TY - JOUR
T1 - Mechanical properties and microstructure of Yb2SiO5 environmental barrier coatings under isothermal heat treatment
AU - Jang, Byung Koog
AU - Nagashima, Nobuo
AU - Kim, Seongwon
AU - Oh, Yoon Suk
AU - Lee, Sung Min
AU - Kim, Hyung Tae
N1 - Funding Information:
This work was supported KAKENHI (Grant Number; 19K05016 ) of Japan Society for the Promotion of Science (JSPS), Japan. The authors thank Hui-Tae Park for help with experimentation in the present work.
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2020/7
Y1 - 2020/7
N2 - Yb2SiO5 (ytterbium monosilicate) top coatings and Si bond coat layer were deposited by air plasma spray method as a protection layer on SiC substrates for environmental barrier coatings (EBCs) application. The Yb2SiO5-coated specimens were subjected to isothermal heat treatment at 1400 °C on air for 0, 1, 10, and 50 h. The Yb2SiO5 phase of the top coat layer reacted with Si from the bonding layer and O2 from atmosphere formed to the Yb2Si2O7 phase upon heat treatment at 1400 °C. The oxygen penetrated into the cracks to form SiO2 phase of thermally grown oxide (TGO) in the bond coat and the interface of specimens during heat treatment. Horizontal cracks were also observed, due to a mismatch of the coefficient of thermal expansion (CTE) between the top coat and bond coat. The isothermal heat treatment improves the hardness and elastic modulus of Yb2SiO5 coatings; however, these properties in the Si bond coat were a little bit decreased.
AB - Yb2SiO5 (ytterbium monosilicate) top coatings and Si bond coat layer were deposited by air plasma spray method as a protection layer on SiC substrates for environmental barrier coatings (EBCs) application. The Yb2SiO5-coated specimens were subjected to isothermal heat treatment at 1400 °C on air for 0, 1, 10, and 50 h. The Yb2SiO5 phase of the top coat layer reacted with Si from the bonding layer and O2 from atmosphere formed to the Yb2Si2O7 phase upon heat treatment at 1400 °C. The oxygen penetrated into the cracks to form SiO2 phase of thermally grown oxide (TGO) in the bond coat and the interface of specimens during heat treatment. Horizontal cracks were also observed, due to a mismatch of the coefficient of thermal expansion (CTE) between the top coat and bond coat. The isothermal heat treatment improves the hardness and elastic modulus of Yb2SiO5 coatings; however, these properties in the Si bond coat were a little bit decreased.
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U2 - 10.1016/j.jeurceramsoc.2019.12.057
DO - 10.1016/j.jeurceramsoc.2019.12.057
M3 - Article
AN - SCOPUS:85077689550
SN - 0955-2219
VL - 40
SP - 2667
EP - 2673
JO - Journal of the European Ceramic Society
JF - Journal of the European Ceramic Society
IS - 7
ER -