2002 Fiscal Year Final Research Report Summary
Improvement of Oxidation and Delamination Resistant Properties in Thermal Barrier Coatings by Means of Plasma Thermal Spraying
| Project/Area Number |
13450041
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Tohoku University |
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Principal Investigator |
SHOJI Tetsuo Tohoku Univ, Graduate school of Engineerlng, Prof., 大学院・工学研究科, 教授 (80091700)
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| Co-Investigator(Kenkyū-buntansha) |
SATO Takehiko Tohoku Univ, Institute for Fluid Science, Assist,Prof., 流体科学研究所, 講師 (10302225)
YOKOBORI Toshimitu Tohoku Univ, Graduate School of Engineering, Prof., 大学院・工学研究科, 教授 (00124636)
NISHIYAMA Hideya Tohoku Univ, Institute for Fluid Science, Prof., 流体科学研究所, 教授 (20156128)
OGAWA Kazuhiro Tohoku Univ, Graduate School of Engineering, Assoc,Prof., 大学院・工学研究科, 助教授 (50312616)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Thermal Barrier Coating(TBC) / Thermally Grown Oxide (TGO) / Bond coating / Cerium (Ce) / Silicon (Si) / Four Point Bending / Laser remelting |
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| Research Abstract |
We suggested that degradation of thermal barrier coating (TBC) was induced by thermal stress due to formation and growth of thermally grown oxide (TGO) in YSZ top coat and MCrAlY bond coat, and by the decrease in bonding strength due to formation of many pores in TGO. In order to inhibit of formation of pores in TGO, an improvement of chemical composition of bond coat material was considered. Ce and Si added MCrAlY bond coat material was developed. As a result, morphology of the TGO changed drastically, namely TGO grew up from the interior of the bond coat like wooden root (wedge shaped TGO). Furthermore, the developed material also inhibited the growth of nickel and cobalt oxides, which have bad influence on formation of pores. And four point bending test was carried out to evaluated the interface strength. The strain of developed bond coat material used for TBC was three times higher than conventional one. Accordingly, the improvement of delamination resistant property using the developed bond coat material was successful.
Also, a technique of laser remelting to a bond coat was developed to improve the oxidation resistant property. An objective of laser remelting is to produce a dense and less impure TGO. As a result, if conventional bond material (MCrAlY) was used, TGO thickness decreased and dense alumina formed. Moreover, laser remetled TBC was found to have stronger bending strength than the standard TBC, probably due to disappearance of pores in TGO.
The improvement of oxidation and delamination resistant properties was succeeded by means of modification of bond coat material and usage of laser remelting technique.
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