Title: Experimental evaluation of direct current magnetron sputtered and high-power impulse magnetron sputtered Cr coatings on SiC for light water reactor applications

Abstract

Two types of physical vapor deposition Cr coatings were deposited on chemical vapor deposited SiC coupons using conventional direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HiPIMS) to mitigate the corrosion of SiC, an advanced fuel and structural material in light water nuclear reactor cores. Coating microstructure was characterized using scanning electron microscopy and scanning transmission election microscopy. X-ray diffraction analysis was conducted for phase identification and qualitative analysis of residual stresses. The mechanical integrity of the coatings was evaluated using scratch testing, micro-indentation, and nano-indentation tests. Additionally, the microstructure of the DCMS coating consisted of fine columnar grains with nanoscale intercolumnar channels, while the HiPIMS microstructure was denser and free of any columnar defects. The DCMS coating showed a small tensile residual stress, while the HiPIMS coating was under compressive stress. Both types of coatings showed good mechanical integrity in terms of ductility and adhesion to the substrate. Corrosion performance of the coatings was assessed with a 30-day high temperature water autoclave test. Both types of coatings formed a protective Cr₂O₃ surface layer 20-30 nm thick during the autoclave test. In the DCMS coating, the columnar defects provided permeation pathways for water penetration resulting in oxide formationmore » in the intercolumnar regions in the interior of the coating. Overall, both types of Cr coatings offer promise for the mitigation of hydrothermal corrosion of SiC in light water reactor operating environments.« less

Authors:

Quillin, Kyle ^[1]; Yeom, Hwasung ^[2]; Dabney, Tyler  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-8058-8996"

McFarland, Mike  ^[3];

• Search DOE PAGES for author "McFarland, Mike"
• Search DOE PAGES for ORCID "0000-0001-7217-9765"

Sridharan, Kumar ^[4]

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+ Show Author Affiliations

1. Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering
2. Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics
3. Acree Technologies Incorporated, Concord, CA (United States)
4. Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering; Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics

Publication Date:

Thu Nov 12 00:00:00 EST 2020

Research Org.:

Univ. of Wisconsin, Madison, WI (United States)

Sponsoring Org.:

USDOE Office of Nuclear Energy (NE)

OSTI Identifier:

1850564

Alternate Identifier(s):

OSTI ID: 1776249

Grant/Contract Number:  

NE0008800

Resource Type:

Accepted Manuscript

Journal Name:

Thin Solid Films

Additional Journal Information:

Journal Volume: 716; Journal Issue: C; Journal ID: ISSN 0040-6090

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; Materials Science; Physics; Silicon carbide cladding; fuel cladding; hydrothermal corrosion; chromium coating; physical vapor deposition; high-power impulse magnetron sputtering; accident tolerant fuel