Structure, optical properties and thermal stability of Al2O3-WC nanocomposite ceramic spectrally selective solar absorbers

Gao, Xiang‐Hu; Wang, Cheng-Bing; Guo, Zhi-Ming; Geng, Qin; Theiß, W.; Liu, Gang

doi:10.1016/j.optmat.2016.05.037

Cited by 30 publications

(6 citation statements)

References 22 publications

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“…These noticeable changes are due to the strong absorption of the incident, scattered by the nanotube laser radiation by a pyrolytic tungsten carbide coating layer and the uncoated nanotube surface area decrease. The penetration depth of the exciting laser light into the WC and WC 1-x coating could roughly be estimated to a 30-80 nm [48][49][50]. In doing so, the penetration depth into the amorphous and crystalline WO 3 films is very high, because all the films are transparent above λ = 400 nm [51].…”

Section: Raman Spectra Of the Nanocomposites And Initial Mwcntsmentioning

confidence: 99%

Studies of Buried Layers and Interfaces of Tungsten Carbide Coatings on the MWCNT Surface by XPS and NEXAFS Spectroscopy

et al. 2020

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Currently, X-ray photoelectron spectroscopy (XPS) is widely used to characterize the nanostructured material surface. The ability to determine the atom distribution and chemical state with depth without the sample destruction is important for studying the internal structure of the coating layer several nanometers thick, and makes XPS the preferable tool for the non-destructive testing of nanostructured systems. In this work, ultra-soft X-ray spectroscopy methods are used to study hidden layers and interfaces of pyrolytic tungsten carbide nanoscale coatings on the multi-walled carbon nanotube (MWCNT) surfaces. XPS measurements were performed using laboratory spectrometers with sample charge compensation, and Near Edge X-ray Absorption Fine Structure (NEXAFS) studies using the Russian–German dipole beamline (RGBL) synchrotron radiation at BESSY-II. The studied samples were tested by scanning and transmission electron microscopy, X-ray diffractometry, Raman scattering and NEXAFS spectroscopy. It was shown that the interface between MWCNT and the pyrolytic coating of tungsten carbide has a three-layer structure: (i) an interface layer consisting of the outer graphene layer carbon atoms, forming bonds with oxygen atoms from the oxides adsorbed on the MWCNT surface, and tungsten atoms from the coating layer; (ii) a non-stoichiometric tungsten carbide WC1-x nanoscale particles layer; (iii) a 3.3 nm thick non-stoichiometric tungsten oxide WO3-x layer on the WC1-x/MWCNT nanocomposite outer surface, formed in air. The tungsten carbide nanosized particle’s adhesion to the nanotube outer surface is ensured by the formation of a chemical bond between the carbon atoms from the MWCNT upper layer and the tungsten atoms from the coating layer.

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Section: Raman Spectra Of the Nanocomposites And Initial Mwcntsmentioning

confidence: 99%

Studies of Buried Layers and Interfaces of Tungsten Carbide Coatings on the MWCNT Surface by XPS and NEXAFS Spectroscopy

et al. 2020

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“…The surface structure of the coatings became denser with increasing annealing time. The increased rms roughness enhances the diffuse reflectance and decreases the transmittance . In brief, no significant changes were observed in the surface morphology of the coating, indicating excellent thermal stability of the films annealed at 50 °C for different durations (a high maximum transmittance of 71.8% and a reflectance of 88.5%).…”

Section: Resultsmentioning

confidence: 96%

SiN_x/Cu Spectral Beam Splitting Films for Hybrid Photovoltaic and Concentrating Solar Thermal Systems

et al. 2021

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Spectral beam splitting (SBS) films are crucial for the development of hybrid systems based on photovoltaic (PV) and concentrating solar thermal (CST) technologies. In this study, a novel double-layer SiN x /Cu SBS film was prepared via magnetron sputtering. This film was developed based on the linear Fresnel solar thermal technology used in PV/CST hybrid systems. The as-deposited film exhibited superior SBS properties, with a high transmittance of 72.9% and a reflectance of 89.7%. To optimize the optical properties, the thicknesses of the metal and SiN x layers were precisely controlled. The optimal thicknesses of the Cu and SiN x layers were determined to be 17 and 67 nm, respectively. Furthermore, the thermal stability of the SBS film was evaluated. When annealed at 50 °C, the surface of the SBS film became more uniform and smooth, and with increasing annealing time, the film became denser. No strong diffraction peaks of Cu were observed in the X-ray diffraction patterns because of the low content and poor crystallization of Cu. Atomic force microscopy investigations revealed the formation of a textured surface and a decrease in the root-mean-square roughness with an increase in the annealing time from 0 to 360 h. As a key component with considerable application potential in PV/CST hybrid systems, SBS films are currently an important research topic.

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“…6,7 Due to their refractivity, inherent partial spectral selectivity, and high thermal stability, transition metal-based ceramics are being explored as prospective SSAC materials. [8][9][10][11] When used in the multilayer design, these compounds demonstrate enhanced optical properties with good thermal stability. 12,13 The thickness and optical constants, like refractive index (n) and extinction coefficient (k) of the individual layers, are the factors that determine the absorptance in multilayer absorber coatings.…”

Section: Introductionmentioning

confidence: 99%

Angular absorptance and thermal degradation analysis of TiB₂/Ti(B,N)/SiON/SiO₂ multilayer solar absorber coating

et al. 2022

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Multilayer solar selective absorber coatings have been developed in the last few decades. The thermal stability in terms of microstructure gives an insightful understanding of the optical properties of such coatings. In this context, we extensively utilized transmission electron microscopy (TEM) analysis to establish the thermal stability of TiB 2 /Ti(B,N)/SiON/SiO 2 coating, under thermal cycling/continuous heating to 500 • C in vacuum for 250 h. In particular, this work reports the variation in the solar absorptance of TiB 2 /Ti(B,N)/SiON/SiO 2 coating with different angles of incidence of the solar radiation. Extensive analysis using the TEM technique reveals the presence of oxide interlayers that act as diffusion barrier layers to enhance the thermal stability of the coating.Computational simulation using SCOUT software validates the measured reflectance spectrum of the developed multilayer coating. The minor changes in absorptance and emissivity after heat treatment in vacuum at 500 • C, together with high solar absorptance over a broad angular variation, establish the potential application of TiB 2 /Ti(B,N)/SiON/SiO 2 as a selective coating in concentrated solar power systems.

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Structure, optical properties and thermal stability of Al2O3-WC nanocomposite ceramic spectrally selective solar absorbers

Cited by 30 publications

References 22 publications

Studies of Buried Layers and Interfaces of Tungsten Carbide Coatings on the MWCNT Surface by XPS and NEXAFS Spectroscopy

Studies of Buried Layers and Interfaces of Tungsten Carbide Coatings on the MWCNT Surface by XPS and NEXAFS Spectroscopy

SiN_x/Cu Spectral Beam Splitting Films for Hybrid Photovoltaic and Concentrating Solar Thermal Systems

Angular absorptance and thermal degradation analysis of TiB₂/Ti(B,N)/SiON/SiO₂ multilayer solar absorber coating

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Structure, optical properties and thermal stability of Al2O3-WC nanocomposite ceramic spectrally selective solar absorbers

Cited by 30 publications

References 22 publications

Studies of Buried Layers and Interfaces of Tungsten Carbide Coatings on the MWCNT Surface by XPS and NEXAFS Spectroscopy

Studies of Buried Layers and Interfaces of Tungsten Carbide Coatings on the MWCNT Surface by XPS and NEXAFS Spectroscopy

SiNx/Cu Spectral Beam Splitting Films for Hybrid Photovoltaic and Concentrating Solar Thermal Systems

Angular absorptance and thermal degradation analysis of TiB2/Ti(B,N)/SiON/SiO2 multilayer solar absorber coating

Contact Info

Product

Resources

About

SiN_x/Cu Spectral Beam Splitting Films for Hybrid Photovoltaic and Concentrating Solar Thermal Systems

Angular absorptance and thermal degradation analysis of TiB₂/Ti(B,N)/SiON/SiO₂ multilayer solar absorber coating