Effect of Oxidation of Bond Coat on Failure of Thermal Barrier Coating

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J. Korean Ceram. Soc. > Volume 34(1); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(1): 88.

Bond Coat의 산화가 Thermal Barrier Coating의 파괴에 미치는 영향

최동구, 최함메, 강병성, 최원경, 최시경, 김재철¹, 박영규¹, 김길무¹

한국과학기술원 재료공학과
¹충남대학교 재료공학과

Effect of Oxidation of Bond Coat on Failure of Thermal Barrier Coating

ABSTRACT

The oxidation behavior of the NiCrAlY bond coat and thermal fatigue failure in the plasma-sprayed thermal barrier coating system, ZrO2.8wt%Y2O3 top coat/Ni-26Cr-5Al-0.5Y bond coat/Hastelloy X superalloy substrate, in commercial use for finned segment of gas turbine burner were investigated. The main oxides formed in the bond coat were NiO, Cr2O3, and Al2O3. It divided the oxide distribution at this interface into two types whether an Al2O3 thin layer existed beneath ZrO2/bond coat interface before operation at high temperature or not. While a continuous layer of NiO was formed mainly in the region where the Al2O3 thin layer was present, the absence of it resulted in the formation of mixture of Cr2O3 and Al2O3 beneath NiO layer. Analyses on the fracture surface of specimen spalled by thermal cycling showed that spalling occurred mainly along the ceram-ic coat near ZrO2/bond coat oxide layer interface, but slightly in the oxide layer region.