TEM analysis of the microstructure of thermal barrier coatings after isothermal oxidation

Poza, P.; Gómez-García, J.; Múnez, C.J.

doi:10.1016/j.actamat.2012.09.028

Cited by 47 publications

(14 citation statements)

References 25 publications

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“…The TGO not only grows on the surface of BC but also grows inside the BC [26]. The area percentage of TGO in BC is easy to calculate with the aid of IPP software.…”

Section: Thermal Cycle Testmentioning

confidence: 99%

Effect of TiC self-healing coatings on the cyclic oxidation resistance and lifetime of thermal barrier coatings

Ouyang

Yasir

et al. 2016

Journal of Alloys and Compounds

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“…The TGO not only grows on the surface of BC but also grows inside the BC [26]. The area percentage of TGO in BC is easy to calculate with the aid of IPP software.…”

Section: Thermal Cycle Testmentioning

confidence: 99%

Effect of TiC self-healing coatings on the cyclic oxidation resistance and lifetime of thermal barrier coatings

Ouyang

Yasir

et al. 2016

Journal of Alloys and Compounds

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“…It is expected that some changes in the growth mode of TGO have occurred. Recent TEM studies reported some as-coated TGO as thick as 0.3 m [18][19][20][21], consisting of -Al 2 O 3 and other meta-stable phases ( or ). When the as-coated TGO …”

Section: Discussionmentioning

confidence: 99%

“…According to a TEM study [20], TBC applied by air plasma onto an Inconel 600 Ni base alloy and treated at 950°C for 144 h showed a double-layered TGO layer, an outer Al+O layer and an inner Al+Cr+O layer, at some locations. At 1050°C, NiAl 2 O 4 spinels, after 72 h exposure, and NiO, after 336 h, formed at the "TC side" of the TGO layer.…”

Section: Discussionmentioning

confidence: 99%

Effects of vacuum treatment on the formation of TGO in YSZ-TBC on IN738LC — An interpretation of EDX line-scan data

2014

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This study examined the effects of vacuum heat-treatment on the growth of oxide (thermally grown oxide, TGO) between the ceramic top coat (yttria-stabilized zirconia, YSZ) and the metallic bond coat (NiCrAlY) of a thermal barrier coating (TBC). For the investigation, IN738LC coupons coated with a TBC were heat-treated in vacuum and/or isothermally oxidized at 1200°C and then microscopically analyzed using SEM and EDX. The introduction of heat treatment in vacuum before isothermal oxidation resulted in a reduction of the TGO thickness and the number of interface cracks around the TGO layers. These TGO layers were further analyzed using EDX line scan data in terms of the dependence of the EDX Al intensity on the O intensity. The analysis showed that the TGO layers in the coupons only oxidized in air were divided into two sub-layers with respect to the gradient of the Al intensity on the O intensity. The pre-treatment in vacuum nullified this division and reduced cracks at the interfaces. The effects of the treatment in vacuum on the behavior of TGO and TBCs were analyzed and compared with the data obtained for a TBCcoated turbine blade serviced for a land-based heavy duty gas turbine.

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“…To the best of author's knowledge, so far, no work has been reported on the suspension plasma spray of GZ/YSZ multilayered TBCs and not much work is seen on the isothermal oxidation studies of GZ based TBCs. Also, most of the isothermal oxidation studies on YSZ reported so far are in the range of 1100°C or below . This study aimed at comparing the isothermal oxidation performance of GZ/YSZ multilayered TBCs with the standard 8YSZ single‐layer TBC at a higher temperature (1150°C).…”

Section: Introductionmentioning

confidence: 98%

“…Also, most of the isothermal oxidation studies on YSZ reported so far are in the range of 1100°C or below. [19][20][21][22][23] This study aimed at comparing the isothermal oxidation performance of GZ/YSZ multilayered TBCs with the standard 8YSZ single-layer TBC at a higher temperature (1150°C). Single-layer YSZ, doublelayer GZ/YSZ, and triple-layer GZdense/GZ/YSZ with denser gadolinium zirconate on top of GZ/YSZ were suspension plasma sprayed.…”

Section: Introductionmentioning

confidence: 99%

Isothermal Oxidation Behavior of Gd₂Zr₂O₇/YSZ Multilayered Thermal Barrier Coatings

Mahade

Curry

et al. 2016

Int J Applied Ceramic Tech

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Efficiency of a gas turbine can be increased by increasing the operating temperature. Yttria-stabilized zirconia (YSZ) is the standard thermal barrier coating (TBC) material used in gas turbine applications. However, above 1200°C, YSZ undergoes significant sintering and CMAS (calcium magnesium alumino silicate) infiltration. New ceramic materials of rare earth zirconate composition such as gadolinium zirconate (GZ) are promising candidates for thermal barrier coating applications (TBC) above 1200°C. Suspension plasma spray of single-layer YSZ, double-layer GZ/YSZ, and a triple-layer TBC comprising denser GZ on top of GZ/YSZ TBC was attempted. The overall coating thickness in all three TBCs was kept the same. Isothermal oxidation performance of the three TBCs along with bare substrate and bond-coated substrate was investigated for time intervals of 10 h, 50 h, and 100 h at 1150°C in air environment. Weight gain/loss analysis was carried out by sensitive weighing balance. Microstructural analysis was carried out using scanning electron microscopy (SEM). As-sprayed single-layer YSZ and double-layer GZ/YSZ showed columnar microstructure, whereas the denser layer in the triple-layer TBC was not columnar. Phase analysis of the top surface of as-sprayed TBCs was carried out using XRD. Porosity measurements were made by water intrusion method. In the weight gain analysis and SEM analysis, multilayered TBCs showed lower weight gain and lower TGO thickness compared to single-layer YSZ.

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TEM analysis of the microstructure of thermal barrier coatings after isothermal oxidation

Cited by 47 publications

References 25 publications

Effect of TiC self-healing coatings on the cyclic oxidation resistance and lifetime of thermal barrier coatings

Effect of TiC self-healing coatings on the cyclic oxidation resistance and lifetime of thermal barrier coatings

Effects of vacuum treatment on the formation of TGO in YSZ-TBC on IN738LC — An interpretation of EDX line-scan data

Isothermal Oxidation Behavior of Gd₂Zr₂O₇/YSZ Multilayered Thermal Barrier Coatings

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TEM analysis of the microstructure of thermal barrier coatings after isothermal oxidation

Cited by 47 publications

References 25 publications

Effect of TiC self-healing coatings on the cyclic oxidation resistance and lifetime of thermal barrier coatings

Effect of TiC self-healing coatings on the cyclic oxidation resistance and lifetime of thermal barrier coatings

Effects of vacuum treatment on the formation of TGO in YSZ-TBC on IN738LC — An interpretation of EDX line-scan data

Isothermal Oxidation Behavior of Gd2Zr2O7/YSZ Multilayered Thermal Barrier Coatings

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Isothermal Oxidation Behavior of Gd₂Zr₂O₇/YSZ Multilayered Thermal Barrier Coatings