Thermal Cycling Damage and Thermal Barrier Property of TBC.

Ohki, Motofumi; Mutoh, Yoshiharu; Ohara, Minoru; Takahashi, Masashi; Ishibashi, Toshiyuki

doi:10.2207/qjjws.16.395

Cited by 3 publications

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“…However, because TBCs are formed as a composite material of combined thin layer coatings, the essential problem that TBCs can't apply to general materials estimation experiment is obvious. Furthermore, occurrence of TC densification (decreasing TC porosity) with long time high temperature exposure is also reported, 3) changing TC Young's modulus compared with modulus when gas turbines started operation. Therefore, simple, quick, accurate, and non-destructive measurement of TC Young's modulus is needed, but such measurement is not established yet.…”

Section: Introductionmentioning

confidence: 96%

Influence of Load Dependency and Coating Anisotropy on Calculated Young’s Modulus of TBCs by Indentation Test

2006

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Thermal Barrier Coatings (TBCs) are developed as a method for increasing the operation gas temperature of gas turbines for electric power stations, and recently they are applied to 1500 C class gas turbines. On the other hand, they have been reported that the repetition of thermal stress caused by a difference in the thermal expansion coefficient between thermal barrier ceramic layer and metallic layer in TBCs promotes coating damage. Therefore, understanding the accurate value of top-coat (TC) Young's modulus that can estimate the extent of generated thermal stress is necessary to ensure material reliability. However, because TBCs are formed as a composite material of combined thin layer coatings, the essential problem that TBCs can't apply to general materials estimation experiment is obvious.We have studied the estimation of TC Young's modulus by using indentation hardness tests. In the former paper, we reported that the calculated TC Young's modulus for TBCs specimens depends on the indentation load. Therefore, we first discuss such dependency in the present paper. As a result, we clearly show that the reason for the load dependency of the calculated TC Young's modulus below 147 N of indentation load is the effect of under-coat (UC) and calculating TC Young's modulus by using this procedure can eliminate the UC effect until an indentation load of 9.8 N. In addition, we examine the fracture behavior of TC following the indentation process and discuss the reason why does calculated TC Young's modulus decrease above 147 N.We also discuss the influence of TC anisotropy on calculated TC Young's modulus, and then we confirm that the influence of TC anisotropy rarely appears using this procedure.

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Section: Introductionmentioning

confidence: 96%

Influence of Load Dependency and Coating Anisotropy on Calculated Young’s Modulus of TBCs by Indentation Test

2006

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Mechanistic Understanding for Degraded Thermal Barrier Coatings

Ogawa

Shoji

Aoki³

et al. 2001

JSME Int. J., Ser. A

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Effect of Thermal Barrier Coating Layer on HIP Treated IN738LC Fatigue Characteristic

Kuba

Kojima²,

Suzuki

2006

KEM

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The fatigue characteristic of thermal barrier-coated Ni-base superalloy IN738LC at room temperature was studied by fatigue test using SEM-servo testing machine. In order to eliminate the influence of micro-shrinkage in IN738LC and purely investigate the effect of TBC on fatigue characteristic, HIP treated IN738LC was used in comparison with NON-HIP treated one. The results indicate that HIP treatment is effective to remove micro-shrinkage and fatigue life is greatly improved. The TBC coating layer is a strength member in the small test specimen at room temperature, and TBC coated material showed lower fatigue life rather than IN738LC without TBC.

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Thermal Cycling Damage and Thermal Barrier Property of TBC.

Cited by 3 publications

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Influence of Load Dependency and Coating Anisotropy on Calculated Young’s Modulus of TBCs by Indentation Test

Influence of Load Dependency and Coating Anisotropy on Calculated Young’s Modulus of TBCs by Indentation Test

Mechanistic Understanding for Degraded Thermal Barrier Coatings

Effect of Thermal Barrier Coating Layer on HIP Treated IN738LC Fatigue Characteristic

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Thermal Cycling Damage and Thermal Barrier Property of TBC.

Cited by 3 publications

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Influence of Load Dependency and Coating Anisotropy on Calculated Young&rsquo;s Modulus of TBCs by Indentation Test

Influence of Load Dependency and Coating Anisotropy on Calculated Young&rsquo;s Modulus of TBCs by Indentation Test

Mechanistic Understanding for Degraded Thermal Barrier Coatings

Effect of Thermal Barrier Coating Layer on HIP Treated IN738LC Fatigue Characteristic

Contact Info

Product

Resources

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Influence of Load Dependency and Coating Anisotropy on Calculated Young’s Modulus of TBCs by Indentation Test

Influence of Load Dependency and Coating Anisotropy on Calculated Young’s Modulus of TBCs by Indentation Test