Effect of TGO thickness on the thermal barrier coatings life under thermal shock and thermal cycle loading

Torkashvand, Kaveh; Poursaeidi, Esmaeil; Mohammadi, Maryam

doi:10.1016/j.ceramint.2018.02.140

Cited by 71 publications

(23 citation statements)

References 24 publications

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“…Therefore, the difference between the durability of the two types of TBCs depended on other factors in the absence of TGO thickness. It has been well documented that the sintering [11][12][13][14][15][58][59][60][61], gradient thermal cycling temperature [16][17][18][19], and roughness of bond coat/topcoat interface [7,[20][21][22][23] also affect the durability of samples. In this case, these other factors were all identical in these two types of TBCs, except for the microstructures of the bond coats.…”

Section: Thermal Cyclic Lifetime Of Tbcsmentioning

confidence: 99%

“…In comparison, mixed oxides such as chromia (Cr 2 O 3 ), spinel ((Ni, Co) (Cr, Al) 2 O 4 ), and nickel oxide (NiO) [7,8,49,51], dramatically deteriorates the durability of TBCs. The results show that mixed oxides generated in TBCs during tests are quite limited, and thus the influence of mixed oxides on the lifetime of TBCs in this case can be ignored, as the TBCs failure mode is mainly related to TGO thickness [10,20,24,57]. In order to further determine the mechanism of the coating fracture, the surface morphologies of TBC samples after YSZ spallation were examined, as shown in Figure 7.…”

Section: Failure Modes Of Tbcs With Double-layer Bond Coatsmentioning

confidence: 99%

“…The spallation of the ceramic topcoat, typically made of yttria-stabilized zirconia (YSZ), is one of the factors that hinders the service of TBCs. The failure of atmospheric plasma-sprayed (APS) TBCs can be affected by many factors, such as TGO growth [1,2,[4][5][6][7][8], thermal expansion mismatch [1,[8][9][10], YSZ sintering [11][12][13][14][15], the temperature gradient across YSZ coating [16][17][18][19] and the profile of the bond coat surface [7,[20][21][22][23], etc. Thermal expansion mismatch between the YSZ coating and the substrate is one of the most critical factors that presently affects the durability of TBCs [9,10,19,24,25].…”

Section: Introductionmentioning

confidence: 99%

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The Evaluation of Durability of Plasma-Sprayed Thermal Barrier Coatings with Double-layer Bond Coat

Peng

Dong

et al. 2019

Coatings

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The durability of atmospheric plasma-sprayed thermal barrier coatings (APS TBCs) with a double-layer bond coat was evaluated via isothermal cycling tests under 1120 °C. The bond coat consisted of a porosity layer deposited on the substrate and an oxidation layer deposited on the porosity layer. Two types of double-layer bond coats with different thickness ratios of the porosity layer to the oxidation layer (type A: 1:2 and type B: 2:1, respectively) were prepared. The results show that the porosity layer was oxidation free, the oxidation layer included a fraction of well-distributed α-Al2O3. The coefficient of thermal expansion of the oxidation layer was about 11.2 × 10−6 K−1, which was rather lower than that of the porosity layer. Thus, the oxidation layer can be regards as a secondary bond coat between ceramic topcoat and traditional bond coat. The thermal cyclic lifetime of type A TBCs was about 60 cycles, which exceeded 1.2 times the durability of type B TBCs. The delamination cracks in both TBCs all propagated in the ceramic topcoat, which were all identical to those in traditional TBCs. Therefore, the design of the double-layer bond coat affected the stress level rather than the stress distribution in TBCs.

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Section: Thermal Cyclic Lifetime Of Tbcsmentioning

confidence: 99%

Section: Failure Modes Of Tbcs With Double-layer Bond Coatsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Evaluation of Durability of Plasma-Sprayed Thermal Barrier Coatings with Double-layer Bond Coat

Peng

Dong

et al. 2019

Coatings

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“…In this test, first, in order to oxides within the BC expand and TGO layer at BC/TC interface forms, the samples experienced isothermal loading for various time exposure (0, 24, 72 and 120h) and then, thermal shock test was performed. In this test, the temperature of sample went from room temperature to 1000 °C in 3 minutes and cooled down in 45 seconds using water quenching method, a detailed explanation of this method can be seen in literature [15]. Figure 1(a) shows a region within the BC area which is oxidized during the APS process.…”

Section: Thermal Shockmentioning

confidence: 99%

Air Plasma Sprayed Bond Coat Oxidation Behavior and its Resistance to Isothermal and Thermal Shock Loading

2019

IJE

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A B S T R A C TAn experimental investigation was conducted to find the effect of spraying method of coating of Thermal Barrier Coatings (TBCs) on their oxidation behaviour and resistance to various thermal loading. Isothermal and thermal shock tests were performed in order to study oxidation behaviour of air plasma sprayed Bond Coat (BC) and assess its effect on TBCs lifetime under the stated loadings. Specimens, after loading were investigated using Field Emission Scanning Electron Microscopy (FE-SEM). Results showed in spite of forming various oxide layers within the BC its oxidation in Bond Coat/Top Coat interface behave the same as samples coated by other methods and no failure was observed at substrate/BC interface or within the BC.

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“…A TBC is a multilayer coating that consists of ceramic top coat, metallic bond coat dan Thermally Grown Oxide (TGO) layer that forms during the operation of a TBC [9], [10]. At high temperature ambiences, TGO is formed between the bond coat and the top coat due to high contents of aluminum in the bond coat alloy which reacts with oxygen [11], [12].…”

Section: Introductionmentioning

confidence: 99%

The Thermal Conductivity of 8 Yttria Stabilized Zirconia and Mullite Thermal Barrier Coating on Medium Carbon Steel Substrate

Zaini*,

Adenan*,

Saedon

et al. 2019

IJEAT

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Thermal conductivity is one of the main features of a thermal barrier coating (TBC) that is important in making sure that the TBC gives its best functionality to the system. A good TBC has low thermal conductivity, so that the temperature can drop across the coating which allows the system to operate in extremely high temperatures. There are several factors that can influence the thermal conductivity of the TBC such as the type of ceramic material used, the deposition method and the physical features of the TBC itself. For this research, air plasma spray (APS) is used to deposit 8 wt% yttria stabilized zirconia (8YSZ) and mullite on medium carbon steel substrates to study their respective thermal conductivities. The aim here is to develop a heat shield using TBC to protect the electric motor in an electrical turbocompounding system. The characteristics of the deposited TBC such as microstructure, element composition, phases and thermal conductivity are studied. The thermal conductivity is reduced when medium carbon steel substrate deposited with TBC. The thermal conductivity of 8YSZ, mullite and uncoated sample at minute 60 is 0.868 W/mK, 0.903 W/mK and 1.057 W/mK, respectively. Therefore, the deposition of 8YSZ TBC can lower the thermal conductivity of the medium carbon steel heat shield.

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Effect of TGO thickness on the thermal barrier coatings life under thermal shock and thermal cycle loading

Cited by 71 publications

References 24 publications

The Evaluation of Durability of Plasma-Sprayed Thermal Barrier Coatings with Double-layer Bond Coat

The Evaluation of Durability of Plasma-Sprayed Thermal Barrier Coatings with Double-layer Bond Coat

Air Plasma Sprayed Bond Coat Oxidation Behavior and its Resistance to Isothermal and Thermal Shock Loading

The Thermal Conductivity of 8 Yttria Stabilized Zirconia and Mullite Thermal Barrier Coating on Medium Carbon Steel Substrate

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