Epitaxial grain growth during 8YSZ splat formation on polycrystalline YSZ substrates by plasma spraying

Yang, Er‐Juan; Luo, Xiao-Tao; Yang, Guan-Jun; Takahashi, Makoto

doi:10.1016/j.surfcoat.2015.04.031

Cited by 27 publications

(9 citation statements)

References 36 publications

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“…(Fig. 1c) [16][17] . The EB-PVD TBCs have disadvantages of high cost and high thermal conductivity (Fig.…”

Section: Challenges Of Ps-pvd 7ysz Tbcsmentioning

confidence: 99%

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A solution to the challenges of particle erosion and thermal cycle for PS-PVD 7YSZ thermal barrier coatings

Zhang

et al. 2021

Preprint

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Advanced aero-engine is a key technique that is used all over the world, where many high-temperature components such as turbine blades and combustor, are made of Ni/Co/Fe based superalloys. However, they need high-temperature protection to avoid fast performance degradation. Generally, the superalloy high-temperature components are protected by thermal barrier coatings (TBCs) obtained via an atmospheric plasma spray (APS) and an electron beam-physical vapor deposition (EB-PVD). Here, a novel 3rd generation TBCs process using plasma spray-physical vapor deposition (PS-PVD) is presented, showing a more promising use than the traditional APS and EB-PVD. The PS-PVD feature uses evaporating ceramic powder, which results in the deposition of a feather-like columnar coating. This special microstructure showed good strain tolerance and non-line-of-sight (NLOS) deposition, giving great potential for application. In a working aero-engine, the high-temperature components face a serious environment, where foreign particle erosion is a great challenge and is the first barrier to the application of PS-PVD TBCs. As a solution, an Al-modification approach was proposed in this investigation. The results demonstrate that this approach can improve particle erosion resistance. Also, the thermal cycle performance had an apparent optimization.

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“…(Fig. 1c) [16][17] . The EB-PVD TBCs have disadvantages of high cost and high thermal conductivity (Fig.…”

Section: Challenges Of Ps-pvd 7ysz Tbcsmentioning

confidence: 99%

“…The APS TBCs have a laminar structure obtained through splat deposition, which causes the challenges of low strain tolerance and low bond strength. [16][17] . The EB-PVD TBCs have a columnar structure obtained via vapor-deposited atoms, and they face the challenges of high cost and high thermal conductivity [18][19] .…”

Section: Introductionmentioning

confidence: 99%

A solution to the challenges of particle erosion and thermal cycle for PS-PVD 7YSZ thermal barrier coatings

Zhang

et al. 2021

Preprint

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“…When two successive droplets impinged onto the substrate within a short period of time, the first droplet had been solidified and formed splat/splat interface. The droplet revealed a time-/space-independent feature [43]. In order to further study the thermodynamics and dynamics essence of two droplets, a phase model that can reproduce the flattening and solidification process of two droplets is built and is shown in Fig.…”

Section: Flattening Solidification and Crystallization Behavior Of Tmentioning

confidence: 99%

Experimental and numerical modeling for flattening and rapid solidification with crystallization behavior of supersonic ceramic droplets

Wang

Bai

et al. 2020

Preprint

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Successive impingement of supersonic droplets after refining in plasma jet usually forms a fine-lamellar structured coating with high mechanical properties. However, the comprehensive process (such as flattening, rapid solidification and crystallization) of high-velocity impact of refined droplets is difficult to understand. In this study, an experimental study showed that the content of refinement droplets reached to 90 % and displayed the multi-scale equiaxed grains morphology at extremely rapid solidification rate. Phase-field model revealed a hybrid coalescence growth of oriented attachment and migration of grains boundary under the dynamic temperature gradient. Furthermore, an optimized numerical model that consisted of the Navier-Stokes and energy balance equations coupled with the Cahn-Hilliard and phase-field model for growth orientation of grains was developed to accurately reproduce the comprehensive process of refined supersonic droplets. The size distribution and crystallographic orientation of columnar grains for single or two flattened droplets were in a good agreement with the experimental results. The interface between two-flattened droplets exhibited an epitaxial growth of columnar grains. This optimized model can be an effective method in predicting the flattening and solidification with crystallization behavior of droplets during plasma spraying.

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“…A number of studies have addressed the grain structure of thermallysprayed single splats, mainly focussing on plasma spray and ceramic materials. The effect of substrate preheating on the splat grain structure has also been assessed by Yang et al, [14]. The authors observed that epitaxial Al 2 O 3 splats can be formed on α − Al 2 O 3 substrates at 900 • C. Co-Cr coatings have been analysed by Lau et al, [15], where a nanocrystalline structure of 21 nm average grain size was detected by analysis of X-ray diffraction lines.…”

Section: Crystallisation and Solidificationmentioning

confidence: 99%

Residual stress and adhesion of thermal spray coatings: Microscopic view by solidification and crystallisation analysis in the epitaxial CoNiCrAlY single splat

et al. 2018

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A new approach is proposed to achieve an in-depth understanding of crystallisation, residual stress and adhesion in epitaxial splats obtained by Combustion Flame Spray. Modelling of the fundamental process mechanisms is achieved with the help of experimental observations providing details with a sub-micrometre spatial resolution. At this scope, High Angular Resolution Electron Backscatter Diffraction and Transmission Electron Microscopy analysis are employed to provide insights into crystallisation and residual stress levels, while FIB-milled microcantilever beam bending is used for fracture strength measurements in the case of single splats. A comparison to fully-developed coatings is achieved by employing the X-ray Diffraction sin 2 ψ technique and pull-off methods for residual stress and fracture strength, respectively. The methodology is applied to metallic CoNiCrAlY material sprayed onto a Ni-based superalloy substrate. The establishment of different crystallisation regions: epitaxial and polycrystalline, is the result of variations in the heat flux direction at the solidification front. Significant dislocation density is also reported, indicating the relevance of impact dynamics and plastic deformation mechanisms. The comparison with fully-developed coatings suggests a reduction in inter-splat bonding at splat overlapping.

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Epitaxial grain growth during 8YSZ splat formation on polycrystalline YSZ substrates by plasma spraying

Cited by 27 publications

References 36 publications

A solution to the challenges of particle erosion and thermal cycle for PS-PVD 7YSZ thermal barrier coatings

A solution to the challenges of particle erosion and thermal cycle for PS-PVD 7YSZ thermal barrier coatings

Experimental and numerical modeling for flattening and rapid solidification with crystallization behavior of supersonic ceramic droplets

Residual stress and adhesion of thermal spray coatings: Microscopic view by solidification and crystallisation analysis in the epitaxial CoNiCrAlY single splat

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