Sintering induced the failure behavior of dense vertically crack and lamellar structured TBCs with equivalent thermal insulation performance

Cheng, Bo; Yang, Ning; Zhang, Qiang; Zhang, Meng; Zhang, Yuming; Li, Chang-Jiu; Yang, Guan–Jun

doi:10.1016/j.ceramint.2017.08.092

Cited by 65 publications

(20 citation statements)

References 37 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%

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%

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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“…It is widely thought that both the phase transformation of the metastable T' phase and the sintering-induced stiffening of the top coating would contribute to the failure of a typical YSZ top coating. However, the phase transformation from T' phase to the M + C phases needs a long and even incubation period at a very high temperature [15][16][17]. In addition, the sintering induced stiffening should be significant to a sufficient level before spalling failure, and this would allow a very long service lifetime, even at high temperatures [18][19][20][21][22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Yttria-Stabilized Zirconia Hollow Sphere with Reduced Shell Thickness by Controlling Ambient Temperature during Plasma Process

et al. 2018

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Yttria-stabilized zirconia (YSZ) hollow sphere (HS) powder is a novel potential feedstock material for the plasma spraying of next generation advanced thermal barrier coatings with low thermal conductivity and high sintering resistibility. In this study, YSZ HS powders were prepared by plasma treatment with/without a heat preservation zone around the flying path of the particles during plasma flame. The results of the scanning electron microscopy of YSZ HS powders showed that HS prepared with a heat preservation zone during the plasma process exhibited a regular spherical morphology and a homogeneous thin shell structure. Due to the sufficient heating of the shell regions, the HS powder presented a well densified shell structure. Furthermore, the mechanism of formation of the HS powder with reduced shell thickness was also discussed based on the analysis of the evolution of the powder structure. This kind of hollow sphere powder with a very thin shell structure provides a new alternative feedstock material for the development of next generation high performance thermal barrier coatings.In general, the top coating is fabricated by atmospheric plasma spraying (APS) supplemented by electron beam physical vapor deposition (EB-PVD) and plasma spray physical vapor deposition (PS-PVD) [32][33][34][35][36][37][38]. During the plasma spray, powder with a diameter of around 50 µm is injected into the plasma flame. The powder is melted rapidly and at the same time becomes accelerated in the plasma flame. These molten droplets with high velocities impact and spread on the surface of the substrate, then form splats after solidification. The top coating consists of overlapped splats and defects such as pores and cracks. According to the morphology, the pores in the APS TBCs can be divided into three groups: globular pores, inter-splat pores, and intra-splat pores. Among the three types of pores, the inter-splat and intra-splat pore structures play an important role in determining the thermal and mechanical properties of the top coating. Considering the significant dependence of pore healing behavior on the pore structure [39][40][41][42], the lamellar structure of the top coating is a key factor in creating high performance and long lifetime TBCs [43][44][45][46][47]. As all three types of pores are formed during the splat solidification and cooling process, the microstructure and the properties of the top coating significantly depend on both the spraying parameters and characteristics of the feedstock powder used [48][49][50][51][52][53][54][55][56][57][58]. Therefore, new feedstock powders with a large surface area are highly expected for the next generation advanced TBCs.The following three morphologies of YSZ powder are commonly used for APS YSZ top coatings according to its manufacturing design: fused and crushed (FC) powder with an angular appearance and dense inner structure; agglomerated and sintered (AS) powder with a spherical appearance, coarse surface and porous inner structure; and plasma processed hollow sphere (...

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“…However, if the geometry is asymmetrical, it leads to an antisymmetric stress distribution, resulting in an extra stress moment on one side and a higher stress on the other side in order to balance the stresses within the TC. Consequently, the highest tensile stress (grey part in Although the overall stresses within SPS TCs with VCs are much higher than that in the TBC without VCs, VC structured TCs nevertheless demonstrate longer lifetimes than that of APS TCs [140]. The rational for this phenomenon can be further analyzed as follows.…”

Section: Influences Of Tc Creep and Sinteringmentioning

confidence: 95%

“…After the constraint is released and the in-plane stress reverts again to less than σs, sintering will continue [137]. For SPS TCs, the initial E* (146 GPa) is higher than APS TCs (usually << 100 GPa [138,139,140]), so the in-plane stress can build up quickly to hinder sintering; this also explains why VCs are easier to form in SPS TCs. In addition, during the first 800 h at the elevated temperature, the in-plane tensile stress is high enough to generate fresh VCs and to impede sintering.…”

Section: Sintering Resistance Of Sps Tcsmentioning

confidence: 99%

“…Based on the results of this study as well as that discussed ref. [140] on SPS TCs, some cracks within the TC may penetrate through the TGO and propagate within the interface between TGO and BC, however, this will not be considered as the main cause for SPS TBC failure. On the contrary, cracks generated at imperfections of the TGO and propagated horizontally within the TC can lead to the ultimate failure of a TBC system.…”

Section: Suitability Of Cnd Model For Sps Tbcmentioning

confidence: 99%

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Suspension Plasma Spray Thermal Barrier Coating Systems - Modelling and Performance Characterization Under Isothermal and Cyclic Oxidation Conditions

Xiao¹

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Sintering induced the failure behavior of dense vertically crack and lamellar structured TBCs with equivalent thermal insulation performance

Cited by 65 publications

References 37 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

Preparation of Yttria-Stabilized Zirconia Hollow Sphere with Reduced Shell Thickness by Controlling Ambient Temperature during Plasma Process

Suspension Plasma Spray Thermal Barrier Coating Systems - Modelling and Performance Characterization Under Isothermal and Cyclic Oxidation Conditions

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