Optical properties and radiation stability of thermal control coatings based on doped zirconium dioxide powders

2004 ◽  
Vol 19 (2) ◽  
pp. 535-541 ◽  
Author(s):  
M.M. Mikhailov ◽  
A.S. Verevkin
Keyword(s):  
Electromagnetic Radiation ◽  
Zirconium Dioxide ◽  
Diffuse Reflectance ◽  
Satellite Orbit ◽  
Thermal Control ◽  
Radiation Stability ◽  
Simultaneous Action ◽  
Solar Absorptance ◽  
Trivalent Cations ◽  
Thermal Control Coatings

The effect of the doping by compounds with bivalent and trivalent cations (BN, Al2O3, MgO + SiO2) on the diffuse reflectance spectra (ρλ) and the integral solar absorptance (as) and their changes at irradiation (with 30 keV electrons, 3 keV protons, and electromagnetic radiation that imitates solar spectra) of the reflecting thermal control coatings based on ZrO2 powders is examined. The coating based on untreated ZrO2 pigment and the coatings based on the pigments treated with 1 and 3 mass% of Al2O3 nanopowder were subjected to simultaneous action of electrons, protons, and electromagnetic radiation that imitates action of these irradiations on geostationary satellite orbit. After that, the comparative investigations of the changes in spectral reflectance and solar absorptance of these coatings were carried out.

On the Radiation Stability of BaSO4 Pigment Modified with SiO2 Nanoparticles and Applied for Spacecraft Thermal Control Coatings

2018 ◽  
Vol 386 ◽  
pp. 277-282 ◽  
Author(s):  
Mikhail M. Mikhailov ◽  
Vitaly V. Neshchimenko ◽  
Semyon A. Yuryev ◽  
Anatoly V. Grigorevsky ◽  
Alexey A. Lovitskiy ◽  
...  
Keyword(s):  
Thermal Control ◽  
Radiation Stability ◽  
Maximum Effect ◽  
Nanoparticle Concentration ◽  
Absorption Bands ◽  
Near Ir ◽  
Uv Visible ◽  
Thermal Control Coatings ◽  
Spacecraft Thermal Control ◽  
High Temperature Modification

The authors investigated the effect of a high-temperature modification with SiO2 nanoparticles on the optical properties and radiation stability of BaSO4 powders. The modification leads to insignificant alteration in the reflecting capacity within the UV, visible, and near-IR spectral regions. Appending SiO2 nanoparticles with a concentration of up to 10 wt.% results in the increasing radiation stability of BaSO4 powders. The maximum effect was obtained due to the decreasing intensity of the absorption bands at 270-280, 375-395, 440-460, 500-600, 700, and 950 nm at a nanoparticle concentration of 3 wt.%.

Optical Absorption Properties of Nanotitanium Dioxide Doped ZnO/Silicone Thermal Control Coating

2007 ◽  
Vol 546-549 ◽  
pp. 1725-1728
Author(s):  
Wei Qin ◽  
Xiao Hong Wu ◽  
Gui Mei Zhao ◽  
Xiao Ming Lai ◽  
Li Gong Zhang
Keyword(s):  
Optical Properties ◽  
Visible Region ◽  
Wavelength Region ◽  
Thermal Control ◽  
Infrared Region ◽  
Absorption Properties ◽  
Solar Absorptance ◽  
Doped Zno ◽  
Thermal Control Coatings ◽  
Control Principle

As a kind of white paint, ZnO/silicone thermal control coatings are used commonly in space. In order to implement more effective thermal control in space, nanotitanium dioxide was doped to the coatings. In this paper, different percent of nanotitanium dioxide was appended to the coatings, and thermal control principle was discussed. Optical properties of these coatings were discussed by spectrophotometry and infrared reflectometer. The experimental results show that solar absorptance (αs) of nanotitanium dioxide doped ZnO/silicone thermal control coating is lower in all wavelength region than the coatings without doping, especially in visible region and infrared region. The total solar absorptance of 1% nanotitanium dioxide doped coating is 0.09, which decreases by 36% than the undoped coating..

White Anodic Coatings on Aluminum Alloy with Low Ratio of Solar Absorptance to Infrared Emittance

2007 ◽  
Vol 336-338 ◽  
pp. 643-646
Author(s):  
Wei Qin ◽  
Bo Cui ◽  
Xiao Hong Wu ◽  
Zhao Hua Jiang
Keyword(s):  
Optical Properties ◽  
Aluminum Alloy ◽  
Low Cost ◽  
Thermal Control ◽  
Space Environment ◽  
Space Applications ◽  
Solar Absorptance ◽  
Thermal Control System ◽  
Thermal Control Coatings

White anodic coatings are gained by growth in situ on the aluminum alloy. The coatings possess stable optical properties, excellent adhesive power, low cost, stability in the space environment, and so on, which can be widely used in the thermal control system of spacecrafts. In this article, the developed Al2O3 thermal control coatings that had a low solar absorptance and a high infrared emittance were gained in the electrolyte of sulfuric acid. The influences of various process parameters, such as electrolyte temperature, current density, anodizing time, on the optical properties of the coatings were investigated. AFM and XRD were used to characterize the microstructure of the coatings. Experimental results show the anodic coatings could reach a solar absorptance value lower than 0.20 and an infrared emittance higher than 0.80. Therefore, the coatings can be applied as important thermal control coatings for space applications.

Black Anodized Thermal Control Coating on LY12 Aluminum Alloy

2011 ◽  
Vol 233-235 ◽  
pp. 2166-2171 ◽  
Author(s):  
Mei Yu ◽  
Wu Jiang ◽  
Jian Hua Liu ◽  
Song Mei Li
Keyword(s):  
Aluminum Alloy ◽  
Oxide Film ◽  
Thermal Control ◽  
Anodic Oxide ◽  
Open Circuit ◽  
Anodic Oxide Film ◽  
Solar Absorptance ◽  
Porous Oxide ◽  
Thermal Control Coatings ◽  
Galvanostatic Conditions

The black thermal control coatings were prepared by etching anodic oxide film and coloring with an organic ATT dyestuff on the LY12 aluminum alloy. The anodic oxide film on aluminum alloy was formulated in 20% aqueous solution of sulfuric acid in galvanostatic conditions. The microstructure of the anodized coating was studied by scanning electronic microscope (SEM). Open circuit potential (OCP) was applied to study the etching of porous oxide layers in the immerging acid solution. The influence of coloring on the optical properties of the coating was investigated. Results showed that the solar absorptance and infrared emittance increased by increasing coloring times.

Synthesis of nano-porous ZNO as pigment for white silicone thermal control coating and investigation of structure, optical and thermal properties

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vahid Heydari ◽  
Zaker Bahreini ◽  
Majid Abdouss
Keyword(s):  
Near Infrared ◽  
Uv Light ◽  
Thermal Control ◽  
Ideal Condition ◽  
Solar Absorptance ◽  
Content Type ◽  
Scattering Coefficients ◽  
Oxide Particles ◽  
Thermal Control Coatings ◽  
First Time

Purpose The harsh environment of space, especially radiation of direct solar rays, can potentially raise the temperature of the spacecraft to harmful levels. Thermal control coatings (TCCs) fix the thermal condition of the spacecraft acceptable for its components. This is possible by diffusely reflecting all effective ultraviolet (UV), visible (VIS) and near infrared (IR) (NIR) wavelengths of solar radiation and emmition of IR energy. The most commonly used TCCs have used ZnO as a pigment, but absorption of the UV light by ZnO pigment can change the ideal condition of these TCCs. The aim of his study is the using the porous ZnO particles as pigment to prevent the UV absorption. Design/methodology/approach To enhance the efficiency of these coatings, in the present study, nano-porous zinc oxide particles were synthesized and used as pigments for white TCCs. Findings The results revealed that the proposed TCC (TPZ), Thermal control coating with porous ZnO had better reflection (scattering) and emittance properties in comparison with the coating using ZnO as a pigment (TZ coating); so this coating had a solar absorptance value equal to 0.141, whereas this value for TZ was 0.150. Furthermore, TPZ showed higher thermal emittance (0.937) in comparison with TZ (0.9). These changes were because of the improvement in the refractive index, shape and surface area of the pigments. The general trend of the scattering coefficients for the prepared coating, as calculated from the Kubelka–Munk equation, showed that scattering was more efficient in the UV region, as compared with the TCC containing ZnO pigments. Originality/value This type of pigment for the first time is evaluated in TCCs.

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