TY - JOUR
T1 - Influence of gamma-ray irradiation on mechanical property of YSZ for oxygen sensors in ADS
AU - Okubo, N.
AU - Okuno, Y.
AU - Kitamura, A.
AU - Taguchi, T.
N1 - Funding Information:
The authors are grateful to Dr N. Ishikawa of JAEA for fruitful discussion and also to Mr. Y. Uchibori and Mr. K. Nakashima of Hokkaido University for Raman spectroscopy measurements.
PY - 2018/11/15
Y1 - 2018/11/15
N2 - In the accelerator driven system, oxygen sensors, on which yttria-stabilized-zirconia (YSZ) is used for the electrolyte, will be irradiated by gamma-ray in activated lead bismuth eutectic (LBE) adopted as a both coolant and spallation target. Partially stabilized zirconia, like a 3Y-YSZ, has high strength due to the stress induced phase transformation from tetragonal (T) to monoclinic (M) phase. The mechanical properties of YSZ specimens after gamma-ray irradiation, thermal aging and immersion in LBE have been investigated in terms of the fracture surface structure. In the case of 6Y and 8Y-YSZ, the 4-point bend strength did not change even after gamma-ray irradiation and thermal aging. The 3Y-YSZ, however, showed that the strength was decreased a little by the gamma-ray irradiation, thermal aging and also immersion in LBE. The XRD results indicate that in the case of 3Y-YSZ after the annealing and soaking in LBE, the pristine surface, which is not fractured and strained by bending test, shows M phase much more than the surface of as-received one. After surface polishing of 3Y-YSZ the XRD intensity of M phase increased with increasing gamma-ray dose for the pristine surface. The bend strength of irradiated 3Y-YSZ after polishing, however, did not change in this study. These results suggest that the process of gamma-ray irradiation and thermal process around 450 °C cause pre-phase transformation from T to M, which prevents the stress induced phase transformation previously.
AB - In the accelerator driven system, oxygen sensors, on which yttria-stabilized-zirconia (YSZ) is used for the electrolyte, will be irradiated by gamma-ray in activated lead bismuth eutectic (LBE) adopted as a both coolant and spallation target. Partially stabilized zirconia, like a 3Y-YSZ, has high strength due to the stress induced phase transformation from tetragonal (T) to monoclinic (M) phase. The mechanical properties of YSZ specimens after gamma-ray irradiation, thermal aging and immersion in LBE have been investigated in terms of the fracture surface structure. In the case of 6Y and 8Y-YSZ, the 4-point bend strength did not change even after gamma-ray irradiation and thermal aging. The 3Y-YSZ, however, showed that the strength was decreased a little by the gamma-ray irradiation, thermal aging and also immersion in LBE. The XRD results indicate that in the case of 3Y-YSZ after the annealing and soaking in LBE, the pristine surface, which is not fractured and strained by bending test, shows M phase much more than the surface of as-received one. After surface polishing of 3Y-YSZ the XRD intensity of M phase increased with increasing gamma-ray dose for the pristine surface. The bend strength of irradiated 3Y-YSZ after polishing, however, did not change in this study. These results suggest that the process of gamma-ray irradiation and thermal process around 450 °C cause pre-phase transformation from T to M, which prevents the stress induced phase transformation previously.
KW - ADS
KW - Gamma-ray irradiation
KW - Oxygen sensor
KW - Phase transformation
KW - YSZ
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U2 - 10.1016/j.nimb.2017.10.021
DO - 10.1016/j.nimb.2017.10.021
M3 - Article
AN - SCOPUS:85035060413
VL - 435
SP - 198
EP - 202
JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
SN - 0168-583X
ER -