CN114163853A

CN114163853A - High-radiation slurry and preparation method and application thereof

Info

Publication number: CN114163853A
Application number: CN202011590384.9A
Authority: CN
Inventors: 凤晓华; 黄晶; 吴双杰; 周平; 刘奕; 李华
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS; Cixi Institute of Biomedical Engineering CNITECH of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS; Cixi Institute of Biomedical Engineering CNITECH of CAS
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2022-03-11
Anticipated expiration: 2040-12-29
Also published as: CN114163853B

Abstract

The invention relates to the technical field of heat dissipation coatings, and discloses high-radiation slurry and a preparation method and application thereof. The slurry comprises 15-40 wt.% of polyurethane, 5-10 wt.% of titanium oxide, 10-40 wt.% of acrylic acid, 1-3 wt.% of foaming agent, 1-5 wt.% of nano carbon powder, 5-20 wt.% of metal oxide and 1-5 wt.% of curing agent. The paint can be deposited on the surfaces of different shapes and different substrates by spraying or brushing. According to the invention, the high absorption characteristic of polyurethane in a near-middle infrared region, nano carbon powder subjected to nitriding surface modification treatment and metal oxides with different absorption light bands are utilized, so that the thermal radiance and the heat dissipation performance of the coating are comprehensively improved. Under the wave band of 2.5-20 μm, the heat radiation rate of the coating can reach more than 0.95, and the temperature difference can reach more than 10 ℃ in a 30min calorimetry test. Has wide application prospect in the insufficient positions of heat conduction, convection and the like.

Description

High-radiation slurry and preparation method and application thereof

Technical Field

The invention relates to the technical field of heat dissipation coatings, and particularly relates to high-radiation slurry and a preparation method and application thereof.

Background

The heat dissipation mode mainly includes radiation heat dissipation, conduction heat dissipation, convection heat dissipation and evaporation heat dissipation. In space, because no medium exists, heat can be dissipated only in the form of heat radiation. The satellite or space station must control the heat by radiating heat from the radiator. Radiation heat dissipation refers to a heat dissipation form in which a body radiates heat to an external cooler object. The radiation heat dissipation depends mainly on the difference between the substrate temperature and the ambient cooler ambient temperature. The greater the difference between the substrate temperature and the ambient environment, the greater the amount of radiated heat. The higher the emissivity of the material, the better its radiative heat dissipation properties.

The radiation heat dissipation enhancement mainly comprises the steps of carrying out anodic oxidation treatment on the surface of a heat dissipation device and coating a radiation heat dissipation coating. The implementation method of the surface anodic oxidation treatment is relatively complex, the cost is high, and certain limitations are realized; the coating of the radiation heat dissipation coating is simple and convenient in construction, low in price, not limited by the material of the device, capable of playing a role in protecting the device and widely concerned. At present, the heat dissipation materials which are mature and applied in the market comprise a graphite sheet, a metal back plate, heat conduction silica gel and the like. Graphite sheets are easy to obtain and low in cost, but the surfaces of devices with curved surfaces are not applicable, and the radiance of the devices is only about 0.8; the metal back plate has the disadvantages of heavy weight and poor hand feeling; the heat conducting silica gel has poor heat conducting effect and is easy to generate pollution.

For example, CN 105949903 a discloses a high-efficiency heat-dissipating coating and an application method thereof, the heat-dissipating material comprises the following components by mass percent: 5 to 20 percent of superfine graphite; 1-10% of infrared radiation powder; 20 to 50 percent of binder; 30-50% of solvent; 0.1 to 3 percent of dispersant, the sum of the proportions of the components is 100 percent, and the preparation method comprises the following steps: mixing the weighed superfine graphite, the infrared radiation powder, the binder, the dispersant and the solvent, mixing the ingredients, and uniformly stirring to obtain slurry; the slurry is used on the surface of a metal radiating fin of the electronic equipment, so that the surface temperature of the electronic equipment can be effectively reduced, and the full-wave-band radiance is stabilized above 0.96 for a long time; the temperature of the metal radiating fin of the electronic equipment is reduced by 8-10 ℃ after the high-efficiency heat-radiating coating is coated compared with that of the surface before coating under the working state of 80-100 ℃. However, the addition amount of the ultrafine graphite is about 10%, and the cost is relatively high.

The development of novel high-radiation slurry and a coating preparation technology can meet the requirements of special environments, such as narrow space areas and insufficient places such as heat conduction and convection, and the heat radiation effect of the coating is utilized to reduce the temperature of the surface of an object. Besides, high-power LED lamps, flat display screens using LEDs as light sources, high-power heat dissipation fins, etc. are possible application fields.

The nano carbon material has an ultra-fine nano structure, an ultra-large specific surface area and a very high emissivity, and has a refractive index of less than 0.1% for light rays as a nano material with excellent comprehensive performance. The emissivity coefficient of the arrayed carbon nano tubes can even reach 0.99, which is close to 1; the nano carbon material has good conductivity, so that compared with other granular heat-dissipating fillers, a heat-conducting network is easy to form, the reinforcing and toughening effects on the coating are obvious, and a film which is uniform, smooth and excellent in mechanical property can be formed by coating a thin layer of 5-10 mu m; meanwhile, the better the degree of crystallization of the surface of the nano carbon material is, the better the heat dissipation effect of the coating is. At present, many researches and patents are provided for conductive heat dissipation and convective heat dissipation, and documents with high radiation rate as a requirement for heat dissipation in special environments are not reported.

CN 106590331A discloses a special heat radiation coating for a radiator and a preparation method thereof, wherein the coating is prepared from the following components in parts by weight: 35-45 parts of epoxy resin, 10-18 parts of nano silicon carbide, 10-18 parts of nano aluminum oxide, 1.5-2.5 parts of carbon nano tube, 25-35 parts of liquid aluminum dihydrogen phosphate, 1.5-2.5 parts of polyoxyethylene polyoxypropylene ether and 20-30 parts of water. However, the heat dissipation effect is still insufficient, and the specific heat radiation efficiency cannot be determined without testing the heat radiation coefficient.

Disclosure of Invention

Aiming at the problems of insufficient radiation rate and poor heat dissipation effect of heat dissipation materials in the prior art, the invention provides the high-radiation slurry added with the nano-carbon material, the polyurethane is used as a matrix, and the nano-titanium oxide and the nano-carbon are matched, so that the obtained slurry has the high radiation rate of more than 0.95, and can play a good heat dissipation effect in some special application environments.

In order to achieve the purpose, the invention adopts the technical scheme that:

the high-radiation slurry comprises the following raw material components in percentage by mass:

the metal oxide comprises any one or more of silicon oxide, aluminum oxide and iron oxide.

The invention aims to improve the thermal radiance of a coating in an infrared band, polyurethane with absorption effect on the infrared band is selected as a polymer matrix, the polyurethane has strong infrared absorption peaks in a band of 2.5-10 mu m, silicon oxide has strong infrared absorption peaks in a band of 25.3 mu m, 21.8 mu m, 14 mu m, 12 mu m, 9.5 mu m and 8.5 mu m, aluminum oxide has strong infrared absorption peaks in a band of 3 mu m, 9.3 mu m, 13.4 mu m and 16.2 mu m, iron oxide has strong absorption peaks in a band of 32.5 mu m, 21.6 mu m and 18.8 mu m, and titanium oxide has strong characteristic absorption peaks in a band of 21.8 mu m and 29 mu m. The nano carbon material has little or no absorption peak of infrared spectrum without too many functional groups. After surface modification, strong absorption peaks occur at about 3.0 μm, 7.1 μm and 10 μm. The invention adjusts the absorption peak intensity of the carbon material in a special wave band through the surface modification of the carbon material and improves the absorption of the coating in a wave band of 2.5-25 mu m integrally under the synergistic action of the carbon material and the infrared absorption peak of other metal oxides, thereby reducing the reflectivity of the coating and improving the thermal radiance and the heat dispersion of the coating.

The polyurethane is two-component catalytic moisture-curing polyurethane, wherein the mass ratio of the catalyst to the prepolymer is 2-4: 100. The catalyst is one of anhydrous xylene solution, dimethylethanolamine solution, xylene solution and methyldiethanolamine solution containing 5% dimethylethanolamine.

The titanium oxide is rutile phase and/or anatase phase nano titanium oxide, and the particle size is 20-100 nm; preferably, the titanium oxide is P25 titanium dioxide, most of which contains a small amount of rutile phase in anatase phase, has good light absorption property in the ultraviolet and visible light range, and contributes to radiation of a small amount of generated heat in the wavelength range.

The foaming agent comprises any one or more of azoaminobenzene, p-toluenesulfonyl hydrazide and 3, 3' -disulfonyl hydrazide diphenyl sulfone.

The carbon powder is a nano carbon material and comprises onion-shaped carbon powder and/or multi-wall carbon nano tubes; the particle size of the onion-shaped carbon powder is 5-100 nm, the outer diameter of the multi-walled carbon nano tube is 5-40 nm, the tube length is 5-50 mu m, and when nano carbon powder with different particle sizes and tube diameters enters light waves with different wavelengths, light paths in the nano carbon powder are subjected to multiple refraction and reflection, diffuse reflection and multiple absorption. The smaller the particle size, the larger the specific surface area, the more the light waves with different wavelengths are refracted and reflected inside, the more the absorption times, and the final macroscopic expression is that the thermal radiance is increased.

The carbon powder is subjected to surface reduction treatment. The pure nano carbon powder without any modification has no or only a small absorption peak in an infrared spectrogram, but can generate a strong absorption peak in an infrared section such as 2.5-10 mu m after surface clustering, so that the radiance of the coating is greatly improved.

The method for the surface reduction treatment comprises the following steps: treating the mixture for 1 to 5 hours at 300 to 500 ℃ under the condition that the flow of ammonia gas is 50 to 400sccm and the flow of ammonia gas is taken as a reducing atmosphere; the nano carbon powder containing nitrogen groups after surface treatment generates a stronger infrared absorption peak in a section of 2.5-10 mu m, so that the reflectivity of the coating can be reduced, and the radiation performance is improved.

The particle size of the silicon oxide is 10-100 nm, the particle size of the aluminum oxide is 10-100 nm, and the particle size of the ferric oxide is 10-150 nm. The specific surface area of the particles is influenced by the size of the particle size of the powder, the larger the specific surface area is, the stronger the light absorption is, but the larger the particle size is, the lower the binding force of the coating and the substrate is caused.

The curing agent comprises at least one of vinyl triamine, ethylene diamine, diaminocyclohexane, diethylenetriamine and dipropylenetriamine.

The invention also provides a preparation method of the high-radiation slurry, which comprises the steps of dispersing titanium oxide, metal oxide and carbon powder in polyurethane, stirring at a high speed for 4-10 h, adding a foaming agent, acrylic acid and a curing agent, and stirring at a high speed for 1-3 h to obtain the high-radiation slurry. The preparation method is simple to operate, does not need heating, has low requirements on equipment, and is easy for industrial production.

The invention also provides application of the high-emissivity slurry as a coating, wherein the high-emissivity slurry is coated on a substrate, the deposition thickness is 20-500 mu m, and the coating with high emissivity is obtained by naturally airing or drying. The coating can reach more than 0.95 at the wave band with the thermal radiance of 2.5-18 mu m, and has excellent thermal radiation performance.

The coating can adopt the processes of spraying, brushing and the like, and the coating is naturally dried for one day or is dried for 2-4 hours in an oven at the temperature of 100-200 ℃.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, the surface modification of the carbon material is regulated and controlled, and the inorganic organic compounds with different light absorption performance under different wave bands are combined, so that the light absorption rate of near infrared middle and far infrared wave bands is comprehensively improved, the reflectivity of the coating is further reduced, and the radiation heat dispersion of the coating is improved.

(2) The preparation method of the high-radiation slurry is simple, low in production cost, low in equipment requirement and easy for industrial production.

(3) The coating prepared by the slurry disclosed by the invention is firmly bonded with the substrate, and the surface of the coating is free of bubbles and cracks. The thermal radiance of the coating can reach more than 0.95 at the wave band of 2.5-18 mu m, has excellent thermal radiation performance, and can play a good role in heat dissipation in some special application environments.

Drawings

FIG. 1 is a graph of the temperature difference between the coating and the substrate in example 1.

FIG. 2 is a graph comparing the emissivity of the substrate and the coating of example 2.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Those skilled in the art should understand that they can make modifications and equivalents without departing from the spirit and scope of the present invention, and all such modifications and equivalents are intended to be included within the scope of the present invention.

Example 1

In the embodiment, the mass ratio of each raw material component is as follows: 30 wt.% of polyurethane (wherein the catalyst is an anhydrous xylene solution containing 5% dimethylethanolamine, and the ratio of the prepolymer to the catalyst is 100: 2); titanium oxide powder 6 wt.%; acrylic acid 20 wt.%; 2 wt.% azoaminobenzene; carbon powder 2 wt.% (nano carbon powder is onion-shaped carbon with about 10 nm); 15 wt.% silica; 15 wt.% alumina; iron oxide 8 wt.%; vinyl triamine 2 wt.%.

The preparation method comprises the following steps: putting the onion-shaped nano carbon material into an atmosphere furnace, introducing 150sccm ammonia gas, heating the furnace to 400 ℃, carrying out constant temperature treatment for 2 hours, and naturally cooling for later use. And dispersing the nano silicon oxide powder, the nano titanium oxide powder, the nano iron oxide powder and the reduced onion-shaped carbon material in the polyurethane liquid in sequence according to a proportion, and stirring at a high speed of 4000rpm for 8 hours. After 8 hours azoaminobenzene, acrylic acid and vinyl triamine were added and stirring was continued for 1 hour at 4000 rpm. And depositing the slurry on an aluminum-based heat dissipation sheet in a liquid material spraying manner, and naturally airing for one day to obtain a coating with high radiance. The temperature difference of the coating surface is measured by a measuring method, and the result is shown in figure 1, and the difference between the coating piece and the original piece can be more than 10 ℃ within 30 minutes, which indicates that the coating piece has good heat dissipation effect.

Example 2

In the embodiment, the mass ratio of each raw material component is as follows: 40 wt.% of polyurethane (wherein the catalyst is an anhydrous xylene solution containing 5% dimethylethanolamine, and the ratio of the prepolymer to the catalyst is 100: 4); titanium oxide 10 wt.%; acrylic acid 20 wt.%; 1 wt.% p-toluenesulfonyl hydrazide; 1 wt.% of carbon powder (the carbon nano-tube is selected from carbon nano-tubes, the diameter is about 10nm, and the length of the tube is 25 μm); 10 wt.% silica; 15 wt.% alumina; diaminocyclohexane 3 wt.%.

The preparation method comprises the following steps: putting the carbon nano tube into an atmosphere furnace, introducing 250sccm ammonia gas, heating the furnace to 500 ℃, carrying out constant temperature treatment for 1 hour, and naturally cooling for later use. And dispersing the silicon oxide, the aluminum oxide, the titanium oxide and the carbon nano tube subjected to reduction treatment in the polyurethane liquid in sequence according to a ratio, and stirring at a high speed for 10 hours at the rotating speed of 4000 rpm. After 10 hours p-toluenesulfonyl hydrazide was added, and the acrylic acid and diaminocyclohexane were stirred at 4000rpm for an additional 2 hours. And depositing the slurry on a stainless steel substrate in a liquid material spraying manner, putting the stainless steel substrate into a drying box, and drying for 2 hours at the temperature of 200 ℃. The emissivity of the substrate and the coating is calculated by kirchhoff's law, and as shown in fig. 2, the emissivity of the substrate is 0.44, the emissivity of the coating member is 0.95 at 25 ℃, and the emissivity of the coating member is as high as 0.96 at 85 ℃ and 100 ℃.

Example 3

In the embodiment, the mass ratio of each raw material component is as follows: 15 wt.% of polyurethane (wherein the catalyst is an anhydrous xylene solution containing 5% dimethylethanolamine, and the ratio of the prepolymer to the catalyst is 100: 3); titanium oxide 5 wt.%; acrylic acid 40 wt.%; 1 wt.% azoaminobenzene; carbon powder 4 wt.% (carbon nano-tube with diameter of about 5nm and length of 40 μm is selected as nano-carbon powder); silica 4 wt.%; 20 wt.% alumina; iron oxide 10 wt.%; ethylenediamine 1 wt.%.

The preparation method comprises the following steps: putting the carbon nano tube into an atmosphere furnace, introducing ammonia gas of 400sccm, heating the furnace to 300 ℃, carrying out constant temperature treatment for 5 hours, and naturally cooling for later use. And dispersing the silicon oxide, the aluminum oxide, the iron oxide and the titanium oxide in the polyurethane liquid in sequence, wherein the carbon nano tubes are subjected to reduction treatment in proportion, and stirring at a high speed of 4000rpm for 8 hours. After 8 hours azoaminobenzene, acrylic acid and ethylenediamine were added and stirring was continued for 2 hours at 4000 rpm. And depositing the slurry on a stainless steel substrate in a liquid material spraying manner, putting the stainless steel substrate into a drying box, and drying for 4 hours at the temperature of 100 ℃. The emissivity of the substrate was 0.45 calculated by kirchhoff's law, the emissivity of the coated article was 0.93 at 25 ℃ and the emissivity of the coated article was 0.94 at 85 ℃ and 100 ℃.

Example 4

In the embodiment, the mass ratio of each raw material component is as follows: 30 wt.% of polyurethane (wherein the catalyst is an anhydrous xylene solution containing 5% dimethylethanolamine, and the ratio of the prepolymer to the catalyst is 100: 2); titanium oxide 5 wt.%; acrylic acid 10 wt.%; 3 wt.% azoaminobenzene; 5 wt.% carbon powder (the nano carbon powder is onion-shaped carbon with the particle size of about 50 nm); 7 wt.% silica; 15 wt.% alumina; iron oxide 20 wt.%; 1 wt.% vinyl triamine.

The preparation method comprises the following steps: putting the carbon nano tube into an atmosphere furnace, introducing 200sccm ammonia gas, heating the furnace to 400 ℃, carrying out constant temperature treatment for 2 hours, and naturally cooling for later use. And dispersing the silicon oxide, the aluminum oxide, the iron oxide and the titanium oxide in the polyurethane liquid in sequence, wherein the carbon nano tubes are subjected to reduction treatment in proportion, and stirring at a high speed of 4000rpm for 8 hours. After 8 hours azoaminobenzene, acrylic acid and vinyl triamine were added and stirring was continued for 2 hours at 4000 rpm. And depositing the slurry on an aluminum-based heat dissipation sheet in a liquid material spraying mode, and naturally airing for one day. The difference between the coating piece and the original piece can be over 7 ℃ within 30 minutes by adopting a measuring method, which shows that the coating piece has good heat dissipation effect.

Example 5

In the embodiment, the mass ratio of each raw material component is as follows: 40 wt.% of polyurethane (wherein the catalyst is an anhydrous xylene solution containing 5% dimethylethanolamine, and the ratio of the prepolymer to the catalyst is 100: 3); titanium oxide 10 wt.%; acrylic acid 20 wt.%; 1 wt.% azoaminobenzene; 2 wt.% of carbon powder (the carbon nano-tube is selected as the carbon nano-powder, the diameter is about 20nm, and the length of the tube is 20 μm); 15 wt.% alumina; iron oxide 10 wt.%; ethylenediamine 2 wt.%.

The preparation method comprises the following steps: putting the carbon nano tube into an atmosphere furnace, introducing 200sccm ammonia gas, heating the furnace to 300 ℃, carrying out constant temperature treatment for 2 hours, and naturally cooling for later use. And sequentially dispersing the aluminum oxide, the iron oxide and the titanium oxide in the polyurethane liquid according to the proportion, and stirring at a high speed for 8 hours at the rotating speed of 4000 rpm. After 8 hours azoaminobenzene, acrylic acid and ethylenediamine were added and stirring was continued for 2 hours at 4000 rpm. And depositing the slurry on a stainless steel substrate in a liquid material spraying manner, putting the stainless steel substrate into a drying box, and drying for 4 hours at the temperature of 100 ℃. The emissivity of the substrate is 0.43 calculated by kirchhoff's law, the emissivity of the coating member is 0.95 at 25 ℃, and the emissivity of the coating member is 0.96 at 85 ℃ and 100 ℃.

Example 6

In the embodiment, the mass ratio of each raw material component is as follows: 40 wt.% of polyurethane (wherein the catalyst is an anhydrous xylene solution containing 5% dimethylethanolamine, and the ratio of the prepolymer to the catalyst is 100: 3); titanium oxide 10 wt.%; acrylic acid 20 wt.%; 1 wt.% azoaminobenzene; 2 wt.% of carbon powder (the carbon nano-tube is selected as the carbon nano-powder, the diameter is about 20nm, and the length of the tube is 20 μm); 15% of aluminum oxide and about 30nm of powder diameter; 10 wt.% of iron oxide and the diameter of the powder is about 15 nm; vinyl triamine 2 wt.%.

The preparation method comprises the following steps: putting the carbon nano tube into an atmosphere furnace, introducing 200sccm ammonia gas, heating the furnace to 400 ℃, carrying out constant temperature treatment for 2 hours, and naturally cooling for later use. And dispersing the silicon oxide, the aluminum oxide, the iron oxide and the titanium oxide in the polyurethane liquid in sequence, wherein the carbon nano tubes are subjected to reduction treatment in proportion, and stirring at a high speed of 5000rpm for 8 hours. After 8 hours azoaminobenzene, acrylic acid and vinyl triamine were added and stirring was continued for 2 hours at 5000 rpm. And (3) brushing the slurry on a plastic substrate according to a spin coating mode, putting the plastic substrate into a drying box, and drying for 4 hours at the temperature of 100 ℃. The difference between the coating piece and the original piece can be more than 8 ℃ within 30 minutes by adopting a temperature difference measurement method, which indicates that the coating piece has good heat dissipation effect.

Comparative example 1

The mass ratio of each raw material component in the comparative example is as follows: 40 wt.% of polyurethane (wherein the catalyst is an anhydrous xylene solution containing 5% dimethylethanolamine, and the ratio of the prepolymer to the catalyst is 100: 3); titanium oxide 10 wt.%; acrylic acid 20 wt.%; 1 wt.% azoaminobenzene; carbon powder 2 wt.% (fullerene-like carbon nanospheres around 10 nm); 15 wt.% alumina; iron oxide 10 wt.%; ethylenediamine 2 wt.%.

The preparation method comprises the following steps: and sequentially dispersing alumina, iron oxide, titanium oxide and nano carbon powder in the polyurethane liquid according to a proportion, and stirring at a high speed for 8 hours at the rotating speed of 4000 rpm. After 8 hours azoaminobenzene, acrylic acid and ethylenediamine were added and stirring was continued for 2 hours at 4000 rpm. And depositing the slurry on a stainless steel substrate in a liquid material spraying manner, putting the stainless steel substrate into a drying box, and drying for 4 hours at the temperature of 100 ℃. The emissivity of the substrate was 0.43 as calculated by kirchhoff's law, the emissivity of the coated article was 0.87 at 25 c, and the emissivity of the coated article was 0.89 at 85 c and 100 c.

Comparative example 2

The mass ratio of each raw material component in the comparative example is as follows: 40 wt.% of polyurethane (wherein the catalyst is an anhydrous xylene solution containing 5% dimethylethanolamine, and the ratio of the prepolymer to the catalyst is 100: 3); acrylic acid 20 wt.%; 1 wt.% azoaminobenzene; carbon powder 2 wt.% (fullerene-like carbon nanospheres around 10 nm); 15 wt.% alumina; iron oxide 20 wt.%; ethylenediamine 2 wt.%.

The preparation method comprises the following steps: and sequentially dispersing alumina, ferric oxide and nano carbon powder in the polyurethane liquid according to a proportion, and stirring at a high speed of 4000rpm for 8 hours. After 8 hours azoaminobenzene, acrylic acid and ethylenediamine were added and stirring was continued for 2 hours at 4000 rpm. And depositing the slurry on a stainless steel substrate in a liquid material spraying manner, putting the stainless steel substrate into a drying box, and drying for 4 hours at the temperature of 100 ℃. The emissivity of the substrate was calculated to be 0.43 using kirchhoff's law, 0.81 for the coated article at 25 c, and 0.83 for the coated article at 85 c and 100 c. Compared with the embodiment that the heat dissipation effect of the coating is not ideal, the emissivity is lower.

Claims

1. The high-radiation slurry is characterized by comprising the following raw material components in percentage by mass:

the metal oxide comprises one or more of silicon oxide, aluminum oxide and iron oxide.

2. The high-radiation slurry according to claim 1, wherein the titanium oxide is rutile phase and/or anatase phase nano titanium oxide, and the particle size is 20-100 nm.

3. The high radiation slurry of claim 1, wherein the foaming agent comprises any one or more of azoaminobenzene, p-toluenesulfonyl hydrazide, 3, 3' -disulfonyl hydrazide diphenyl sulfone.

4. The high-radiation slurry according to claim 1, wherein the carbon powder is a nano carbon material comprising onion-shaped carbon powder and/or multi-walled carbon nanotubes; wherein the particle diameter of the onion-shaped carbon powder is 5-100 nm, the outer diameter of the multi-walled carbon nano tube is 5-40 nm, and the tube length is 5-50 mu m.

5. The high-emissivity paste of claim 1 or 4, wherein the carbon powder is subjected to surface reduction treatment.

6. The high-emissivity paste of claim 5, wherein the surface reduction treatment is performed by using ammonia gas as a reducing atmosphere, wherein the ammonia gas is at a flow rate of 50sccm to 400sccm and is treated at 300 ℃ to 500 ℃ for 1 to 5 hours.

7. The high-radiation slurry according to claim 1, wherein the silicon oxide has a particle size of 10 to 100nm, the aluminum oxide has a particle size of 10 to 100nm, and the iron oxide has a particle size of 10 to 150 nm.

8. The high radiation paste according to claim 1, wherein the curing agent comprises at least one of vinyl triamine, ethylene diamine, diaminocyclohexane, diethylene triamine, and dipropylene triamine.

9. The preparation method of the high-radiation slurry according to any one of claims 1 to 8, characterized by dispersing titanium oxide, metal oxide and carbon powder in polyurethane, stirring at a high speed for 4-10 h, adding a foaming agent, acrylic acid and a curing agent, and stirring at a high speed for 1-3 h to obtain the high-radiation slurry.

10. The application of the high-radiation slurry as a coating according to any one of claims 1 to 8, wherein the high-radiation slurry is coated on a substrate, deposited to a thickness of 20 to 500 μm, and naturally dried or baked to obtain the coating with high radiation rate.