SYMPOSIA PAPER Published: 30 January 2015
STP154320120161

Application of Coating Technology on Zirconium-Based Alloy to Decrease High-Temperature Oxidation

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Since the Fukushima accident, it has been recognized that a hydrogen-related explosion is one of the major concerns regarding reactor safety during the high-temperature oxidation of zirconium alloys. To decrease the high-temperature oxidation rate of zirconium-based alloy, a coating technology for the zirconium alloy surface was considered. The selection of coating materials was based on the neutron cross-section, thermal conductivity, thermal expansion, melting point, phase transformation behavior, and high-temperature oxidation rate. After consideration of these factors, silicon was selected as a coating material for the first surface coating of zirconium-based alloy. A plasma spray and laser beam scanning were selected for the coating method, as both can be applied to a long tube shape without high-vacuum and high-temperature environments during the coating process. After Si-coated samples on Zircaloy-4 sheet had been prepared via plasma spray and combined plasma spray–laser beam scanning treatments, the samples were tested in a high-temperature steam environment at 1200°C for 2000 s. The adhesion property of the Si-coated layer prepared via plasma spray was insufficient for the high-temperature application, whereas the stability of the Si-coated layer prepared with both plasma spray and laser beam scanning treatments was maintained without peeling after a high-temperature oxidation test. A very thin oxide layer, which was a few micrometers in thickness, was formed on the Si-coated surface, whereas a ZrO2 layer 110 μm in thickness was observed on the Zircaloy-4 surface. From this result, it was determined that the Si-coated layer successfully acted as corrosion barrier layer to resist the high-temperature oxidation of zirconium-based alloy.

Author Information

Kim, Hyun-Gil
LWR Fuel Technology Division, KAERI, Yuseong-gu, Daejeon, KR
Kim, Il-Hyun
LWR Fuel Technology Division, KAERI, Yuseong-gu, Daejeon, KR
Park, Jeong-Yong
LWR Fuel Technology Division, KAERI, Yuseong-gu, Daejeon, KR
Koo, Yang-Hyun
LWR Fuel Technology Division, KAERI, Yuseong-gu, Daejeon, KR
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Details
Developed by Committee: B10
Pages: 1–24
DOI: 10.1520/STP154320120161
ISBN-EB: 978-0-8031-7580-8
ISBN-13: 978-0-8031-7529-7