High-emissivity glass type thermal control coating and preparation method thereof

Abstract

The invention relates to the technical field of surface engineering, and particularly provides a high-emissivity glass type thermal control coating and a preparation method thereof. The preparation method comprises the following steps: firstly, preparing a siloxane layer with the thickness of 1-3 microns on a first surface of a glass substrate by utilizing a plasma enhanced chemical vapor deposition technology, then preparing an indium tin oxide (ITO) layer with the thickness of 40-80 nm on the surface of the siloxane layer by utilizing a magnetron sputtering technology, and finally, preparing the indium tin oxide (ITO) layer with the thickness of 40-80 nm on the surface of the siloxane layer by utilizing the magnetron sputtering technology. A silver layer with the thickness of 150-400 nm and a nickel-chromium protective layer with the thickness of 100-400 nm are sequentially prepared on the second surface, opposite to the first surface, of the glass base material. The emissivity of the glass type thermal control coating prepared by the method is greater than 0.85, the solar absorptivity is less than 0.10, the glass type thermal control coating has the advantages of high heat dissipation efficiency, static resistance, good appearance and good space environment stability, the preparation method is simple, the process implementation is strong, and the efficient heat dissipation requirement of a high-power spacecraft can be met.

Description

Technical Field

[0001] The invention relates to the technical field of surface engineering, and in particular to a high-emissivity glass-type thermal control coating and a preparation method thereof. Background Art

[0002] Glass-type thermal control coating is a key material for thermal control of spacecraft. It has low solar absorption rate and high emissivity, and is mainly used in the radiation heat sink of spacecraft. The higher the emissivity, the stronger the heat dissipation capacity. The emissivity of the glass-type thermal control coating currently used is about 0.80, and the solar absorption rate is less than 0.1. With the improvement of spacecraft performance, the power required by the payload is also getting higher and higher, so a thermal control coating with higher heat dissipation capacity is needed. The emissivity of thermal control white paint can reach above 0.9, but its solar absorption rate is also relatively high, about 0.2. It will absorb more solar radiation in a sunlight environment, and the solar absorption rate will be even higher under the influence of the space environment.

[0003] Therefore, it is an urgent problem to develop a thermal control coating with high emissivity and low solar absorption rate, which can maintain high radiation heat dissipation capacity in both sunlight and shadow environments, and has good stability under the influence of space environments such as humidity, thermal cycle, ultraviolet radiation, and particle radiation. Summary of the invention

[0004] In view of the defects in the prior art, an object of the present invention is to provide a high-emissivity glass-type thermal control coating and a preparation method thereof.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a high-emissivity glass-type thermal control coating, comprising a substrate, a siloxane layer, an indium tin oxide layer, a silver layer and a nickel-chromium layer, wherein:

[0007] The substrate comprises a first surface and a second surface arranged opposite to each other;

[0008] The siloxane layer and the indium tin oxide layer are sequentially arranged on the first surface, the siloxane layer is relatively close to the substrate, and the indium tin oxide layer is relatively far away from the substrate;

[0009] The silver layer and the nickel-chromium layer are sequentially arranged on the second surface, the silver layer is relatively close to the substrate, and the nickel-chromium layer is relatively far away from the substrate.

[0010] Furthermore, the material of the substrate is glass, preferably high-transparency glass, more preferably quartz glass or cerium-doped glass.

[0011] Furthermore, the thickness of the siloxane layer is 1 to 3 μm.

[0012] Furthermore, the thickness of the indium tin oxide layer is 40-80 nm.

[0013] Furthermore, the thickness of the silver layer is 150-400 nm.

[0014] Furthermore, the thickness of the nickel-chromium layer is 100-400 nm.

[0015] Furthermore, the siloxane layer is prepared by plasma enhanced chemical vapor deposition (PECVD).

[0016] Furthermore, the indium tin oxide layer, the silver layer and the nickel chromium layer are all prepared by magnetron sputtering deposition.

[0017] In a second aspect, the present invention provides a method for preparing a high-emissivity glass-type thermal control coating, comprising the following steps:

[0018] Step (1) providing a substrate, which is pre-treated and ready for use;

[0019] Step (2) placing the substrate in a reaction chamber of a plasma enhanced chemical vapor deposition (PECVD) device, and evacuating the PECVD reaction chamber to a vacuum of 2×10 -3 Below Pa;

[0020] Step (3) introducing a mixed gas of a silicon source and oxygen into a reaction chamber of the PECVD device to perform PECVD deposition to form a siloxane layer on the first surface of the substrate;

[0021] Step (4) The substrate is transferred to a reaction chamber of a magnetron sputtering device, and the magnetron sputtering reaction chamber is evacuated to 2×10 -3 Below Pa;

[0022] Step (5) introducing a mixed gas of argon and oxygen into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form an indium tin oxide layer on the surface of the siloxane layer;

[0023] Step (6) Turning the substrate over and placing it in the magnetron sputtering reaction chamber to expose the second surface opposite to the first surface, and evacuating the vacuum to 2×10 -3 Below Pa;

[0024] Step (7) introducing argon gas into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form a silver layer on the second surface;

[0025] Step (8) introduces argon gas into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition, thereby forming a nickel-chromium layer on the surface of the silver layer to obtain a high-emissivity glass-type thermal control coating.

[0026] Furthermore, in the step (3), the conditions of PECVD are: using hexamethyldisiloxane or tetramethyldisiloxane as the silicon source, the silicon source flow rate is 5 to 50 sccm, the oxygen flow rate is 10 to 100 sccm, the deposition pressure is 5 to 30 Pa, the deposition power is 300 to 800 W, and the deposition is stopped when the thickness of the siloxane layer reaches 1 to 3 μm.

[0027] Furthermore, in the step (5), the conditions for magnetron sputtering deposition are: using an indium tin oxide ceramic target, an argon flow rate of 50 to 600 sccm, an oxygen flow rate of 5 to 100 sccm, a deposition pressure of 0.2 to 0.8 Pa, and a deposition power of 200 to 1000 W. When the thickness of the indium tin oxide layer reaches 40 to 80 nm, the deposition is stopped.

[0028] Furthermore, in step (7), the conditions for magnetron sputtering deposition are: using a silver target, an argon gas flow rate of 50 to 600 sccm, a deposition pressure of 0.2 to 1 Pa, a deposition power of 200 to 2000 W, and stopping the deposition when the thickness of the silver layer reaches 150 to 400 nm.

[0029] Furthermore, in step (8), the conditions for magnetron sputtering deposition are: using a nickel-chromium alloy target, an argon gas flow rate of 50 to 600 sccm, a deposition gas pressure of 0.2 to 0.6 Pa, a deposition power of 300 to 1500 W, and stopping deposition when the thickness of the nickel-chromium layer reaches 100 to 400 nm.

[0030] The technical solution of the present invention has the following advantages:

[0031] The emissivity of the glass-type thermal control coating provided by the present invention is increased to above 0.85, and the solar absorptivity is less than 0.1, and a high radiation heat dissipation capacity can be maintained in both sunlight and shaded environments. At the same time, it has an anti-static function and has good stability under environmental effects such as damp heat, thermal cycles, ultraviolet radiation, and particle radiation. The preparation method of the present invention has a simple process and strong process feasibility. The prepared glass-type thermal control coating has the advantages of high heat dissipation efficiency, anti-static, good appearance, and good stability in space environment, and can meet the efficient heat dissipation requirements of high-power spacecraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1It is a schematic diagram of the structure of a high-emissivity glass-type thermal control coating provided in an embodiment of the present invention.

[0034] Figure 2 It is a schematic diagram of the process flow of a method for preparing a high-emissivity glass-type thermal control coating provided in an embodiment of the present invention.

[0035] Figure 3 This is a graph showing the emissivity variation trend of glass-type thermal control coatings with different siloxane thicknesses provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0037] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the art can be used. The raw materials or instruments used are all conventional products that can be obtained commercially, including but not limited to the raw materials or instruments used in the examples of this application.

[0038] The following will be combined with the attached Figure 1 and attached Figure 2 , a high-emissivity glass-type thermal control coating and a preparation method thereof provided in an embodiment of the present invention are introduced in detail.

[0039] The technical problem to be solved by the present invention is to overcome the low heat dissipation efficiency of the thermal control coating in the prior art, which cannot meet the high-efficiency heat dissipation requirements of high-power spacecraft. To this end, a high-emissivity glass-type thermal control coating and its preparation method are proposed. The basic principle is: using plasma enhanced chemical vapor deposition (PECVD) technology, a siloxane layer with a thickness of 1 to 3 μm and an indium tin oxide (ITO) layer with a thickness of 40 to 80 nm are sequentially deposited on the first surface of the substrate, and a silver layer with a thickness of 150 to 400 nm and a nickel-chromium protective layer with a thickness of 100 to 400 nm are sequentially deposited on the second surface of the glass substrate opposite to the first surface by magnetron sputtering technology, which can effectively inhibit the influence of environmental thermal radiation on thermal control, increase the emissivity to above 0.85, and reduce the solar absorptivity to below 0.1. The prepared glass-type thermal control coating not only has high heat dissipation efficiency, but also has anti-static function. Under the influence of wet heat, thermal cycle, ultraviolet radiation, particle radiation and other environmental conditions, it shows good stability in space environment resistance and can be widely used in the high-efficiency heat dissipation requirements of high-power spacecraft.

[0040] Reference Figure 1The embodiment of the present invention provides a high emissivity glass-type thermal control coating, the structure of which is as follows Figure 1 As shown, it includes: a substrate, a siloxane layer, an indium tin oxide layer, a silver layer and a nickel chromium layer, wherein the substrate includes a first surface and a second surface arranged opposite to each other; the siloxane layer and the indium tin oxide layer are arranged in sequence on the first surface of the substrate, the siloxane layer is relatively close to the substrate, and the indium tin oxide layer is relatively far away from the substrate; the silver layer and the nickel chromium layer are arranged in sequence on the second surface of the substrate, the silver layer is relatively close to the substrate, and the nickel chromium layer is relatively far away from the substrate.

[0041] Furthermore, the material of the substrate is glass, preferably high-transparency glass, more preferably quartz glass or cerium-doped glass; the thickness of the siloxane layer is 1 to 3 μm, and it is prepared by plasma enhanced chemical vapor deposition (PECVD); the thickness of the indium tin oxide layer is 40 to 80 nm, the thickness of the silver layer is 150 to 400 nm, and the thickness of the nickel chromium layer is 100 to 400 nm, all of which are prepared by magnetron sputtering deposition.

[0042] Specifically, in a preferred embodiment of the present invention, the material of the substrate is cerium-doped glass, the thickness of the siloxane layer is 2 μm, the thickness of the indium tin oxide layer is 60 nm, the thickness of the silver layer is 300 nm, and the thickness of the nickel chromium layer is 200 nm.

[0043] Reference Figure 2 The present invention provides a method for preparing a high-emissivity glass-type thermal control coating, and the process flow is as follows: Figure 2 As shown, the following steps are included:

[0044] Step (1) providing a substrate, which is pre-treated and ready for use;

[0045] Step (2) placing the substrate in a reaction chamber of a plasma enhanced chemical vapor deposition (PECVD) device, and evacuating the PECVD reaction chamber to a vacuum of 2×10 -3 Below Pa;

[0046] Step (3) introducing a mixed gas of a silicon source and oxygen into a reaction chamber of a PECVD device to perform PECVD deposition to form a siloxane layer on the first surface of the substrate;

[0047] Step (4) The substrate is transferred to the reaction chamber of the magnetron sputtering equipment, and the magnetron sputtering reaction chamber is evacuated to 2×10 -3 Below Pa;

[0048] Step (5) introducing a mixed gas of argon and oxygen into a magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form an indium tin oxide layer on the surface of the siloxane layer;

[0049] Step (6) Turn the substrate over and place it in a magnetron sputtering reaction chamber to expose a second surface opposite to the first surface, and evacuate the surface to 2×10 -3 Below Pa;

[0050] Step (7) introducing argon gas into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form a silver layer on the second surface of the substrate;

[0051] Step (8) introduces argon gas into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form a nickel-chromium layer on the surface of the silver layer to obtain a high-emissivity glass-type thermal control coating.

[0052] Furthermore, in step (3), the conditions of PECVD are: using hexamethyldisiloxane or tetramethyldisiloxane as the silicon source, the silicon source flow rate is 5 to 50 sccm, the oxygen flow rate is 10 to 100 sccm, the deposition pressure is 5 to 30 Pa, the deposition power is 300 to 800 W, and the deposition is stopped when the thickness of the siloxane layer reaches 1 to 3 μm.

[0053] Furthermore, in step (5), the conditions for magnetron sputtering deposition are: using an indium tin oxide ceramic target, an argon flow rate of 50 to 600 sccm, an oxygen flow rate of 5 to 100 sccm, a deposition pressure of 0.2 to 0.8 Pa, and a deposition power of 200 to 1000 W. When the thickness of the indium tin oxide layer reaches 40 to 80 nm, the deposition is stopped.

[0054] Furthermore, in step (7), the conditions for magnetron sputtering deposition are: using a silver target, an argon gas flow rate of 50 to 600 sccm, a deposition pressure of 0.2 to 1 Pa, a deposition power of 200 to 2000 W, and stopping the deposition when the thickness of the silver layer reaches 150 to 400 nm.

[0055] Furthermore, in step (8), the conditions for magnetron sputtering deposition are: using a nickel-chromium alloy target, an argon gas flow rate of 50 to 600 sccm, a deposition pressure of 0.2 to 0.6 Pa, a deposition power of 300 to 1500 W, and stopping the deposition when the thickness of the nickel-chromium layer reaches 100 to 400 nm.

[0056] Specifically, in a preferred embodiment of the present invention, the method for preparing the high-emissivity glass-type thermal control coating comprises the following steps:

[0057] Step (1) providing a cerium-doped glass substrate, which is pre-treated and ready for use;

[0058] Step (2) placing the substrate in a reaction chamber of a plasma enhanced chemical vapor deposition (PECVD) device, and evacuating the PECVD reaction chamber to a vacuum of 1.5×10 -3 Pa;

[0059] Step (3) introducing a mixed gas of hexamethyldisiloxane and oxygen into a reaction chamber of a PECVD device to perform PECVD deposition to form a siloxane layer on the first surface of the substrate, wherein the conditions for PECVD deposition are: a hexamethyldisiloxane flow rate of 40 sccm, an oxygen flow rate of 20 sccm, a deposition pressure of 20 Pa, a deposition power of 800 W, a deposition time of 50 min, and stopping the deposition when the thickness of the siloxane layer reaches 2 μm;

[0060] Step (4) The substrate is transferred to the reaction chamber of the magnetron sputtering equipment, and the magnetron sputtering reaction chamber is evacuated to 1.5×10 -3 Pa;

[0061] Step (5) introducing a mixed gas of argon and oxygen into a magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form an indium tin oxide layer on the surface of the siloxane layer, wherein the conditions of the magnetron sputtering deposition are: an argon gas flow rate of 200 sccm, an oxygen flow rate of 20 sccm, a deposition pressure of 0.4 Pa, a deposition power of 700 W, and a deposition time of 10 min. When the thickness of the indium tin oxide layer reaches 60 nm, the deposition is stopped;

[0062] Step (6) The substrate is turned over and placed in a magnetron sputtering reaction chamber to expose a second surface opposite to the first surface, and the vacuum is evacuated to 1.5×10 -3 Pa;

[0063] Step (7) introducing argon gas into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form a silver layer on the second surface of the substrate, wherein the conditions of the magnetron sputtering deposition are: argon gas flow rate of 200 sccm, deposition pressure of 0.6 Pa, deposition power of 800 W, deposition time of 20 min, and stopping the deposition when the thickness of the silver layer reaches 300 nm;

[0064] Step (8) introducing argon gas into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form a nickel-chromium layer on the surface of the silver layer to obtain a high-emissivity glass-type thermal control coating, wherein the conditions of the magnetron sputtering deposition are: argon gas flow rate of 200 sccm, deposition pressure of 0.4 Pa, deposition power of 600 W, deposition time of 20 min, and stopping the deposition when the thickness of the nickel-chromium reaches 200 nm.

[0065] See also Figure 3 The present invention conducts emissivity tests on glass-type thermal control coatings with different siloxane thicknesses prepared in the examples. Figure 3As shown, the emissivity varies with the thickness of the siloxane. When the thickness of the siloxane layer increases to more than 1 μm, the emissivity will increase to more than 0.85. However, when the thickness of the siloxane is too large, the emissivity decreases. The reason is that the increase in the thickness of the siloxane will increase the stress of the entire thermal control coating. It can be seen that the thickness of the siloxane layer should be 1 to 3 μm.

[0066] In summary, the embodiment of the present invention adopts plasma enhanced chemical vapor deposition, first deposits a siloxane layer with a thickness of 1 to 3 μm on the first surface of the glass substrate, then uses magnetron sputtering technology to deposit an indium tin oxide layer with a thickness of 40 to 80 nm on the surface of the siloxane layer, and then uses magnetron sputtering technology to deposit a silver layer with a thickness of 150 to 400 nm and a nickel-chromium protective layer with a thickness of 100 to 400 nm on the second surface of the glass substrate opposite to the first surface, which can effectively suppress the influence of environmental thermal radiation on thermal control, increase the emissivity to above 0.85, and reduce the solar absorptivity to below 0.1, and maintain a high radiation heat dissipation capacity in both sunlight and shadow environments. In addition, since the increase in the thickness of siloxane will increase the stress of the entire thermal control coating, the thickness of the siloxane layer is preferably 1 to 3 μm. In addition, the high-emissivity glass-type thermal control coating provided by the embodiment of the present invention not only has high heat dissipation efficiency, but also has anti-static function. It exhibits good stability in space environment under the influence of humidity, heat, thermal cycle, ultraviolet radiation, particle radiation and other environments. The preparation method is simple and the process is easy to implement. It can be widely used in the efficient heat dissipation needs of high-power spacecraft.

[0067] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A high emissivity glass-type thermal control coating, characterized in that: The invention comprises a substrate, a siloxane layer, an indium tin oxide layer, a silver layer and a nickel chromium layer, wherein: The substrate comprises a first surface and a second surface arranged opposite to each other; The siloxane layer and the indium tin oxide layer are sequentially disposed on the first surface, the siloxane layer is relatively close to the substrate, and the indium tin oxide layer is relatively far away from the substrate; The silver layer and the nickel-chromium layer are sequentially arranged on the second surface of the substrate, the silver layer is relatively close to the substrate, and the nickel-chromium layer is relatively far away from the substrate.

2. The high emissivity glass type thermal control coating according to claim 1, characterized in that: The substrate is a glass substrate.

3. The high emissivity glass-type thermal control coating according to claim 1, characterized in that: The thickness of the siloxane layer is 1-3 μm, the thickness of the indium tin oxide layer is 40-80 nm, the thickness of the silver layer is 150-400 nm, and the thickness of the nickel chromium layer is 100-400 nm.

4. The high emissivity glass type thermal control coating according to claim 1, characterized in that: The siloxane layer is prepared by plasma enhanced chemical vapor deposition (PECVD); the indium tin oxide layer, the silver layer and the nickel chromium layer are all prepared by magnetron sputtering deposition.

5. A method for preparing the high-emissivity glass-type thermal control coating according to any one of claims 1 to 4, comprising the following steps: Step (1) providing a substrate, which is pre-treated and ready for use; Step (2) placing the substrate in a reaction chamber of a plasma enhanced chemical vapor deposition (PECVD) device, and evacuating the PECVD reaction chamber to a vacuum of 2×10 -3 Below Pa; Step (3) introducing a mixed gas of a silicon source and oxygen into a reaction chamber of the PECVD device to perform PECVD deposition to form a siloxane layer on the first surface of the substrate; Step (4) The substrate is transferred to a reaction chamber of a magnetron sputtering device, and the magnetron sputtering reaction chamber is evacuated to 2×10 -3 Below Pa; Step (5) introducing a mixed gas of argon and oxygen into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form an indium tin oxide layer on the surface of the siloxane layer; Step (6) Turning the substrate over and placing it in the magnetron sputtering reaction chamber to expose the second surface opposite to the first surface, and evacuating the vacuum to 2×10 -3 Below Pa; Step (7) introducing argon gas into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition to form a silver layer on the second surface; Step (8) introduces argon gas into the magnetron sputtering reaction chamber to perform magnetron sputtering deposition, thereby forming a nickel-chromium coating on the surface of the silver layer to obtain a high-emissivity glass-type thermal control coating.

6. The method for preparing a high-emissivity glass-type thermal control coating according to claim 5, characterized in that: In the step (3), the conditions of PECVD are: using hexamethyldisiloxane or tetramethyldisiloxane as the silicon source, the silicon source flow rate is 5 to 50 sccm, the oxygen flow rate is 10 to 100 sccm, the deposition pressure is 5 to 30 Pa, the deposition power is 300 to 800 W, and the deposition is stopped when the thickness of the siloxane layer reaches 1 to 3 μm.

7. The method for preparing a high-emissivity glass-type thermal control coating according to claim 5, characterized in that: In the step (5), the conditions for magnetron sputtering deposition are: using an indium tin oxide ceramic target, an argon flow rate of 50 to 600 sccm, an oxygen flow rate of 5 to 100 sccm, a deposition pressure of 0.2 to 0.8 Pa, and a deposition power of 200 to 1000 W. When the thickness of the indium tin oxide layer reaches 40 to 80 nm, the deposition is stopped.

8. The method for preparing a high-emissivity glass-type thermal control coating according to claim 5, characterized in that: In the step (7), the conditions for magnetron sputtering deposition are: using a silver target, an argon gas flow rate of 50 to 600 sccm, a deposition pressure of 0.2 to 1 Pa, a deposition power of 200 to 2000 W, and stopping the deposition when the thickness of the silver layer reaches 150 to 400 nm.

9. The method for preparing a high-emissivity glass-type thermal control coating according to claim 5, characterized in that: In the step (8), the conditions for magnetron sputtering deposition are: using a nickel-chromium alloy target, an argon gas flow rate of 50 to 600 sccm, a deposition pressure of 0.2 to 0.6 Pa, a deposition power of 300 to 1500 W, and stopping the deposition when the thickness of the nickel-chromium layer reaches 100 to 400 nm.

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