Cyclic Hot Corrosion Failure Behaviors of EB-PVD TBC Systems in the Presence of Sulfate and Vanadate Molten Salts

Ozgurluk, Yasin; Döleker, Kadir Mert; Özkan, Derviş; Ahlatçı, Hayrettin; Karaoğlanlı, Abdullah Cahit

doi:10.3390/coatings9030166

Cited by 45 publications

(20 citation statements)

References 32 publications

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“…When the stress value exceeds the allowable stress of ceramic materials, crack propagation occurs in the ceramic layer. Note that corrosion failure, such as CMAS, is also an important mechanism of coating failure [ 25 , 26 , 27 , 28 , 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Understanding the Failure Mechanism of Thermal Barrier Coatings Considering the Local Bulge at the Interface between YSZ Ceramic and Bond Layer

Wei

Cai

2021

Materials

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The TC/BC interface morphology in APS TBC is one of the important factors leading to crack propagation and coating failure. Long cracks are found near the bulge on the TC/BC interface. In this study, the TBC model with the bulge on the interface is developed to explore the influence of the bulge on the coating failure. Dynamic TGO growth and crack propagation are considered in the model. The effects of the bulge on the stress state and crack propagation in the ceramic layer are examined. Moreover, the effects of the distribution and number of bulges are also investigated. The results show that the bulge on the interface results in the redistribution of local stress. The early cracking of the ceramic layer occurs near the top of the bulge. One bulge near the peak or valley of the interface leads to a coating life reduction of about 75% compared with that without a bulge. The increase in the number of bulges further decreases the coating life, which is independent of the bulge location. The results in this work indicate that a smooth TC/BC interface obtained by some possible surface treatments may be an optional scenario for improving coating life.

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Section: Introductionmentioning

confidence: 99%

Understanding the Failure Mechanism of Thermal Barrier Coatings Considering the Local Bulge at the Interface between YSZ Ceramic and Bond Layer

Wei

Cai

2021

Materials

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“…The most common material used as the ceramic topcoat is 3.4-4.5 mol% yttria-stabilized zirconia (YSZ) [1,2,4,6], applied either by electron beam physical vapor deposition (EBPVD) or atmospheric plasma spraying (APS). From a mechanical point of view, durability and failure mechanisms of TBCs are thoroughly described and discussed by Evans et al [7] in their paper from 2001, and more details on failure due to hot corrosion, oxidation, erosion and thermal shock is reported in [8][9][10][11][12]. Of particular interest to aircraft engines is the ingestion of siliceous particulates (dust, sand, volcanic ash, runway debris) with the intake of air.…”

Section: Introductionmentioning

confidence: 99%

Phase relations and thermomechanical properties of (Gd2Zr2O7)1−x(YbSZ)x based thermal barrier coatings (0 ≤ x ≤ 0.98)

Tabeshfar

Salehi

Dini

et al. 2021

Journal of Materials Research

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Doped Gd2Zr2O7 materials have interesting properties as thermal barrier coatings (TBC) to replace the YSZ topcoats traditionally used. Here we investigate the thermomechanical properties and phase relations of Gd2Zr2O7 (GZO) alloyed with 5 mol% Yb2O3 stabilized ZrO2 (YbSZ) in the composition range (Gd2Zr2O7)1−x(YbSZ)x, 0 ≤ x ≤ 0.98. With increasing YbSZ content, phase transformations from ordered to disordered pyrochlore to fluorite and tetragonal structures were observed. The thermal expansion coefficient (TEC) and Vickers hardness were correlated showing a maximum hardness (~ 11.5 GPa) and minimum TEC at x = 0.82. At 1000 °C, the TEC for the end members, x = 0 and 0.98, were 11.4 and 11.3 × 10–6 K−1, respectively. The fracture toughness, KIC, showed an average value around 1.5 MPa m0.5 for x ≤ 0.93 and increased significantly at x = 0.98 reaching 5.4 MPa m0.5 due to the presence of a ferroelastic phase. For TBC applications, compounds with x = 0.98 show promise due to high TEC and high KIC. Graphic abstract Fig. 5a summarize the most important results in the manuscript. Showing a significant increase in fracture toughness for compositions with x=0.98.

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“…Thus, the research for novel materials for application at high temperature is required. To ensure increased oxidation resistance, the protective coatings are applied on the surface of elements manufactured from Ni-based alloys, such as aluminide layers [2][3][4][5], MCrAlY-type coatings [6][7][8][9] or complete thermal barrier coatings (TBC) [10][11][12][13]. However, the research for alternative materials for potential replacement of Ni-based alloys is still required.…”

Section: Introductionmentioning

confidence: 99%

Increase in Oxidation Resistance of MAR M-509 via LA-CVD Aluminizing

et al. 2021

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Due to their excellent mechanical properties, Co-based alloys are one of the main candidates to replace Ni-based alloys in high temperature application. Knowledge about oxidation resistance of Co-based alloy MAR M-509 and the extent of its aluminizing on its oxidation resistance is limited. Therefore, in the present study, an aluminide layer was manufactured by low activity chemical vapor deposition (LA-CVD) on MAR M-509. Aluminized and uncoated alloys were investigated in terms of oxidation kinetics and oxidation resistance during isothermal and cyclic oxidation at 1000 and 1100 °C. Material in the as-cast and after exposure was analyzed using scanning electron microscopy (SEM), thermogravimetry (TG) and glow-discharge optical emission spectrometry (GD-OES). Obtained results allowed for elucidating of degradation mechanism including nitridation process of carbides for MAR M-509. It was found that aluminizing of MAR M-509 significantly decreases its oxidation kinetics by the factor of 2.5 and 1.5 at 1000 and 1100 °C respectively. Moreover, the suppression of identified degradation mechanism in case of aluminized alloy was found until occurrence of breakaway oxidation of the aluminide layer. It was also proposed that further increase in oxidation resistance can be successively achieved by an increase in aluminide layer thickness.

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Cyclic Hot Corrosion Failure Behaviors of EB-PVD TBC Systems in the Presence of Sulfate and Vanadate Molten Salts

Cited by 45 publications

References 32 publications

Understanding the Failure Mechanism of Thermal Barrier Coatings Considering the Local Bulge at the Interface between YSZ Ceramic and Bond Layer

Understanding the Failure Mechanism of Thermal Barrier Coatings Considering the Local Bulge at the Interface between YSZ Ceramic and Bond Layer

Phase relations and thermomechanical properties of (Gd2Zr2O7)1−x(YbSZ)x based thermal barrier coatings (0 ≤ x ≤ 0.98)

Increase in Oxidation Resistance of MAR M-509 via LA-CVD Aluminizing

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