Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Evaluation of Degradation of Isothermally Aged Plasma-Sprayed Thermal Barrier Coating

플라즈마 용사 열차폐 코팅의 열화 평가

  • 구재민 (성균관대학교 기계공학부) ;
  • 석창성 (성균관대학교 기계공학부) ;
  • 강민성 (성균관대학교 기계공학부) ;
  • 김대진 (성균관대학교 기계공학부) ;
  • 이동훈 (현대제철 생산공정팀) ;
  • 김문영 (한전 KPS(주) GT 정비기술센터)
  • Published : 2010.04.01
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Abstract

The thermal barrier coating of a gas turbine blade was degraded by isothermal heating in a furnace and by varying the exposure time and temperature. Then, a micro-Vickers hardness test was conducted on the cross section of the bond coat and Ni-based superalloy substrate. Further, the thickness of TGO(Thermally Grown Oxide) was measured by using an image analyzer, and the changes in the microstructure and element contents in the coating were analyzed by using an optical microscope and by performing SEM-EDX analysis. No significant change was observed in the Vickers hardness of the bond coat when the coated specimen was degraded at a high temperature; delamination was observed between the top coat and the bond coat when the coating was degraded for 50 h at a temperature $1,151^{\circ}C$.

가스터빈 블레이드는 터빈 가동 시 발생하는 고온화염으로부터 블레이드를 보호하고, 구조물의 표면 온도를 안전한 수준으로 낮추기 위하여 블레이드 표면에 열차폐 코팅(TBC; Thermal barrier coating)을 하여 사용하고 있다. 본 논문에서는 가스터빈 1단 블레이드에 적용되는 코팅 방식을 이용하여 코인형 시험편을 제작하였고 열화 온도 및 유지 시간의 변화에 따른 코팅 계면 산화물의 성장 거동을 분석하였다. 코팅 단면에 대하여 코팅 계면 산화물의 두께와 마이크로 비커스 경도를 측정하여 열화 특성을 평가 하였다. 또한 성분분석을 통하여 미세조직의 변화를 관찰함으로써 열차폐 코팅의 열적 열화특성을 평가하였다.

Keywords

References

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Cited by

  1. Durability Evaluation of Thermal Barrier Coating (TBC) According to Growth of Thermally Grown Oxide (TGO) vol.38, pp.12, 2014, https://doi.org/10.3795/KSME-A.2014.38.12.1431
  2. Analysis of Degradation Mechanism for Single Crystal Blade and Vane in Gas Turbine vol.35, pp.5, 2011, https://doi.org/10.3795/KSME-A.2011.35.5.549