Microstructure and spectral selectivity of Mo–Al2O3 solar selective absorbing coatings after annealing

Du, Xiaodong; Wang, Wenwen; Wang, Tianmin; Zhang, Long; Chen, Buliang; Ru, Ning

doi:10.1016/j.tsf.2007.07.193

Cited by 78 publications

(30 citation statements)

References 19 publications

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“…The ε therm was calculated by Eq. 2, on the Planck blackbody distribution at 100 °C, as shown in Table 1 previous studies, the ε therm of this study was lower than the Pt-Al 2 O 3 coating (ε therm = 0.36) [23] and close to the Ni-Al 2 O 3 coatings (ε therm = 0.14-0.23) [21] and Mo-Al 2 O 3 coating (ε therm = 0.19-0.27) [24]. As the results shown in Fig.…”

Section: Instrumentationsupporting

confidence: 70%

Influence of tin content on spectral selectivity and thermal conductivity of Sn–Al2O3 solar selective absorber

Wamae

Suriwong

Threrujirapapong

2018

Mater Renew Sustain Energy

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The tin-pigmented aluminium oxide film (Sn-Al 2 O 3 ) based solar selective absorber was successfully prepared with three different contents of tin by an anodization process. The phase and morphology of the Sn-Al 2 O 3 were measured by X-ray diffractometer and a scanning electron microscope equipped with an energy dispersive X-ray analyser. The reflectance (R) of the coating was determined by Ultraviolet-visible-near infrared spectrophotometer in the wavelength interval of 300-2500 nm and the Fourier transform infrared spectrophotometer in the wavelength of infrared region (2500-25,000 nm). As a result, aluminium and tin phases were detected at the coating surface. The Al 2 O 3 films were formed and compacted as a barrier on the Al substrate. The compositions of the oxide film composed of tin (Sn), aluminium (Al) and oxygen (O) elements. With increasing Sn content, the solar absorptance (α sol ) gradually increased, but it has little effect on the thermal emittance (ε therm ). The thermal conductivity of Sn-Al 2 O 3 samples decreased with increasing Sn content as a result of the increasing thickness of the Sn layer at the interface leading to obstruct the free electrons and phonon contributions. The present result suggests that the increasing Sn content in the Sn-Al 2 O 3 coating can enhance the solar selectivity properties and a good solar absorber material.

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Section: Instrumentationsupporting

confidence: 70%

Influence of tin content on spectral selectivity and thermal conductivity of Sn–Al2O3 solar selective absorber

Wamae

Suriwong

Threrujirapapong

2018

Mater Renew Sustain Energy

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“…The absorption of solar radiation in the cermet layer is mostly caused by interband transitions in the [5,6,[7][8][9] They all have ceramic host materials in common that naturally possess high temperature stability. The metal filler atoms must be chosen for their high melting point and their nitriding and oxidation resistance to ensure thermal stability.…”

Section: Introductionmentioning

confidence: 99%

“…For example, MoAl 2 O 3 cermet coatings deposited on stainless steel (SS) are proven to be stable at 800 °C for 2 hrs in vacuum. [9] Antonaia et al replaced Mo with W and found a slight change in the reflection spectra after annealing at 580 o C for 2 days in vacuum. [8] Mo-SiO 2 cermet based solar spectrally selective absorbers deposited on SS also displayed a high solar absorptance of 0.94 and a very low thermal emittance at 580 o C. [11] Bare copper and aluminum are excluded as substrate material for high temperature solar absorbers due to the low melting point of aluminum and the high elemental diffusion of copper atoms at high temperature.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Thermal Stability of W‐Ni‐Al₂O₃ Cermet‐Based Spectrally Selective Solar Absorbers with Tungsten Infrared Reflectors

Cao

Kraemer

Sun

et al. 2014

Advanced Energy Materials

154

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Solar thermal technologies such as solar hot water and concentrated solar power trough systems rely on spectrally-selective solar absorbers. These solar absorbers are designed to efficiently absorb the sunlight while suppressing re-emission of infrared radiation at elevated temperatures. Efforts for the development of such solar absorbers must not only be devoted to their spectral selectivity but also to their thermal stability for high temperature applications. In this work selective solar absorbers based on two cermet layers are fabricated using a magnetron sputtering technique on mechanically 2 polished stainless steel substrates. The targeted operating temperature is 500 -600 °C. However, we observed a detrimental change in the morphology, phase, and optical properties if the cermet layers are deposited on a stainless steel substrate with a thin nickel adhesion layer, which is due to the diffusion of iron atoms from the stainless steel into the cermet layer forming a FeWO 4 phase. In order to improve thermal stability and reduce the infrared emittance, we find tungsten to be a good candidate for the infrared reflector layer due to its excellent thermal stability and low infrared emittance. We demonstrate a stable solar absorptance of ~0.90 and total hemispherical emittance of 0.15 at 500 °C.

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“…Du et al [52] designed a new solar selective coating, Ti 0.5 Al 0.5 N and Ti 0.25 Al 0.75 N coatings were chosen as absorber layers, and AlN coating was chosen as anti-reflecting layer and calculated the absorptance 0.945 and low emittance 0.04 (82°C) of the solar selective coating. Xinkang et al [53] prepared a series of Mo-Al 2 O 3 films by direct current (DC, for metal Mo) and radio frequency (RF, for dielectric Al 2 O 3 ) magnetron sputtering techniques and evaluated thermal stability at different temperatures and also investigated the variation of microstructure, diffusion of the component, and influences on the spectral performances. Vien et al [54] reported features of Pt--Al 2 O 3 cermet coatings which is deposited by RF cosputtering on metallic substrate and obtained absorptivity α = 0.92, emissivity ε = 0.14 (at 300°C), and also obtained the stability of selective absorbers at a temperature of up to 400°C when cermet coating is deposited on stainless steel substrate and over 600°C on superalloy substrate.…”

Section: Solar Spectral Selective Mechanismsmentioning

confidence: 99%

High-Temperature Solar Selective Coating

Usmani

Harinipriya

2015

Lecture Notes in Electrical Engineering

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Solar energy has maximum potential in comparison with other renewable energy sources. Solar thermal conversion is one of the direct methods for harnessing solar energy using solar selective absorbers. This review article summarizes the recent research progress on the high-temperature solar selective coatings, methodology, and process involved in coating, computer modeling, as well as designs of coatings, optical, compositional, and structural properties of selective coatings. The major bottleneck in developing a solar selective coating is its stability in air at temperature higher than 450°C that possess thermal and structural stability in both individual and combined layers. New possibilities to overcome the abovementioned problems on the performance of solar selective coatings are discussed.

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Microstructure and spectral selectivity of Mo–Al2O3 solar selective absorbing coatings after annealing

Cited by 78 publications

References 19 publications

Influence of tin content on spectral selectivity and thermal conductivity of Sn–Al2O3 solar selective absorber

Influence of tin content on spectral selectivity and thermal conductivity of Sn–Al2O3 solar selective absorber

Enhanced Thermal Stability of W‐Ni‐Al₂O₃ Cermet‐Based Spectrally Selective Solar Absorbers with Tungsten Infrared Reflectors

High-Temperature Solar Selective Coating

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Microstructure and spectral selectivity of Mo–Al2O3 solar selective absorbing coatings after annealing

Cited by 78 publications

References 19 publications

Influence of tin content on spectral selectivity and thermal conductivity of Sn–Al2O3 solar selective absorber

Influence of tin content on spectral selectivity and thermal conductivity of Sn–Al2O3 solar selective absorber

Enhanced Thermal Stability of W‐Ni‐Al2O3 Cermet‐Based Spectrally Selective Solar Absorbers with Tungsten Infrared Reflectors

High-Temperature Solar Selective Coating

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Enhanced Thermal Stability of W‐Ni‐Al₂O₃ Cermet‐Based Spectrally Selective Solar Absorbers with Tungsten Infrared Reflectors