Heredity and variation of hollow structure from powders to coatings through atmospheric plasma spraying

Gao, Peihu; Yang, Guan-Jun; Cao, Si-Ting; Li, Jianping; Yang, Zhong; Guo, Yongchun

doi:10.1016/j.surfcoat.2016.08.007

Cited by 27 publications

(12 citation statements)

References 25 publications

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“…The typical splat and lamellar microstructure, some pores, and micro-cracks were also observed in the two as-sprayed coatings. The inherent characteristics of thermal sprayed technology inevitably result in the existence of microstructure defects in the coating [20]. The porosity proportion of the Mo and Al 2 O 3 -Mo coatings, estimated by the image analysis, are about (7.2 ± 0.3)% and (10.2 ± 0.5)%, respectively.…”

Section: Microstructure Of As-sprayed Coatingsmentioning

confidence: 99%

A Comparison Study on Wear Behaviors of Mo and Al2O3-Mo Coatings from RT to 300 °C

et al. 2018

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Mo and Al 2 O 3 -Mo coatings are fabricated on a low-carbon steel substrate using atmospheric plasma spraying. The microstructure and mechanical properties of two as-sprayed coatings, with a particular focus on the tribological behaviors from room temperature to 300 • C, are comparatively investigated in this study. Microstructural analysis of the coatings shows that the porosity of the Al 2 O 3 -Mo coating is higher than that of Mo coating. The addition of Al 2 O 3 particles reduces the coating-substrate adhesion strength. The Al 2 O 3 -Mo coating, in comparison to the Mo coating, shows improved mechanical properties, such as hardness and wear resistance. The friction coefficients of both coatings increase with further increases in test temperatures. The friction coefficient of the Al 2 O 3 -Mo coating, tested above 100 • C, is lower than that of the Mo coating. The wear failure mechanisms of the two coatings are delamination, brittle fracture, oxidation and adhesion wear. In addition, local plastic deformation was also found in the Mo coating.

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Section: Microstructure Of As-sprayed Coatingsmentioning

confidence: 99%

A Comparison Study on Wear Behaviors of Mo and Al2O3-Mo Coatings from RT to 300 °C

et al. 2018

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“…To reduce the thermal conductivity of the TBCs furtherly, large closed pores at microns and tens of microns size are introduced to TBCs through pore-forming agents, such as polypropylene (PP), polymethyl methacrylate (PMMA), high-density polyethylene (HDPE), polyetherether-ketone (PEEK), mesocarbon-microbead (MCMB) carbon powder and so on [16]. Gao et al [17] used hollow spherical powder of YSZ with nano structured shells to prepare multi-sized porous TBCs at nano and micron scale through atmospheric plasma spraying. Masayuki Arai et al [18] used polyester to create large pores at tens of microns scale in TBCs, which had a porosity of about 40% and a very low thermal conductivity of about 0.3 W/m•K at 1100 • C. Therefore, constructed pores will be beneficial to insulate thermal flows.…”

Section: Introductionmentioning

confidence: 99%

Thermal Conductivity of Multi-Sized Porous Thermal Barrier Coatings at Micro and Nano Scales after Long-Term Service at High Temperatures

et al. 2021

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Thermal barrier coatings with multi-sized porous structure at micro and nano scales were prepared with hollow spherical YSZ powders and polypropylene powders through atmospheric plasma spraying. The thermal conductivities of the multi-sized thermal barrier coatings after a long-term serving at high temperature were tested through laser flash heating method. Meanwhile, the physical models of thermal barrier coatings with multi-sized porous structure at micro and nano scales were constructed through Ansys Workbench. The evolutions of thermal conductivity of thermal barrier coatings with multi-sized pores after long-term service at 1100 °C were investigated through computation. It was found that the thermal conductivity of the coating increased with the extension of the serving time. When the serving time reached 60 days, the thermal conductivity of the coating tended to be stable and close to the compacted bulk. The computational results were consistent with the tested ones, which could be helpful to explain the thermal conducting evolution in thermal barrier coatings with multi-sized porous structure at nano and micro scales after long-term serving at high temperature.

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“…The use of co-doped trivalent or pentavalent rare earth oxides into zirconia ceramic materials can change the structure of the thermal barrier coatings [ 15 ]. Rare earth elements have special electronic layer structure and activity, low electronegativity, and special chemical activity [ 16 ]. In addition, rare earth elements have strong adsorption capacity for other elements, high chemical stability, and high melting point, and can be dissolved in a limited solid solution of ZrO 2 .…”

Section: Introductionmentioning

confidence: 99%

Effect of Gd2O3 Addition on the Microstructure and Properties of Gd2O3-Yb2O3-Y2O3-ZrO2 (GYYZO) Ceramics

et al. 2021

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Gd and Yb elements have high chemical stability, which can stabilize the solid solution in ZrO2. Gd2O3 and Yb2O3 have high melting points, and good oxidation resistance in extreme environments, stable chemical properties. Therefore, Gd2O3 and Yb2O3 were added to ZrO2 to stabilize oxides, improve the high temperature stability, and effectively decrease the thermal conductivity at high temperature. In this work, 5 wt% Yb2O3 and 5 wt%, 10 wt%, 15 wt% Gd2O3 were doped into 8 wt% Y2O3 stabilized ZrO2 (8YSZ) powders as thermal barrier coating materials, and sintered at 1650 °C for 6 h, 12 h, 24 h. The effects of Gd2O3 addition on the microstructure, density, thermal conductivity, hardness, and fracture toughness of Gd2O3-Yb2O3-Y2O3-ZrO2 (GYYZO) bulk composite ceramics were investigated. It was found that the densification of the 8YSZ bulk and GYYZO bulk with 15 wt% Gd2O3 reached 96.89% and 96.22% sintered at 1650 °C for 24 h. With the increase of Gd2O3 addition, the hardness, elastic modulus and fracture toughness of the GYYZO bulk increased and the thermal conductivity and thermal expansion coefficient of the GYYZO bulk decreased. GYYZO bulk with 15 wt% Gd2O3 sintered at 1650 °C for 24h had the highest hardness, elastic modulus and fracture toughness of 15.61 GPa, 306.88 GPa, 7.822 MPa·m0.5, and the lowest thermal conductivity and thermal expansion coefficient of 1.04 W/(m·k) and 7.89 × 10−6/°C at 1100 °C, respectively. The addition of Gd2O3 into YSZ could not only effectively reduce the thermal conductivity but also improve the mechanical properties, which would improve the thermal barrier coatings’ performances further.

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Heredity and variation of hollow structure from powders to coatings through atmospheric plasma spraying

Cited by 27 publications

References 25 publications

A Comparison Study on Wear Behaviors of Mo and Al2O3-Mo Coatings from RT to 300 °C

A Comparison Study on Wear Behaviors of Mo and Al2O3-Mo Coatings from RT to 300 °C

Thermal Conductivity of Multi-Sized Porous Thermal Barrier Coatings at Micro and Nano Scales after Long-Term Service at High Temperatures

Effect of Gd2O3 Addition on the Microstructure and Properties of Gd2O3-Yb2O3-Y2O3-ZrO2 (GYYZO) Ceramics

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