01Dp01
有機金属分解法で作製したイットリア安定化ジルコニア被覆の作製と特性評価
Preparation and characterization of yttria-stabilized zirconia coatingby metal organic decomposition
遠藤 理帆1, 野上 修平2, 藪内 聖皓3, 菱沼 良光4, 近田 拓未1Riho Endoh , Shuhei Nogami2, Kiyohiro Yabuuchi3, Yoshimitsu Hishinuma4, Takumi Chikada1
11

静岡大学, 2東北大学, 3京都大学, 4核融合科学研究所
1
Shizuoka Univ., 2Tohoku Univ., 3Kyoto Univ., 4NIFS

1. Introduction
For the realization of a sufficient fuel cycle in afusion reactor, functional coatings have been
investigated mainly using ceramics to suppresstritium leakage through structural materials andcorrosion by liquid tritium breeders. In particular,
yttria-stabilized zirconia (YSZ) produced by theaddition of yttrium oxide (Y2O3) in zirconia oxide(ZrO2) has higher thermal stability and fracture
toughness than typical ceramics. Therefore, there
are possibilities that the YSZ coating has thermal
cycle resistance and a self-repairing function thatsuppresses crack propagation in the coating. In thisstudy, the YSZ coatings were prepared by aliquid-phase method, which has a potential forplant-scale fabrication, and the characteristics of thecoatings were investigated.
2. Experiments
Before the coating preparation, a reduced
activation
ferritic/martensitic
steel
F82H
(Fe-8Cr-2W) plate substrate was heat-treated toform a chromium oxide layer on the surface toimprove the coating performance [1]. ZrO2 coatings
doped with 4 mol% Y2O3 (4Y-YSZ) were preparedby metal organic decomposition with a dip-coating
technique. The coating procedure including dipping,drying, pre-heating, and heat treatment is describedin detail in Ref. [2]. In this study, the sample wasdipped into the coating precursor and then dried
under argon atmosphere in a glove box. The whole
coating process was repeated twice.
Four-point bending tests were performed to givethe coating damage with 1‒3 % elastic bend strainsof F82H.
Deuterium permeation tests were conducted forthe samples before and after the bending tests usinga gas-driven permeation apparatus. The deuterium
driving pressure was 10‒80 kPa, and the test
temperature was 300‒600 ºC. After the permeation
tests, thermal cycle tests were performed for thesample before the bending tests. The change indeuterium permeation flux was monitored during
ten thermal cycles by changing the sample
temperature from 300 to 600 ºC. The rates oftemperature
increase
anddecrease
wereapproximately 5 ºC/min.
3. Results and discussion
Fig. 1 shows the temperature dependence of
deuterium permeation flux for the 4Y-YSZ coating
sample before the bending tests. The permeation
flux decreased at 500 ºC due to crystallization
and/or grain growth, and the permeation barrier
performance was maintained at up to 600 ºC. In thelast measurement at 300 ºC, the permeation flux
decreased by a factor of 1700 in comparison withthat of the substrate. No significant increase in thepermeation flux observed during the thermal cycle
test. From these results, the coating might havethermal cycle resistance. In the presentation, thepermeation behavior after the bending tests will bealso discussed.

Fig. 1. Arrhenius plots of deuterium permeation flux of4Y-YSZ coating sample before bending tests.
Reference[1][2]

T. Tanaka et al., J. Nucl. Mater. 455 (2014) 630‒634
J. Mochizuki et al., Fusion Eng. Des. 136 (2018)219‒222