Thermal control film with controllable emissivity

A technology of thermal control thin film and emissivity, which is applied in the field of aerospace materials, can solve the problems that the thermal control performance cannot be changed, and achieve the effects of good space environment stability, improved resistance to space radiation, and convenient manufacturing

Inactive Publication Date: 2017-06-06
LANZHOU INST OF PHYSICS CHINESE ACADEMY OF SPACE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its common limitation is that the performance of each thermal control film is fixed, and its thermal control performance cannot be changed by adjusting the composition or thickness of each film layer.

Method used

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  • Thermal control film with controllable emissivity
  • Thermal control film with controllable emissivity
  • Thermal control film with controllable emissivity

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] A thermal control thin film with controllable emissivity, the substrate is polyimide, on the surface of the substrate from inside to outside is a 150nm thick silver film, 1.9μm thick Al 2 o 3 layer and a 400nm thick SiO 2 layer, structured as figure 1 shown. The solar absorptivity of the film was 0.13.

[0048] The reflectance spectrum of the thermal control film at a wavelength of 200-20000nm and the 300K black body radiation intensity curve are shown in image 3 . It can be seen from the figure that the film has a high solar absorption rate in the thermal infrared region of 8-13 μm), and the peak radiation intensity of the 300K black body is in this band, which indicates that the prepared thermal control film has a high thermal emissivity. The calculated hemispherical emissivity of the film is 0.59, and the hemispherical emissivity of the film measured by the AE radiometer is 0.58, and the results are basically consistent.

Embodiment 2

[0050] The solar absorptivity of the film prepared in Example 1 increases significantly after being exposed to the atmosphere for a long time, and the Ag reflective layer of the film turns black. The analysis shows that the silver reflective layer has been oxidized because the polyimide substrate is not dense enough to allow the oxygen molecules in the atmosphere to penetrate into the Ag film to oxidize it. For this reason, the film of Example 1 is improved, and the improvement is in the Add a layer of 50nm thick Al between the polyimide substrate and the silver film 2 o 3 Barrier layer, improved film structure see Figure 4 . After the improved film was exposed to the atmosphere for 8 months, no decline in absorption rate was found.

Embodiment 3

[0052] A thermal control film with controllable emissivity, the substrate is polyimide, and the surface of the substrate is sequentially covered with 50nm thick Al 2 o 3 Barrier layer, 150nm thick silver film, 1.9μm thick Al 2 o 3 layer and a 550nm thick SiO 2 Floor. The spectral reflectance curve and 300K blackbody radiation intensity curve of the thermal control film are shown in Figure 5 (A is the 300K blackbody radiation intensity curve of the film of this embodiment, B is the spectral reflection curve of the film of this embodiment, and C is the spectral reflection curve of the film of Embodiment 1), it can be seen that SiO 2 The thickness of the layer can increase the absorption of 5 μm to 8 μm and improve the infrared emissivity. The solar absorptivity of the film is 0.12, the hemispheric emissivity is 0.68, and the absorbed radiation ratio is 0.18.

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Abstract

The invention discloses a thermal control film with controllable emissivity. The thermal control film comprises a substrate, a high-reflectivity layer with reflectivity of greater than or equal to 0.8, a high-emissivity layer with infrared emissivity of 0.3-0.7 and a protection layer, wherein the high-reflectivity layer, the high-emissivity layer and the protection layer are sequentially arranged on the substrate surface from inside to outside. The thermal control material disclosed by the invention can realize control of different absorption / emission ratios as well as lightweight design, and is applicable to a new-generation controllable-emissivity thermal control coating for spacecraft with the characteristics of light weight, small miniaturization and whole-spacecraft isothermality; and moreover, the thermal control film has the advantages of simple structure, low cost, convenience in preparation and high stability of space environment, meets different needs for emissivity at different parts of the spacecraft surface and satisfies the requirement for improving the space radiation resistance of the thermal control material.

Description

technical field [0001] The invention belongs to the field of aerospace materials, and in particular relates to a thermal control film with controllable emissivity. Background technique [0002] Since satellites and other spacecraft work in space in a vacuum environment, there is basically no heat transfer medium such as air around them, and the heat transfer method mainly depends on thermal radiation. An important means of thermal control. The existing thermal control film products are generally divided into two types: coating type (represented by various thermal control paints) and wrapped type (represented by polyimide film aluminum-coated secondary surface mirror), according to different use requirements Applied in different occasions. The common limitation is that the performance of each thermal control film is fixed, and its thermal control performance cannot be changed by adjusting the composition or thickness of each film layer. [0003] CN104561897A discloses a th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B9/00B32B9/04B32B15/18B32B15/20B32B27/28B32B27/30B32B27/36B32B15/00B32B17/00
CPCB32B9/00B32B9/04B32B9/041B32B9/045B32B15/00B32B15/18B32B15/20B32B17/00B32B27/281B32B27/30B32B27/36
Inventor 张伟文冯煜东杨淼张凯锋王志民王虎何延春周超李学磊王艺
Owner LANZHOU INST OF PHYSICS CHINESE ACADEMY OF SPACE TECH
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