Mechanical and chemical properties of PVD and cold spray Cr-coatings on Zircaloy-4

JOURNAL OF NUCLEAR MATERIALS

卷:541

Article

Umretiya, Rajnikant, V¹  Elward, Barret²  Lee, Donghwi²  Anderson, Mark²  Rebak, Raul B.³  Rojas, Jessika, V¹ 

[1] Virginia Commonwealth Univ, Dept Mech & Nucl Engn, Richmond, VA 23284 USA

[2] Univ Wisconsin, Dept Mech Engn, Madison, WI 53706 USA

[3] GE Global Res, Schenectady, NY 12309 USA

关键词: Accident tolerant fuel;    Critical heat flux;    Cr-coated Zircaloy-4;    Surface chemistry;    Wettability;    Physical vapor deposition;    Cold spray;   

DOI  :  10.1016/j.jnucmat.2020.152420

来源: Elsevier

【 摘 要 】

Accident-tolerant fuel (ATF) cladding materials aim to improve fuel reliability and safety during accident scenarios in water-cooled reactors. These ATF cladding should also perform comparable or better than the current zirconium alloy cladding under reactor normal operating conditions. Surface-modified Zircaloy-4 was produced by depositing a protective coating of chromium by two different coating techniques, Physical Vapor Deposition (PVD) and Cold Spray (CS). The coating thickness, structure, composition, and mechanical properties of the coated Zircaloy were assessed with advanced materials characterization techniques. Results showed a strengthening effect of the Cr-coating, along with similar to 83% higher hardness compared to that of the Zircaloy-4 substrate. Surface topography and surface chemistry of the Cr-coated Zircaloy-4 were assessed with contact profilometry, atomic force microscopy, contact angle goniometry, and X-ray photoelectron spectroscopy. Deposited Cr-coating significantly improved surface wettability compared to the substrate Zircaloy-4. The formation of surface oxides on the coatings by prolonged exposure to ambient air showed a further increase in the hydrophobic behavior. Surface parameters and surface chemistry after flow boiling critical heat flux tests, conducted at atmospheric pressure, evidenced a slight increase in surface roughness with notable changes in wettability associated with the formation of surface oxides. (C) 2020 Elsevier B.V. All rights reserved.

【 授权许可】

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