared to that formed on Fe22Ni22Cr, where carbon transport appeared to occur by atomic diffusion through the oxide. Alternatively, the Fe-rich oxide formed in low purity CO2 suggested carbon transport by molecular CO2.
format	article
author	Richard P. Oleksak Rafik Addou Bharat Gwalani John P. Baltrus Tao Liu J. Trey Diulus Arun Devaraj Gregory S. Herman Ömer N. Doğan
author_facet	Richard P. Oleksak Rafik Addou Bharat Gwalani John P. Baltrus Tao Liu J. Trey Diulus Arun Devaraj Gregory S. Herman Ömer N. Doğan
author_sort	Richard P. Oleksak
title	Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO2
title_short	Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO2
title_full	Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO2
title_fullStr	Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO2
title_full_unstemmed	Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO2
title_sort	molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature co2
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/aa0f478cc73d4c50aa8fe14ee21dd54f
work_keys_str_mv	AT richardpoleksak molecularscaleinvestigationoftheoxidationbehaviorofchromiaformingalloysinhightemperatureco2 AT rafikaddou molecularscaleinvestigationoftheoxidationbehaviorofchromiaformingalloysinhightemperatureco2 AT bharatgwalani molecularscaleinvestigationoftheoxidationbehaviorofchromiaformingalloysinhightemperatureco2 AT johnpbaltrus molecularscaleinvestigationoftheoxidationbehaviorofchromiaformingalloysinhightemperatureco2 AT taoliu molecularscaleinvestigationoftheoxidationbehaviorofchromiaformingalloysinhightemperatureco2 AT jtreydiulus molecularscaleinvestigationoftheoxidationbehaviorofchromiaformingalloysinhightemperatureco2 AT arundevaraj molecularscaleinvestigationoftheoxidationbehaviorofchromiaformingalloysinhightemperatureco2 AT gregorysherman molecularscaleinvestigationoftheoxidationbehaviorofchromiaformingalloysinhightemperatureco2 AT omerndogan molecularscaleinvestigationoftheoxidationbehaviorofchromiaformingalloysinhightemperatureco2
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Molecular-scale investigation of the oxidation behavior of chromia-forming alloys in high-temperature CO2

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