Preparation And Properties Of Solar Selective Absorbers Based On AlCuFe AND AlCuFeCr Thin Films: Industrial Aspects

1998 ◽  
Vol 553 ◽  
Author(s):  
T. Eisenhammer ◽  
H. Nolte ◽  
W. Assmann ◽  
J. M. Dubois
Keyword(s):  
Thin Films ◽  
Elevated Temperatures ◽  
Oxidation Stability ◽  
Antireflective Coatings ◽  
Good Adhesion ◽  
Solar Absorptance ◽  
Thermal Emittance ◽  
Energy Applications ◽  
Large Roughness ◽  
Oxidation In Air

AbstractSolar selective absorbers for thermal energy applications can be realized with films of quasicrystal forming alloys. Absorbers were produced by sputtering thin films of AlCuFe and AlCuFeCr. Alumina and floatglass were used as dielectric antireflective coatings, which are necessary for the required optical properties. For applications, several aspects are of importance: high solar absorptance and low thermal emittance have to be achieved. Moreover, the coatings have to show good adhesion and stability with respect to oxidation in air at elevated temperatures and exposure to humidity and condensation of water. The present study emphasizes these aspects, especially degradation stability, for coatings deposited on technical copper foils with large roughness. Oxidation stability is achieved easily, while humidity stability depends strongly on the choice of materials. The combination AlCuFeCr/floatglass turned out to be stable, while the combination AlCuFe/alumina is destroyed rapidly.

Characterization of Pyromark 2500 Paint for High-Temperature Solar Receivers

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Clifford K. Ho ◽  
A. Roderick Mahoney ◽  
Andrea Ambrosini ◽  
Marlene Bencomo ◽  
Aaron Hall ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Normal Incidence ◽  
Radiative Properties ◽  
Solar Absorptance ◽  
Thermal Emittance ◽  
Percentage Points ◽  
Original Coating

Pyromark 2500 is a silicone-based high-temperature paint that has been used on central receivers to increase solar absorptance. The radiative properties, aging, and selective absorber efficiency of Pyromark 2500 are presented in this paper for use as a baseline for comparison to high-temperature solar selective absorber coatings currently being developed. The solar absorptance ranged from ∼0.97 at near-normal incidence angles to ∼0.8 at glancing (80°) incidence angles, and the thermal emittance ranged from ∼0.8 at 100 °C to ∼0.9 at 1000 °C. After thermal aging at temperatures of ∼750 °C or higher, the solar absorptance decreased by several percentage points within a few days. It was postulated that the substrate may have contributed to a change in the crystal structure of the original coating at elevated temperatures.

Analysis of Tungsten-Alumina Nanocomposite Thin Films on SS304 Substrate

2021 ◽  
Vol 903 ◽  
pp. 125-132
Author(s):  
T.R. Mohan Kumar ◽  
P.V. Srihari ◽  
Sahas ◽  
M.S. Krupashankara
Keyword(s):  
Thin Films ◽  
Process Parameters ◽  
Gas Flow ◽  
Composite Coatings ◽  
Research Work ◽  
Substrate Material ◽  
Key Factors ◽  
Solar Absorptance ◽  
Thermal Emittance ◽  
Deposition Parameters

Higher solar absorptance and lower thermal emittance are the key factors for solar collectors. The use of thin films that are having mechanically resistant coatings are common practice in industries. The primary motivation of carrying this research work is to lower thermal emittance and maximize solar absorptance on SS304 substrate material. W-Al2O3 composite coatings are developed using magnetron sputtering process by considering the process parameters. The experimental plan is achieved based on Taguchi L9 orthogonal under various levels for deposition parameters. The tungsten and alumina thin films deposited using a co-sputtering were characterized using 410 - solar instrument for measuring solar absorptance and ET 100 Emissometer for measuring thermal emittance. The optimization for process parameters on thermal emittance and absorptance were carried out. It was found that for deposition parameters of DC power 750W, RF power 1050W and Argon gas flow rate of 250 sccm, absorptance of 0.758 with thermal emittance of 0.061 is observed with deposition was carried out on SS304 substrates.

Preferential Orientation of Photochromic Gadolinium Oxyhydrides

2020 ◽  
Author(s):  
Elbruz Murat Baba ◽  
Jose Montero ◽  
Dmitrii Moldarev ◽  
Marcos V. Moro ◽  
Max Wolff ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Rare Earth ◽  
Preferential Orientation ◽  
Reactive Magnetron ◽  
Flow Ratio ◽  
Deposition Pressure ◽  
Step Process ◽  
Oxidation In Air ◽  
Key Parameter

<p>We report preferential orientation control in photochromic gadolinium oxyhydride (GdHO) thin films deposited by a two-step process. Gadolinium hydride (GdH<sub>2-x</sub>) films were grown by reactive magnetron sputtering, followed by oxidation in air. The preferential orientation, grain size, anion concentrations, and photochromic response of the films are strongly dependent on the deposition pressure. GdHO films show preferential orientation along the [100] direction and exhibit photochromism when synthesized at deposition pressures up to 5.8 Pa and. The photochromic contrast is larger than 20 % when the films are deposited below 2.8 Pa with 0.22 H<sub>2</sub>/Ar flow ratio. We argue that the degree of preferential orientation defines the oxygen concentration which is known to be a key parameter for photochromism in rare-earth oxyhydride thin films. The experimental observations described above are explained by the oxidation-induced decrease of the grain size as a result of the increase of the deposition pressure of the sputtering gas. </p>

scholarly journals Thermal emittance and solar absorptance measurement comparison on receiver tube absorber samples

2020 ◽  
Author(s):  
Fabienne Sallaberry ◽  
Javier Barriga ◽  
Alberto García de Jalón ◽  
Francisco Goñi ◽  
Raquel Erice ◽  
...  
Keyword(s):  
Solar Absorptance ◽  
Thermal Emittance

scholarly journals Influence of Heterointerfaces on the Kinetics of Oxygen Surface Exchange on Epitaxial La1.85Sr0.15CuO4 Thin Films

2021 ◽  
Vol 11 (9) ◽  
pp. 3778
Author(s):  
Gene Yang ◽  
So-Yeun Kim ◽  
Changhee Sohn ◽  
Jong K. Keum ◽  
Dongkyu Lee
Keyword(s):  
Thin Films ◽  
Oxygen Vacancies ◽  
Elevated Temperatures ◽  
Surface Exchange ◽  
Electrical Conductivity Relaxation ◽  
Exchange Kinetics ◽  
Relaxation Curves ◽  
Kinetics Of ◽  
Oxygen Surface Exchange ◽  
Oxygen Surface

Considerable attention has been directed to understanding the influence of heterointerfaces between Ruddlesden–Popper (RP) phases and ABO3 perovskites on the kinetics of oxygen electrocatalysis at elevated temperatures. Here, we report the effect of heterointerfaces on the oxygen surface exchange kinetics by employing heteroepitaxial oxide thin films formed by decorating LaNiO3 (LNO) on La1.85Sr0.15CuO4 (LSCO) thin films. Regardless of LNO decoration, tensile in-plane strain on LSCO films does not change. The oxygen surface exchange coefficients (kchem) of LSCO films extracted from electrical conductivity relaxation curves significantly increase with partial decorations of LNO, whereas full LNO coverage leads to the reduction in the kchem of LSCO films. The activation energy for oxygen exchange in LSCO films significantly decreases with partial LNO decorations in contrast with the full coverage of LNO. Optical spectroscopy reveals the increased oxygen vacancies in the partially covered LSCO films relative to the undecorated LSCO film. We attribute the enhanced oxygen surface exchange kinetics of LSCO to the increased oxygen vacancies by creating the heterointerface between LSCO and LNO.

Tensile and fatigue behavior of polymer supported silver thin films at elevated temperatures

2017 ◽  
Vol 193 ◽  
pp. 81-84 ◽  
Author(s):  
Yong-Seok Lee ◽  
Gi-Dong Sim ◽  
Jong-Soo Bae ◽  
Ji-Young Kim ◽  
Soon-Bok Lee
Keyword(s):  
Thin Films ◽  
Elevated Temperatures ◽  
Fatigue Behavior ◽  
Polymer Supported ◽  
Silver Thin Films

Transmission Electron Microscope Investigation of Sputtered Co-Pt Thin Films

1985 ◽  
Vol 48 ◽  
Author(s):  
P. Alexopoulos ◽  
R. H. Geiss ◽  
M. Schlenker
Keyword(s):  
Thin Films ◽  
Elevated Temperatures ◽  
Hexagonal Phase ◽  
Substantial Reduction ◽  
Magnetic Domain ◽  
Dark Field ◽  
Carbon Substrate ◽  
Dark Field Imaging ◽  
Carbon Substrates ◽  
Carbon Coated

ABSTRACTThin films of Co-10 at% Pt, ranging from 15 to 90 nm in thickness, have been DC-sputtered at various temperatures on to carbon-coated mica, carbon substrates on copper grids, or (001) silicon single crystals under 3 μm pressure of Ar, using targets of the alloy in the hexagonal phase, at growth rates of 9 nm/min. The samples were investigated by TEM, using bright-and dark-field imaging, lattice imaging, selected area diffraction and both Fresnel and focussed Lorentz modes. The primary structure of the films was found to be hexagonal, with a = 0.255 nm and c = 0.414 nm. For the samples sputtered at room temperature, the grain sizes were on the order of 0.μm on carbon-coated mica and carbon-substrate grids, and approximately an order of magnitude smaller on silicon substrates. Heavy streaking along the [001] of the hexagonal matrix was observed on diffraction patterns for grains having the [001] parallel to the surface; this streaking was found to be associated with the presence of a high density of faults parallel to the (001). In films sputtered on to carbon-coated mica at 225 °C, where a substantial reduction of the coercivity is observed, the overwhelming majority of the grains had the (001) basal plane parallel to the surface. Lorentz microscopy showed the magnetic domain structure in films grown on silicon to be markedly different from those grown on the carbon substrates, and further changes occurred for the films grown at elevated temperatures.

Development of the Structural, Optical, and Electrical Properties of PEDOT:PSS Conducting Polymer Thin Film for Energy Applications

2021 ◽  
Vol 902 ◽  
pp. 65-70
Author(s):  
Samar Aboulhadeed ◽  
Mohsen Ghali ◽  
Mohamad M. Ayad
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electrical Properties ◽  
Conducting Polymer ◽  
Film Surface ◽  
Volume Ratio ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Optical And Electrical Properties ◽  
Energy Applications

We report on a development of the structural, optical and electrical properties of poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT:PSS) conducting polymer thin films. The PEDOT:PSS thin films were deposited by a controlled thin film applicator and their physical properties were found to be effectively modified by isopropanol. The deposited films were investigated by several techniques including XRD, UV–Vis, SPM and Hall-effect. Interestingly, by optimizing the PEDOTS:PSS/ISO volume ratio (v:v), we find that the film charge carriers type can be switched from p to n-type with a high bulk carriers concentration reaching 6×1017 cm-3. Moreover, the film surface roughness becomes smoother and reaching a small value of only 1.9 nm. Such development of the PEDOT:PSS film properties makes it very promising to act as an electron transport layer for different energy applications.

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