Journal of the Korean institute of surface engineering (한국표면공학회지)

The Korean Institute of Surface Engineering (한국표면공학회)
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A Syudy on the High Temprerties of the 5Layer Functionally Gradient Thermal Barrier Coating

5층열장벽 피막의 고온 물성에 관한연구

  • Han, J. C. (Dept. of Material Engineering, Hankuk Aviation University) ;
  • Jung, C. (Dept. of Material Engineering, Hankuk Aviation University) ;
  • Song, Y. S. (Dept. of Material Engineering, Hankuk Aviation University) ;
  • Yoon, J. K. (National Institute of Technolodge & Quality) ;
  • Lo, B. H. (Korea Institute of Machinery & Materials) ;
  • Lee, K. H. (Korea Institute of Machinery & Materials)
  • 한주철 (한국항공대학교 항공재료공학과) ;
  • 정철 (한국항공대학교 항공재료공학과) ;
  • 송요승 (한국항공대학교 항공재료공학과) ;
  • 윤종구 (국립기술품질원) ;
  • 노병호 (한국기계연구원) ;
  • 이구현 (한국기계연구원)
  • Published : 1998.02.01
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Abstract

The Thermal Barrier Coating(TBC) has been used to improve the heat barrier and tribological properties of the aircraft engine and the automobile engine in high temperature. Especially, the high temperature tribological propertied of the cylinder haed and the piston crown of diesel engine was emphasized. Therefore, the purpose of this work was to evaluate the microstructure, tribological propeer in high tempearmal shock resistance and bonding strength of five layer functionally gradient TBC for the applications. The five layerwere composed with 100% ceramic insulating later, 75(ceramic):25 (metal) layer, 50:50 layer, 25:75 layer and 100% metal bonding layer to redude the thermal stress. the YSL and MSL poweders were the insulation ceramics powers. The NiCrAly, Inconel625 and SUS powders were the bonding and mixingg powders for plasma spray process. According to the result of high temperature wear test, the wera resistance of YSZ/NiCrAlY siytem was most out standing at 600 and $800^{\circ}C$. At $400^{\circ}C$, the wear resistance of YSZ/Inconel system was better than others. Wear volume at other temperature because of the low temperature degration of zirconia. The thermal shock mechanism of 5 later is the vertical crack gegration in insulating layer. this means that the initial cracks were generated in the top layer, and then developed into the composite layers during thermal shock test. Finally, these cracks werereached to the interface of coating and substrate and also, these vertioal cracks join with the horizontal cracks of the each layers. The bonding strength of YSZ/NiCrAlY and YSZ/Inconel 5 layer system is better than other 5layer systems. The theramal shock resistance of thermal barrier coating s with 5 layer system is better than that of 3 layers and 2 layers.

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