Laser surface modification of porous yttria stabilized zirconia against CMAS degradation

Bakkar, Said; Pantawane, Mangesh V.; Gu, Jingjing; Ghoshal, Anindya; Walock, Michael J.; Murugan, Muthuvel; Young, Marcus L.; Dahotre, Narendra B.; Berman, Diana; Aouadi, Samir

doi:10.1016/j.ceramint.2019.11.061

Cited by 21 publications

(12 citation statements)

References 23 publications

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“…16 As a result, quick re-solidification within the modified depth introduces a dense layer and a regulated network of segmentation cracks. Researchers 15,[17][18][19][20] reported that hot corrosion and CMAS resistance improves due to laser glazing on the coated surfaces to create a thin dense, and regular structure on the top layer. Zhang et al 17 claimed that the laser-treated TBC showed the longest thermal cycling lifetimes, which was almost 2.5 times longer than that of the as-sprayed coating.…”

Section: Introductionmentioning

confidence: 99%

“…However, they also claimed that following laser glazing, vertical fissures developed that allowed molten salt to seep in and cause corrosion. Bakkar et al 20 discovered that laser treatment suppressed CMAS attacks by acting as a natural barrier. In addition to reducing porosity and heat conductivity, laser treatment enhances inner porosity, which works as a thermal isolation layer.…”

Section: Introductionmentioning

confidence: 99%

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Hot corrosion and CMAS degradation of laser-glazed YSZ coating with optimum parameter

Avcı,

Karabaş,

Akdoğan Eker

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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The purpose of this research is to look into the effect of laser surface modification on the hot corrosion and hot corrosion + calcium–magnesium aluminosilicate (CMAS) resistance of YSZ thermal barrier coating. Metco AMDRY 997 (Ni–22Cr–10Al–Y) powder was coated as a bond coat on the AISI 304L stainless steel substrate using a high-velocity oxy-fuel spray technique. As a ceramic top layer, 204 NS YSZ (ZrO2·8Y2O3) particles were plasma sprayed on the bond coat. Following that, the entire coating surface was treated with a 20-kHz pulsed CO2 laser to increase the coatings’ surface performance. A corrosion test was carried out in a box furnace for 20 h at 1050 °C. SEM images of laser-glazed coatings revealed denser surfaces than those of air-spraying coatings. The laser-modified coating is more resistant to hot corrosion than unmodified coatings. The X-ray diffraction analysis revealed that the reaction between yttria (Y2O3) and V2O5 resulted in the formation of YVO4 crystals as a corrosion product. According to energy dispersive spectroscopy results, laser-glazed coatings reduced molten salt diffusion from surface to bond coat. As a result, laser-glazed coatings demonstrated improved hot corrosion resistance and decreased corrosion products on the bond coat zone. After the hot corrosion test, the laser-treated composite had a 55% lower thermally grown oxide layer than untreated APS YSZ. The optimum laser parameter was used as 77.7 W laser power, 120 mm/s scanning speed, and 215 mm laser distance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hot corrosion and CMAS degradation of laser-glazed YSZ coating with optimum parameter

Avcı,

Karabaş,

Akdoğan Eker

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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“…Recently, pores of the TBC were tailored via Al 2 O 3 –sol impregnation technique, the authors sought to reduce/block the paths of the cracks and pores to mitigate the CMAS infiltration 38 . One of the effective post‐treatment methods is sealing the top surface physically using laser surface modification 33 . Another study on laser treatment to the top coat of the TBC using ND:YAG pulsed laser succeeded to reduce the surface roughness and eliminate the surface porosity but produce a network of cracks 39 …”

Section: Introductionmentioning

confidence: 99%

A new approach to protect and extend longevity of the thermal barrier coating by an impermeable layer of silicon nitride

Bakkar,

Zucha,

Beam

et al. 2023

J Am Ceram Soc.

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A sample representation of a gas turbine engine blade, consisting of a nickel superalloy substrate with a deposited thermal barrier coating (TBC), was covered with silicon nitride, Si 3 N 4 , as an impermeable layer using plasma enhanced chemical vapor deposition (PECVD). The silicon nitride layer was used to seal the topcoat of yttria-stabilized zirconia (YSZ) surface of the TBC to mitigate calciummagnesium-aluminum-silicon oxide (CMAS) attack. CMAS testing was carried out on the covered and uncovered surfaces by melting a ratio of 25 mg/cm 2 of CMAS powder onto the surface of each sample in a furnace at 1100 • C for 1 h. The conformal surface reaction of the sealed layer confirmed no cracking or delamination at high temperatures. Scanning electron microscopy (SEM) micrographs confirmed that the surface of YSZ was successfully sealed. The new coating of silicon nitride was shown to be a viable solution and technique to significantly block CMAS infiltration in porous thermal barrier coatings.

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“…that may be ingested by an engine. These molten silicates, commonly referred to as CMAS (calcium-magnesium-aluminum-silicate), cause severe degradation of TBCs and premature delamination, exposing the metallic components to dangerous hot gases [1,2,3] .…”

Section: Introductionmentioning

confidence: 99%

Reaction products of Sm2Zr2O7 with calcium-magnesium- aluminum-silicate (CMAS) and their evolution

Wang

Liu

et al. 2021

Preprint

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During flight, many silicates (sand, dust, debris, fly ash, etc.) are ingested by an engine. They melt at high operating temperatures on the surface of Thermal barrier coatings (TBCs) to form calcium-magnesium-aluminum-silicate (CMAS) amorphous settling. CMAS erodes TBCs and causes many problems, such as composition segregation, degradation, cracking, and disbanding. As a new generation of TBC candidate materials, rare-earth zirconates (Sm2Zr2O7) have good CMAS resistance properties. The reaction products of Sm2Zr2O7 and CMAS and their subsequent changes were studied by the reaction of Sm2Zr2O7 and excess CMAS at 1350°C. After 1 h of reaction, Sm2Zr2O7 powders were not completely eroded. The reaction products were Sm-apatite and c-ZrO2 solutions. After 4 h of reaction, all Sm2Zr2O7 powders were completely eroded. After 24 h of reaction, Sm-apatite disappeared, and the c-ZrO2 solution remained.

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Laser surface modification of porous yttria stabilized zirconia against CMAS degradation

Cited by 21 publications

References 23 publications

Hot corrosion and CMAS degradation of laser-glazed YSZ coating with optimum parameter

Hot corrosion and CMAS degradation of laser-glazed YSZ coating with optimum parameter

A new approach to protect and extend longevity of the thermal barrier coating by an impermeable layer of silicon nitride

Reaction products of Sm2Zr2O7 with calcium-magnesium- aluminum-silicate (CMAS) and their evolution

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