CN114381709A - Coating, use and preparation method - Google Patents

Abstract

The invention provides a coating, application and a preparation method thereof. The special catalyst intermediate layer is prepared, and the carbon nano structure prepared by plasma enhanced chemical vapor deposition is introduced into the black body coating, so that the coating has high light absorption performance and high emissivity, has good bonding force with a substrate material, and improves stability and durability.

Description

Coating, use and preparation method

technical field

The invention relates to coatings, uses and preparation methods, and belongs to the technical field of preparation of black body coatings.

Background technique

The black body is an idealized physical model based on Planck's law. It is an ideal diffuse reflector and has a wide range of applications in scientific research, aerospace, and industrial production. As a broadband infrared radiation source, the wavelength range of the highly stable medium-temperature surface source blackbody covers the band from near-infrared to far-infrared, and is the basis for radiation theoretical analysis and radiation measurement. Measurement, infrared detector calibration and infrared target simulation testing and overall performance evaluation are more and more widely used. As an infrared target source, the surface blackbody can be applied to the detection, identification and positioning of the infrared system; it can be used as the background of the radiation source to detect the interference of the infrared system; it can also be used as the calibration radiation source for the radiation calibration of the blackbody. These applications have high requirements on the temperature stability and radiation accuracy of the radiation surface.

The blackbody coating is one of the core components of the area source blackbody, and its parameters directly determine the performance of the area source blackbody. At present, the coating used for common black bodies is a special paint with high emissivity, which can be deposited by brushing or spraying, such as polymer plus carbon or silicone resin plus metal oxide, etc., but its emissivity at room temperature or high temperature Lower, its components are generally polymers (such as silicone rubber, polyurethane, epoxy, silicone, etc.) and fillers (such as carbon, metal oxides, etc.), however, these high emissivity coatings are generally 0.92 emissivity ～0.95, still cannot meet the requirements of a new generation of high-performance radiation sources; in addition, due to the poor adhesion of some polymers to metal substrates, and the polymers are easy to age and crack, these blackbody coatings still have low stability and poor durability. The problem.

Carbon nanostructures prepared by plasma-enhanced chemical vapor deposition have very high light absorption and infrared emissivity. However, existing carbon nanocoatings based on plasma-enhanced chemical vapor deposition have high substrate selectivity, only It can be fabricated on specific substrates such as metal or silicon wafers, and the in-plane uniformity will decrease as the size of the substrate increases. At the same time, due to the weak bonding force between carbon materials and substrate materials, the mechanical strength of the coating is low, and the stability and durability are poor, so it is rarely used in the preparation of surface source blackbody radiation layers.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a coating with high light absorption performance, high emissivity, high stability and good durability, application and preparation method thereof.

Technical solution of the present invention: the coating includes a catalyst intermediate layer and a carbon-based coating, the catalyst intermediate layer is an island-shaped structure, and the carbon-based coating is deposited on the catalyst with the island-shaped structure by a plasma-enhanced chemical vapor deposition process. on the middle layer.

A black body, comprising a black body base and a black body coating attached to the black body base, the black body coating comprising a catalyst intermediate layer and a carbon-based coating, the catalyst intermediate layer is an island structure, and the carbon-based coating passes through Plasma-enhanced chemical vapor deposition process deposits on the catalyst intermediate layer of island structure.

A coating preparation method is realized by the following steps:

substrate pretreatment;

Preparation of catalyst intermediate layer,

The island structure formed by preparing the transition metal catalyst on the substrate;

Carbon based coating deposition,

The carbon-based coating is obtained by depositing on the catalyst intermediate layer of island structure.

An application of a composite coating consisting of a catalyst intermediate layer and a carbon-based coating on the catalyst intermediate layer in a black body coating.

The beneficial effects of the present invention compared with the prior art:

(1) The present invention prepares a special catalyst intermediate layer, and introduces the carbon nanostructure prepared by plasma enhanced chemical vapor deposition into the black body coating, so that the coating has high light absorption performance, high emissivity, and good bonding force with the base material , improve stability and durability;

(2) In the present invention, by preparing an island-shaped catalyst intermediate layer, the subsequently deposited carbon-based coating has a loose nano-sheet structure with high roughness, improves the emissivity of the coating, and satisfies the new generation of high-performance radiation source requirements;

(3) The present invention can prepare carbon-based coatings with high surface roughness, and the emissivity at room temperature and 200°C is not less than 0.98;

(4) The present invention adopts relatively mature technologies such as plasma enhanced chemical vapor deposition, which can be used for the preparation of large-area coatings (maximum 1m×1m), and the prepared blackbody coating has the advantages of high uniformity and good stability;

(5) The present invention adopts a catalyst intermediate layer, so that the plasma enhanced chemical vapor deposition can be applied to substrates with high thermal conductivity such as metals and graphite, so as to realize the applicability on various substrates, and can be used for the preparation of a new generation of high-performance radiation sources;

(6) In the present invention, due to the higher emissivity and thermal conductivity of the carbon-based coating, the blackbody of the blackbody coating prepared by the present invention has higher comprehensive properties, which is a necessary condition for preparing a high-performance radiation source.

Description of drawings

Fig. 1 is the preparation flow chart of the present invention;

2 is a scanning electron microscope photograph of a carbon-based blackbody coating deposited on a copper substrate in Example 1 of the present invention;

FIG. 3 is a scanning electron microscope photograph of a carbon-based blackbody coating deposited on an aluminum substrate in Example 2 of the present invention.

Detailed ways

The present invention will be described in detail below with reference to specific examples and accompanying drawings.

The invention provides a coating, comprising a catalyst intermediate layer and a carbon-based coating on the catalyst intermediate layer, the catalyst intermediate layer is an island-shaped structure, and the carbon-based coating is deposited on the catalyst with the island-shaped structure by a plasma enhanced chemical vapor deposition process on the middle layer.

The catalyst intermediate layer of the present invention is a transition metal coating, which is deposited on the substrate by methods such as electroplating, magnetron sputtering or electron beam deposition.

The catalyst of the present invention adopts a transition metal catalyst with strong interaction with carbon materials, including but not limited to nickel, cobalt, iron, manganese and other materials, and the catalyst is preferably metal nickel. The deposition of the catalyst has a very important influence on the deposition of the blackbody coating. The type, thickness and morphology of the catalyst play a decisive role in the microstructure and thermal radiation performance of the blackbody coating. In the present invention, the thickness of the catalyst intermediate layer is preferably 5 nanometers to 20 nanometers, preferably not more than 10 nanometers, and the carbon-based coating deposited on the catalyst intermediate layer can form a loose nano-sheet structure. If the thickness of the catalyst intermediate layer is too thick, the deposited carbon nanostructures are very dense and have low emissivity; while the thickness of the catalyst intermediate layer is too small, a continuous carbon-based coating cannot be obtained.

The deposition amount of the catalyst layer in the present invention is 0.01-1 mg/cm ² , and by controlling the deposition amount of the catalyst layer, the growth of the catalyst layer is controlled in the nucleation stage, and an island-like structure can be formed. The existence of the island-like structure can make the carbon material form a loose nano-sheet structure during the growth process, and the rough structure can increase the emissivity of the coating. If the catalyst deposition amount is too high, coalescence will occur between catalyst particles, the growth of carbon materials on the substrate will not be selective, and the resulting carbon nanostructures will be relatively denser and have lower emissivity.

The present invention prepares a catalyst intermediate layer, and in the presence of these catalysts, carbon precursors such as common methane, ethylene, acetylene, etc. are decomposed into carbon under the action of the catalyst, and grow along a specific crystal plane of the carbon to form a sheet-like structure , and finally a nanosheet layered carbon-based coating with higher roughness was obtained.

The carbon-based coating of the present invention utilizes a plasma-enhanced chemical vapor deposition method to perform vapor deposition of carbon materials on a catalyst intermediate layer-supported substrate.

In the plasma enhanced chemical vapor deposition process of the present invention, the flow rate of the reactive gas is 0.1-5L/h, preferably 0.1-2L/h; under the process control of the flow rate of the reactive gas being 0.1-5L/h, the deposited carbon-based coating has The carbon nanosheet structure, and the thickness of the sheet is between 10 and 50 nm, and the carbon-based coating is easy to form high roughness. When the thickness of the lamella is in the nanometer size range between 10 and 50 nm, due to the quantum size effect, the electrons excited by light will be more damped, so the light absorption effect is stronger. According to Kirchhoff's law, the emissivity is higher. high.

If the flow rate is too high and exceeds 5L/h, the obtained carbon-based coating has a very dense structure and low emissivity, which is not practical. When the flow rate is less than 0.1L/h, the deposition rate is very slow and the production efficiency is too low.

In the present invention, the thickness of the carbon-based coating is preferably 500 nm to 20 μm. If the thickness of the coating is too low, it will not be able to fully absorb the incident light, and the reflection of the substrate will lead to an increase in reflectivity and a decrease in emissivity. If it is high, the supporting force of the carbon nanostructure is weak, and the stability of the coating is reduced.

Other plasma-enhanced chemical vapor deposition processes in the present invention are known in the art, and those skilled in the art can adjust the flow rate of the reactive gas and the thickness of the carbon-based coating in combination with actual needs.

The present invention prefers the following plasma enhanced chemical vapor deposition conditions:

a. Carrier gas: choose hydrogen or argon, and 1% to 20% of nitrogen can be added to the carrier gas as a nitrogen doping source;

b. Reactive gas: carbon precursor (methane, ethylene, acetylene, etc.)

c. Gas purity: the purity of carrier gas and reaction gas can be adjusted between 3N and 5N;

d. Flow rate of reaction gas: 0.1～5L/h;

e. Carrier gas flow rate: 5～10L/h;

f. The total pressure of the reaction chamber: 1×10 ^-5 Torr～500×10 ^-5 Torr;

g. Substrate temperature: 400～800℃;

h. Plasma power: 10W～100W;

i. Deposition time: 10min～50min;

Preferably, in plasma-enhanced chemical vapor deposition, the vacuum is firstly pumped to the order of magnitude of 10-50 Torr, washed with argon or hydrogen, and the substrate is heated to a specified temperature, and then the reaction gas/carrier gas is introduced, and the plasma device is turned on. chemical vapor deposition.

Further, the application of the composite coating composed of the catalyst intermediate layer and the carbon-based coating on the catalyst intermediate layer of the present invention in the black body coating.

Further, as shown in FIG. 1 , the present invention provides a coating preparation method, which includes substrate pretreatment, catalyst intermediate layer deposition and carbon-based coating deposition.

Substrate pretreatment:

The pretreatment of the substrate refers to the removal of the substrate by chemical (including but not limited to acid washing, alkali washing, water or organic solvent washing), physical (including but not limited to sandblasting, grinding, ultrasonic) or a combination of the two methods. Impurities on the surface of the substrate material that improve the bond between the substrate and the subsequently deposited coating.

The selection of the pretreatment mode of the substrate is a well-known technology in the art, and is specifically determined by those skilled in the art according to the actual situation.

It is preferable to use an organic solvent for cleaning after sandblasting or sanding. This combined treatment method is conducive to the formation of a rough surface and can increase the emissivity of the final resulting coating.

Preparation of catalyst intermediate layer:

The catalyst intermediate layer adopts a transition metal catalyst, the thickness of the catalyst intermediate layer is 5 nanometers to 20 nanometers, and the morphology of the catalyst intermediate layer of the present invention is an island structure.

In this step, a known method such as electroplating, magnetron sputtering or electron beam deposition is used to form a catalyst intermediate layer on the substrate. According to the above requirements for obtaining a catalyst intermediate layer, those skilled in the art adjust the prior art to obtain a suitable catalyst. process parameters.

Carbon based coating deposition:

In this step, the carbon-based coating is deposited on the catalyst intermediate layer by plasma-enhanced chemical vapor deposition. The flow rate of the reaction gas is 0.1-5 L/h, and the thickness of the carbon-based coating is preferably 500 nm to 20 μm.

Further, the present invention provides a blackbody comprising a blackbody base and a blackbody coating.

Substrates include metal substrates (including but not limited to brass, copper, aluminum, stainless steel) or extruded graphite substrates. Preferably, the substrate has high thermal conductivity (thermal conductivity is greater than 20W/(m·K)), which is convenient for heating and cooling control of the blackbody coating, and its strong uniform heat performance can ensure that the in-plane temperature has a relatively high temperature. uniformity.

Example 1

The copper with an area of 20cm×20cm and a purity of 99.8% was used as the substrate. After sandblasting, the surface was scrubbed, ultrasonicated and rinsed with acetone, and then a layer of 10 was deposited on the copper substrate by electron beam deposition. A nanometer-thick, deposited amount of 0.05 mg/ ^cm2 of metallic nickel with island-like structure was used as the catalyst intermediate layer.

The above-mentioned copper substrate was placed in a plasma-enhanced chemical vapor deposition apparatus, evacuated to 1 × 10 ^-5 Torr, rinsed with argon three times, the substrate was heated to 800° C., and a mixed gas of methane/argon/nitrogen was introduced ( The flow rates of the three are 0.5, 9.0 and 1.0 L/h, respectively). The output power of the plasma generator was adjusted to 50W, and the carbon-based coating was obtained after 30 min of deposition.

The morphology of the coating is shown in Figure 2, and its structure is a randomly arranged carbon nanosheet structure with a thickness of 20 nanometers and a height of 5 micrometers. Due to its very loose structure and high surface roughness, its emissivity is 0.991 at room temperature and 0.995 at 200 °C.

Embodiment 2, 3

Other conditions and preparation process are the same as in Example 1. When the thickness of the catalyst intermediate layer is 5 nm and 8 nm, and the deposition amount is 0.02-0.04 mg/cm ² , the morphology and emissivity of the coating are similar to those in Example 1.

Example 4

Other conditions and preparation process are the same as in Example 1. When the thickness of the catalyst intermediate layer is 20 nm and the deposition amount is 0.7 mg/cm ² , the distance between the obtained catalyst island-like structures is small. The carbon nanosheet structure in the carbon coating structure is denser than that of Examples 1-3, the sheet thickness is 50 nanometers, and the carbon coating thickness is 10 micrometers.

Example 5

An aluminum plate with an area of 50cm×50cm was used as the substrate. After sanding, the surface was scrubbed with acetone. After drying quickly, a 10-nanometer-thick layer was deposited on the aluminum substrate by chemical plating. The deposition amount was 0.05mg/ ^cm2 of metallic nickel with island-like structure was used as the catalyst intermediate layer.

The above aluminum substrate was placed in a plasma-enhanced chemical vapor deposition equipment, evacuated to 1 × 10 ^-5 Torr, rinsed three times with hydrogen, and the substrate was heated to 400° C. 1.0 and 10L/h). The output power of the plasma generator was adjusted to 100 W, and the carbon-based coating was obtained after 20 min of deposition.

The morphology of the coating is shown in Figure 3, and its structure is a randomly arranged carbon nanosheet structure, the thickness of the sheet is 50 nanometers, and the height is 3 micrometers. Due to its very loose structure and high surface roughness, its emissivity is 0.982 at room temperature and 0.987 at 200 °C.

Embodiment 6, 7

The mixed gas of methane/hydrogen was introduced, and the flow rates of the two were respectively (5.0 and 10L/h) and (0.1, 10L/h), and other conditions and processes were the same as those in Example 6, and the coating morphology and emissivity were obtained as in Example 6. 5 is similar.

The parts of the present invention that are not described in detail are well known to those skilled in the art.

Claims (12)

1. A coating, characterized by: the catalyst comprises a catalyst middle layer and a carbon-based coating, wherein the catalyst middle layer is of an island-shaped structure, and the carbon-based coating is deposited on the catalyst middle layer of the island-shaped structure through a plasma enhanced chemical vapor deposition process.

2. A coating according to claim 1, wherein: the catalyst intermediate layer is a transition metal catalyst and has a thickness of 5-20 nm.

3. A coating according to claim 1, wherein: the deposition amount of the catalyst intermediate layer is 0.01-1 mg/cm²。

4. A coating according to claim 2, wherein: the thickness of the catalyst intermediate layer is not more than 10 nanometers.

5. A coating according to claim 1, wherein: the carbon-based coating has a carbon nano-sheet layer structure, and the thickness of the sheet layer is 10-50 nm.

6. A blackbody comprising a blackbody substrate and a blackbody coating attached to the blackbody substrate, wherein the blackbody coating is any one of the coatings of claims 1-5.

7. A coating preparation method is characterized by comprising the following steps:

pre-treating a substrate;

preparing a catalyst intermediate layer, namely preparing a catalyst intermediate layer,

preparing an island-shaped structure formed by a transition metal catalyst on a substrate;

the preparation of the carbon-based coating,

and depositing the carbon-based coating on the catalyst intermediate layer with the island-shaped structure.

8. A method of preparing a coating according to claim 7, wherein: in the preparation step of the catalyst intermediate layer, the thickness of the catalyst intermediate layer is 5 to 20 nanometers, and the deposition amount is 0.01 to 1mg/cm²。

9. A method of preparing a coating according to claim 8, wherein: in the preparation step of the catalyst intermediate layer, the thickness of the catalyst intermediate layer is not more than 10 nanometers.

10. A method of preparing a coating according to claim 7, wherein: in the carbon-based coating deposition step, the carbon-based coating has a carbon nano sheet layer structure, and the thickness of the sheet layer is 10-50 nm.

11. A method of preparing a coating according to claim 10, wherein: in the carbon-based coating deposition step, a plasma enhanced chemical vapor deposition process is adopted, and the flow speed of reaction gas is 0.1-5L/h.

12. Use of a coating according to any one of claims 1 to 5 in a blackbody coating.

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