TEM/STEM study of Zircaloy-2 with protective FeAl(Cr) layers under simulated BWR environment and high-temperature steam exposure

Donghee Park; Peter A. Mouche; Weicheng Zhong; Kiran K. Mandapaka; Gary S. Was; Brent J. Heuser

doi:10.1016/j.jnucmat.2018.01.055

TEM/STEM study of Zircaloy-2 with protective FeAl(Cr) layers under simulated BWR environment and high-temperature steam exposure

Donghee Park, Peter A. Mouche, Weicheng Zhong, Kiran K. Mandapaka, Gary S. Was, Brent J. Heuser

Research output: Contribution to journal › Article › peer-review

17 Scopus citations

Abstract

FeAl(Cr) thin-film depositions on Zircaloy-2 were studied using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) with respect to oxidation behavior under simulated boiling water reactor (BWR) conditions and high-temperature steam. Columnar grains of FeAl with Cr in solid solution were formed on Zircaloy-2 coupons using magnetron sputtering. NiFe₂O₄ precipitates on the surface of the FeAl(Cr) coatings were observed after the sample was exposed to the simulated BWR environment. High-temperature steam exposure resulted in grain growth and consumption of the FeAl(Cr) layer, but no delamination at the interface. Outward Al diffusion from the FeAl(Cr) layer occurred during high-temperature steam exposure (700 °C for 3.6 h) to form a 100-nm-thick alumina oxide layer, which was effective in mitigating oxidation of the Zircaloy-2 coupons. Zr intermetallic precipitates formed near the FeAl(Cr) layer due to the inward diffusion of Fe and Al. The counterflow of vacancies in response to the Al and Fe diffusion led to porosity within the FeAl(Cr) layer.

Original language	English
Pages (from-to)	95-105
Number of pages	11
Journal	Journal of Nuclear Materials
Volume	502
DOIs	https://doi.org/10.1016/j.jnucmat.2018.01.055
State	Published - Apr 15 2018
Externally published	Yes

Funding

This work was performed with support from the US Department of Energy Nuclear Energy University Programs Integrated Research Project under contract number IRP-12-4728 ( DE-00131989 ). In addition, this work was carried out in part in the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois, which are partially supported by the US Department of Energy under Grants DE-FG02-07ER46453 and DE-FG02-07ER46471 .

Funders	Funder number
US Department of Energy Nuclear Energy University Programs Integrated Research Project	IRP-12-4728, DE-00131989
U.S. Department of Energy	DE-FG02-07ER46453, DE-FG02-07ER46471

Keywords

Corrosion
FeCrAl
LWR cladding
Oxidation
Protective coatings
TEM

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10.1016/j.jnucmat.2018.01.055

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title = "TEM/STEM study of Zircaloy-2 with protective FeAl(Cr) layers under simulated BWR environment and high-temperature steam exposure",

abstract = "FeAl(Cr) thin-film depositions on Zircaloy-2 were studied using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) with respect to oxidation behavior under simulated boiling water reactor (BWR) conditions and high-temperature steam. Columnar grains of FeAl with Cr in solid solution were formed on Zircaloy-2 coupons using magnetron sputtering. NiFe2O4 precipitates on the surface of the FeAl(Cr) coatings were observed after the sample was exposed to the simulated BWR environment. High-temperature steam exposure resulted in grain growth and consumption of the FeAl(Cr) layer, but no delamination at the interface. Outward Al diffusion from the FeAl(Cr) layer occurred during high-temperature steam exposure (700 °C for 3.6 h) to form a 100-nm-thick alumina oxide layer, which was effective in mitigating oxidation of the Zircaloy-2 coupons. Zr intermetallic precipitates formed near the FeAl(Cr) layer due to the inward diffusion of Fe and Al. The counterflow of vacancies in response to the Al and Fe diffusion led to porosity within the FeAl(Cr) layer.",

keywords = "Corrosion, FeCrAl, LWR cladding, Oxidation, Protective coatings, TEM",

author = "Donghee Park and Mouche, {Peter A.} and Weicheng Zhong and Mandapaka, {Kiran K.} and Was, {Gary S.} and Heuser, {Brent J.}",

note = "Publisher Copyright: {\textcopyright} 2018 Elsevier B.V.",

year = "2018",

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doi = "10.1016/j.jnucmat.2018.01.055",

language = "English",

volume = "502",

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T1 - TEM/STEM study of Zircaloy-2 with protective FeAl(Cr) layers under simulated BWR environment and high-temperature steam exposure

AU - Park, Donghee

AU - Mouche, Peter A.

AU - Zhong, Weicheng

AU - Mandapaka, Kiran K.

AU - Was, Gary S.

AU - Heuser, Brent J.

PY - 2018/4/15

Y1 - 2018/4/15

N2 - FeAl(Cr) thin-film depositions on Zircaloy-2 were studied using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) with respect to oxidation behavior under simulated boiling water reactor (BWR) conditions and high-temperature steam. Columnar grains of FeAl with Cr in solid solution were formed on Zircaloy-2 coupons using magnetron sputtering. NiFe2O4 precipitates on the surface of the FeAl(Cr) coatings were observed after the sample was exposed to the simulated BWR environment. High-temperature steam exposure resulted in grain growth and consumption of the FeAl(Cr) layer, but no delamination at the interface. Outward Al diffusion from the FeAl(Cr) layer occurred during high-temperature steam exposure (700 °C for 3.6 h) to form a 100-nm-thick alumina oxide layer, which was effective in mitigating oxidation of the Zircaloy-2 coupons. Zr intermetallic precipitates formed near the FeAl(Cr) layer due to the inward diffusion of Fe and Al. The counterflow of vacancies in response to the Al and Fe diffusion led to porosity within the FeAl(Cr) layer.

AB - FeAl(Cr) thin-film depositions on Zircaloy-2 were studied using transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) with respect to oxidation behavior under simulated boiling water reactor (BWR) conditions and high-temperature steam. Columnar grains of FeAl with Cr in solid solution were formed on Zircaloy-2 coupons using magnetron sputtering. NiFe2O4 precipitates on the surface of the FeAl(Cr) coatings were observed after the sample was exposed to the simulated BWR environment. High-temperature steam exposure resulted in grain growth and consumption of the FeAl(Cr) layer, but no delamination at the interface. Outward Al diffusion from the FeAl(Cr) layer occurred during high-temperature steam exposure (700 °C for 3.6 h) to form a 100-nm-thick alumina oxide layer, which was effective in mitigating oxidation of the Zircaloy-2 coupons. Zr intermetallic precipitates formed near the FeAl(Cr) layer due to the inward diffusion of Fe and Al. The counterflow of vacancies in response to the Al and Fe diffusion led to porosity within the FeAl(Cr) layer.

KW - Corrosion

KW - FeCrAl

KW - LWR cladding

KW - Oxidation

KW - Protective coatings

KW - TEM

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DO - 10.1016/j.jnucmat.2018.01.055

M3 - Article

AN - SCOPUS:85041895173

SN - 0022-3115

VL - 502

SP - 95

EP - 105

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

ER -

TEM/STEM study of Zircaloy-2 with protective FeAl(Cr) layers under simulated BWR environment and high-temperature steam exposure

Abstract

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Keywords

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