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ZrN Phase Formation, Hardening and Nitrogen Diffusion Kinetics in Plasma Nitrided Zircaloy-4

Plasma nitridation was conducted to modify the surfaces of Zircaloy-4. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman analysis were used to characterize microstructures and phases. Surface indentation and cross-sectional indentation were performed to evaluate m...

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Autores principales: Balerio, Robert, Kim, Hyosim, Morell-Pacheco, Andres, Hawkins, Laura, Shiau, Ching-Heng, Shao, Lin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8269695/
https://www.ncbi.nlm.nih.gov/pubmed/34202338
http://dx.doi.org/10.3390/ma14133572
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author Balerio, Robert
Kim, Hyosim
Morell-Pacheco, Andres
Hawkins, Laura
Shiau, Ching-Heng
Shao, Lin
author_facet Balerio, Robert
Kim, Hyosim
Morell-Pacheco, Andres
Hawkins, Laura
Shiau, Ching-Heng
Shao, Lin
author_sort Balerio, Robert
collection PubMed
description Plasma nitridation was conducted to modify the surfaces of Zircaloy-4. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman analysis were used to characterize microstructures and phases. Surface indentation and cross-sectional indentation were performed to evaluate mechanical property changes. Nitridation forms a thin layer of ZrN phase, followed by a much deeper layer affected by nitrogen diffusion. The ZrN phase is confirmed by both TEM and Raman characterization. The Raman peaks of ZrN phase show a temperature dependence. The intensity increases with increasing nitridation temperatures, reaches a maximum at 700 °C, and then decreases at higher temperatures. The ZrN layer appears as continuous small columnar grains. The surface polycrystalline ZrN phase is harder than the bulk by a factor of ~8, and the nitrogen diffusion layer is harder by a factor of ~2–5. The activation energy of nitrogen diffusion was measured to be 2.88 eV. The thickness of the nitrogen-hardened layer is controllable by changing the nitridation temperature and duration.
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spelling pubmed-82696952021-07-10 ZrN Phase Formation, Hardening and Nitrogen Diffusion Kinetics in Plasma Nitrided Zircaloy-4 Balerio, Robert Kim, Hyosim Morell-Pacheco, Andres Hawkins, Laura Shiau, Ching-Heng Shao, Lin Materials (Basel) Article Plasma nitridation was conducted to modify the surfaces of Zircaloy-4. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman analysis were used to characterize microstructures and phases. Surface indentation and cross-sectional indentation were performed to evaluate mechanical property changes. Nitridation forms a thin layer of ZrN phase, followed by a much deeper layer affected by nitrogen diffusion. The ZrN phase is confirmed by both TEM and Raman characterization. The Raman peaks of ZrN phase show a temperature dependence. The intensity increases with increasing nitridation temperatures, reaches a maximum at 700 °C, and then decreases at higher temperatures. The ZrN layer appears as continuous small columnar grains. The surface polycrystalline ZrN phase is harder than the bulk by a factor of ~8, and the nitrogen diffusion layer is harder by a factor of ~2–5. The activation energy of nitrogen diffusion was measured to be 2.88 eV. The thickness of the nitrogen-hardened layer is controllable by changing the nitridation temperature and duration. MDPI 2021-06-25 /pmc/articles/PMC8269695/ /pubmed/34202338 http://dx.doi.org/10.3390/ma14133572 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Balerio, Robert
Kim, Hyosim
Morell-Pacheco, Andres
Hawkins, Laura
Shiau, Ching-Heng
Shao, Lin
ZrN Phase Formation, Hardening and Nitrogen Diffusion Kinetics in Plasma Nitrided Zircaloy-4
title ZrN Phase Formation, Hardening and Nitrogen Diffusion Kinetics in Plasma Nitrided Zircaloy-4
title_full ZrN Phase Formation, Hardening and Nitrogen Diffusion Kinetics in Plasma Nitrided Zircaloy-4
title_fullStr ZrN Phase Formation, Hardening and Nitrogen Diffusion Kinetics in Plasma Nitrided Zircaloy-4
title_full_unstemmed ZrN Phase Formation, Hardening and Nitrogen Diffusion Kinetics in Plasma Nitrided Zircaloy-4
title_short ZrN Phase Formation, Hardening and Nitrogen Diffusion Kinetics in Plasma Nitrided Zircaloy-4
title_sort zrn phase formation, hardening and nitrogen diffusion kinetics in plasma nitrided zircaloy-4
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8269695/
https://www.ncbi.nlm.nih.gov/pubmed/34202338
http://dx.doi.org/10.3390/ma14133572
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