Investigation of the effect of BC layer surface roughness and TC layer porosity on stress values in plasma sprayed coatings based on SEM images

Montakhabi, Farzam; Rahimi, Javad; Sigaroodi, Mohammad Rasoul Javadi

doi:10.1016/j.mtcomm.2022.104737

Cited by 7 publications

(2 citation statements)

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“…It reacts with oxygen permeated through the TC layer, forming a TGO layer at the BC/TC interface. 8,9 Spallation of the TC layer is one of the main reasons for the failure of TBCs. 10,11 This spallation is generally caused by cracks in the TC layer and the TGO/TC interface due to the stresses generated during thermal cycling.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and numerical life evaluation of TBCs with different BC and diffusion coating under cyclic thermal loading

Rahimi

Montakhabi

Sigaroodi

et al. 2023

Int J Applied Ceramic Tech

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This paper experimentally and numerically investigates the thermally grown oxide (TGO), lifetime, and stress values in thermal barrier coatings with different bond coat (BC), without top coat (TC), and diffusion coating under cyclic thermal loading. Scanning electron microscope (SEM) analysis shows that the atmospheric plasma spraying (APS) and high‐velocity oxygen fuel (HVOF) fabricated sample has the highest and lowest TGO thickness and growth rate, respectively. The new coating with two BCs has a maximum lifetime of 102 cycles. After that, the lifetime of the coatings with HVOF‐BC, diffusion coating, and APS‐BC reach 84, 56, and 44 cycles, respectively. The diffusion coating does not have much effect on the TGO thickness; however, it delays the Al interdiffusion to the substrate. In the sample without the TC layer, oxygen contact with the BC layer has increased, leading to a rise in the BC oxidation rate. The numerical analysis of the stress values based on SEM images shows that the more intense TGO layer growth in APS coating caused an increase in TC layer stress values. Furthermore, the results show that the new coating with two‐layer BC has the lowest stress values. The TC absence causes the loss of compressive stresses caused by TC on TGO and increases the tensile stress values in this layer.

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Section: Introductionmentioning

confidence: 99%

“…In a high‐temperature environment, aluminum in the BC layer diffuses toward the BC/TC interface. It reacts with oxygen permeated through the TC layer, forming a TGO layer at the BC/TC interface 8,9 …”

Section: Introductionmentioning

confidence: 99%