TY - JOUR
T1 - Oxidation and phase structure of the bond coat in EB-PVD thermal barrier coatings during thermal cycling
AU - Li, Meiheng
AU - Sun, Xiaofeng
AU - Zhang, Zhongyuan
AU - Gong, Shengkai
AU - Hu, Wangyu
AU - Guan, Hengrong
AU - Hu, Zhuangqi
PY - 2002/1
Y1 - 2002/1
N2 - After depositing Ni-30Cr-12Al-0.3Y (mass fraction, %) bond coat on a Ni base single crystal superalloy by magnetron sputtering, a ceramic top coat (7%Y2O3-ZrO2) was deposited by electron beam-physical vapor deposition (EB-PVD). During thermal cycles, the Y2O3 content in non-equilibrium phases t′-ZrO2 decreased gradually and the t′-ZrO2 decomposed gradually to equilibrium t-ZrO2 (transforming to monoclinic phase after cooling) and cubic ZrO2 phase. After 200 thermal cycles, the thermally grown oxides (TGO) layer with 3 μm thickness consists of Al2O3 exclusively, indicating that the sputtered Ni-Cr-Al-Y coating is suitable as bond coat for EB-PVD thermal barrier coatings. With increasing thermal cycles, a small amount of monoclinic m-ZrO2 formed from t-ZrO2. Al was depleted, and NiO and Ni(Al, Cr)2O4 formed near the interface between TGO and bond coat. Stress concentration due to oxide growth and phase transformation between t-m ZrO2 would weaken the combination between top and bond coats, and then cause thermal barrier coating to spall from the substrate.
AB - After depositing Ni-30Cr-12Al-0.3Y (mass fraction, %) bond coat on a Ni base single crystal superalloy by magnetron sputtering, a ceramic top coat (7%Y2O3-ZrO2) was deposited by electron beam-physical vapor deposition (EB-PVD). During thermal cycles, the Y2O3 content in non-equilibrium phases t′-ZrO2 decreased gradually and the t′-ZrO2 decomposed gradually to equilibrium t-ZrO2 (transforming to monoclinic phase after cooling) and cubic ZrO2 phase. After 200 thermal cycles, the thermally grown oxides (TGO) layer with 3 μm thickness consists of Al2O3 exclusively, indicating that the sputtered Ni-Cr-Al-Y coating is suitable as bond coat for EB-PVD thermal barrier coatings. With increasing thermal cycles, a small amount of monoclinic m-ZrO2 formed from t-ZrO2. Al was depleted, and NiO and Ni(Al, Cr)2O4 formed near the interface between TGO and bond coat. Stress concentration due to oxide growth and phase transformation between t-m ZrO2 would weaken the combination between top and bond coats, and then cause thermal barrier coating to spall from the substrate.
KW - Bond coat oxidation
KW - Phase transformation
KW - Thermal barrier coating
KW - Thermal cyclic
UR - https://www.scopus.com/pages/publications/0036308778
M3 - 文章
AN - SCOPUS:0036308778
SN - 0412-1961
VL - 38
SP - 79
EP - 83
JO - Jinshu Xuebao/Acta Metallurgica Sinica
JF - Jinshu Xuebao/Acta Metallurgica Sinica
IS - 1
ER -