阅读说明：本技术 一种多孔吸收涂层及其制备方法 (Porous absorption coating and preparation method thereof ) 是由 朱丽慧 何志聪 黄颖璞 于 2020-12-15 设计创作，主要内容包括：本发明涉及太阳能吸收涂层,特指一种多孔吸收涂层及其制备方法。本发明将不同形状的无机填料与树脂溶剂混合均匀得到混合溶液,采用高压静电喷涂技术将制备的混合溶液制备为多孔吸收涂层。在喷涂过程中,无机填料带相同电荷,产生相互排斥的作用,形成均匀多孔的涂层,多孔的结构可对光起到多次内反射作用,而纳米颗粒以及管会引起光散射效应,增大了光在涂层内的传播路径,由此提高涂层的吸收性能。(The invention relates to a solar energy absorbing coating, in particular to a porous absorbing coating and a preparation method thereof. The invention mixes inorganic fillers with different shapes and resin solvent evenly to obtain mixed solution, and prepares the prepared mixed solution into the porous absorption coating by adopting high-voltage electrostatic spraying technology. In the spraying process, the inorganic filler is charged the same to generate mutual repulsion action to form a uniform porous coating, the porous structure can play a role in multiple internal reflection of light, and the nano particles and the tube can cause a light scattering effect to increase the propagation path of the light in the coating, so that the absorption performance of the coating is improved.)

1. A preparation method of a porous absorption coating is characterized by comprising the following specific steps:

step 1: weighing three or more than three inorganic fillers according to the proportion;

step 2: adding two or three weighed inorganic fillers into a dispersing agent one by one, and performing mechanical stirring and ultrasonic dispersion to form a powder solution;

and step 3: adding the rest inorganic filler into the dispersed powder solution in a solution form, and performing mechanical stirring and ultrasonic dispersion again to form dispersed slurry;

and 4, step 4: dispersing a resin solvent in an organic solvent, mechanically stirring until the resin solvent is completely dissolved, and standing for a period of time to form a uniformly dispersed resin solution;

and 5: mixing the slurry and the resin solution according to a certain proportion, and mechanically stirring uniformly to obtain a mixed solution;

step 6: sucking the mixed solution to a spraying gun, adjusting the spraying height, the spraying voltage and the spraying speed, and spraying on a workpiece cleaned in advance;

and 7: and (3) putting the sprayed workpiece into an oven, baking for a certain time at a certain temperature, taking out and cooling.

2. The method for preparing a porous absorption coating according to claim 1, wherein in step 1, the different types of inorganic fillers are added in the same mass; the inorganic filler is RG, CMP, CNP, CNT or TiN; the sizes of graphene (RG) and carbon micro-particles (CMP) were both 500nm, the particle sizes of Carbon Nanoparticles (CNP) and TiN nanoparticles were both 20nm, and the diameter of Carbon Nanotubes (CNT) was about 10 nm.

3. The method for preparing a porous absorption coating according to claim 1, wherein in the step 2, the mass ratio of the inorganic filler to the dispersant is 1: 7-1: 13, the dispersant is Tianna water.

4. The method for preparing a porous absorption coating according to claim 1, wherein in the step 4, the mass ratio of the resin solvent to the organic solvent is 1:1, the organic solvent is Tianna water, and the resin solvent is solvent-type acrylic resin.

5. The method for preparing a porous absorption coating according to claim 1, wherein the mass ratio of the slurry to the resin solution in step 5 is 6.75: 1.

6. The method for preparing a porous absorption coating according to claim 1, wherein in step 6, the thickness of the pre-coating is controlled to be 6 to 10 μm.

7. The method for preparing a porous absorption coating according to claim 1, wherein in step 7, the baking temperature is 110 ℃ and the baking time is 30 min.

Technical Field

The invention relates to a solar energy absorbing coating, in particular to a porous absorbing coating and a preparation method thereof.

Background

It is known that fossil fuels such as oil, natural gas and coal are non-renewable energy sources, and the combustion of these fossil fuels causes serious pollution to the environment. Therefore, it is necessary to replace fossil fuels with new energy, and solar energy is an inexhaustible green and environment-friendly energy, so that the research of converting solar energy into heat energy has important significance.

Among solar thermal technologies, concentrated solar technology is one of the most mature technologies, and solar absorptive coatings play an irreplaceable role in concentrated solar technology. The absorption effect of the solar energy absorption coating on sunlight directly influences the efficiency of converting solar energy into heat energy, so that the coating with high absorption rate on the sunlight in a wide waveband range is obtained. Until now, there have been many studies on solar absorptive coatings, but most of them are in the narrow band range (1000nm band) and can only reach absorption around 90%.

At present, the preparation method of the solar energy absorption coating mainly comprises the following steps: magnetron sputtering, electrochemical deposition, sol-gel, paint coating, high-voltage electrostatic spraying, etc. The high-voltage electrostatic spraying method has the advantages of low cost, simple operation, easily controlled conditions, uniform coating, large-scale production, high production efficiency and the like. The principle is that according to the physical phenomenon of electrophoresis, a coated object is used as an anode and is generally grounded, a coating atomizing mechanism is used as a cathode, and a negative high voltage is connected with a power supply, so that a high-voltage electrostatic field is formed at the two electrodes. Because corona discharge is generated at the cathode, the sprayed coating medium can be charged and further atomized. According to the principle of 'like charges repel and opposite charges' the charged coating medium is acted by an electric field force, and flows directionally to the surface of the object to be coated, which is positively charged, along the direction of the electric field under the action of the electric field force.

Therefore, it is of great significance to prepare an absorptive coating having a high absorption rate in a wide wavelength band by a simple method.

Disclosure of Invention

The invention aims to provide a porous absorption coating and a preparation method thereof, and aims to provide a simple preparation method for obtaining the porous absorption coating with high absorption rate in the 200-1400nm waveband range.

In order to achieve the purpose, the invention discloses a porous absorption coating and a preparation method thereof. In the inorganic filler, the sizes of graphene (RG) and Carbon Microparticles (CMP) are both 500nm, the particle diameters of Carbon Nanoparticles (CNP) and TiN nanoparticles are both 20nm, the diameter of Carbon Nanotubes (CNT) is about 10nm, and the resin solvent is solvent-type acrylic resin. The volume of the spray gun is 5 mul, the spray voltage is 10kv, the spray height is 2cm, the spray rate is 1 mul/min, and the spray time is 5 min.

The preparation method of the porous absorption coating is characterized by comprising the following specific preparation steps:

step 1: three or more inorganic fillers are weighed according to the proportion.

Step 2: and adding two or three weighed inorganic fillers into the dispersing agent one by one, and performing mechanical stirring and ultrasonic dispersion to form a powder solution.

And step 3: and adding the rest inorganic filler into the dispersed powder solution in a solution form, and performing mechanical stirring and ultrasonic dispersion again to form dispersed slurry.

And 4, step 4: dispersing the resin in an organic solvent, mechanically stirring until the resin is completely dissolved, and standing for a period of time to form a uniformly dispersed resin solution.

And 5: and mixing the slurry and the resin solution according to a certain proportion, and mechanically stirring uniformly to obtain a mixed solution.

Step 6: and (4) sucking the mixed solution to a spraying gun, adjusting the spraying height, the spraying voltage and the spraying speed, and spraying on the workpiece cleaned in advance.

And 7: and (3) putting the sprayed workpiece into an oven, baking for a certain time at a certain temperature, taking out and cooling.

In the step 1, the adding quality of different types of inorganic fillers is the same; the inorganic filler is RG, CMP, CNP, CNT or TiN.

The mass ratio of the inorganic filler to the dispersant is 1: 7-1: 13, the dispersant is Tianna water.

In the step 4, the mass ratio of the resin solvent to the organic solvent is 1:1, and the organic solvent is Tiana water.

In step 5, the mass ratio of the slurry to the resin solution was 6.75: 1.

In the step 6, the thickness of the prefabricated coating is controlled to be 6-10 mu m.

In step 7, the baking temperature is 110 ℃ and the baking time is 30 min.

Compared with the prior art, the invention has the following advantages: (1) inorganic fillers with different particle sizes, sizes and materials are added, so that a porous coating with high absorption in a wider wave band range can be obtained; (2) epoxy resin with high strength, high modulus, low shrinkage, high adhesion and excellent chemical corrosion resistance is selected as a binder of the coating, so that the prepared absorption coating has good thermal stability and weather resistance; (3) the high-voltage electrostatic spraying technology is adopted, the process is simple, the process conditions are easy to control, and the production cost can be obviously reduced.

Drawings

FIG. 1 is a graph showing the absorption spectrum and the average absorption rate of the porous absorption coating in 200-1400 nm; (a) the RG/CNT-CNP-TiN porous absorption coating, the CNT/CNP-TiN porous absorption coating and the CMP/CNT-CNP-TiN porous absorption coating are sequentially arranged from bottom to top; (b) the absorbance at 200-1400nm for examples 1-3.

Fig. 2 is a microstructure view of a porous absorbent coating.

Wherein (a) and (a') are RG/CNT-CNP-TiN porous absorption coatings. (b) And (b') is a CMP/CNT-CNP-TiN porous absorption coating. (c) And (c') is a CNT/CNP-TiN porous absorption coating.

Detailed Description

The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.

Preparation example 1

The general preparation procedure for the coating structure of fig. 1 in the present invention is:

step 1: weighing 0.25g of TiN particles with the particle size of 20 nm; weighing 0.25g of CNP particles with the particle size of 20 nm;

step 2: pouring the weighed powder into a beaker filled with 13g of dispersant, magnetically stirring for 30min, and then ultrasonically dispersing for 30min until the powder is uniformly dispersed to form a powder solution.

And step 3: weighing 6.25g of graphene solution (RG) with the mass fraction of 4% in a beaker, wherein the size of the graphene is 500 nm; then 6.25g of carbon nanotube solution (CNT) with the mass fraction of 4% is weighed in a beaker, and the diameter of the carbon nanotube is 10 nm; magnetically stirring for 30min, and ultrasonically dispersing for 30min to obtain uniformly dispersed slurry.

And 4, step 4: dispersing 1g of solvent type acrylic resin in 1g of organic solvent, wherein the organic solvent is Tianna water, magnetically stirring for 30min until the solvent type acrylic resin is completely dissolved, and standing for 30min to form a uniformly dispersed resin solution.

And 5: mixing the dispersed slurry obtained in the step 3 with the uniformly dispersed resin solution according to the mass ratio of 6.75:1, and continuously stirring for 30min until the slurry and the resin solution are completely mixed to obtain a mixed solution;

step 6: ultrasonically cleaning an aluminum plate in an ethanol solution for 15min, taking out and drying the aluminum plate for later use;

and 7: sucking 5 mul of the mixed solution to a spraying gun, adjusting the spraying height to 2cm, adjusting the spraying voltage to 10kv, controlling the spraying speed to be 1 mul/min and the spraying time to be 5 min.

And 8: and (3) putting the sprayed substrate into an oven, and baking for 30min at 110 ℃.

Preparation example 2

The general preparation procedure for the coating structure of fig. 1 in the present invention is:

step 1: weighing 0.25g of TiN particles with the particle size of 20 nm; weighing 0.25g of CNP particles with the particle size of 20 nm;

then 0.25g of CMP particles with the particle size of 500nm are weighed;

step 2: pouring the weighed powder into a beaker filled with 7g of dispersant, magnetically stirring for 30min, and then ultrasonically dispersing for 30min until the powder is uniformly dispersed to form a powder solution.

And step 3: then 6.25g of carbon nanotube solution (CNT) with the mass fraction of 4% is weighed in a beaker, and the diameter of the carbon nanotube is 10 nm; magnetically stirring for 30min, and ultrasonically dispersing for 30min to obtain uniformly dispersed slurry.

And 4, step 4: dispersing 1g of solvent type acrylic resin in 1g of organic solvent, wherein the organic solvent is Tianna water, magnetically stirring for 30min until the solvent type acrylic resin is completely dissolved, and standing for 30min to form a uniformly dispersed resin solution;

and 5: mixing the dispersed slurry obtained in the step 3 with the uniformly dispersed resin solution according to the mass ratio of 6.75:1, and continuously stirring for 30min until the slurry and the resin solution are completely mixed to obtain a mixed solution;

step 6: ultrasonically cleaning an aluminum plate in an ethanol solution for 15min, taking out and drying the aluminum plate for later use;

and 7: sucking 5 mul of the mixed solution to a spraying gun, adjusting the spraying height to 2cm, adjusting the spraying voltage to 10kv, controlling the spraying speed to be 1 mul/min and the spraying time to be 5 min.

And 8: and (3) putting the sprayed substrate into an oven, and baking for 30min at 110 ℃.

Preparation example 3

The general preparation procedure for the coating structure of fig. 1 in the present invention is:

step 1: weighing 0.25g of TiN particles with the particle size of 20 nm; weighing 0.25g of CNP particles with the particle size of 20 nm; step 2: pouring the weighed powder into a beaker filled with 6.75g of dispersant which is Tianna water, magnetically stirring for 30min, and then ultrasonically dispersing for 30min until the powder is uniformly dispersed to form a powder solution.

And step 3: then 6.25g of carbon nanotube solution (CNT) with the mass fraction of 4% is weighed in a beaker, and the diameter of the carbon nanotube is 10 nm; magnetically stirring for 30min, and ultrasonically dispersing for 30min to obtain uniformly dispersed slurry.

And 4, step 4: dispersing 1g of solvent type acrylic resin in 1g of organic solvent, wherein the organic solvent is Tianna water, magnetically stirring for 30min until the solvent type acrylic resin is completely dissolved, and standing for 30min to form a uniformly dispersed resin solution;

and 5: mixing the dispersed slurry obtained in the step 3 with the uniformly dispersed resin solution according to the mass ratio of 6.75:1, and continuously stirring for 30min until the slurry and the resin solution are completely mixed to obtain a mixed solution;

step 6: ultrasonically cleaning an aluminum plate in an ethanol solution for 15min, taking out and drying the aluminum plate for later use;

and 7: sucking 5 mul of the mixed solution to a spraying gun, adjusting the spraying height to 2cm, adjusting the spraying voltage to 10kv, controlling the spraying speed to be 1 mul/min and the spraying time to be 5 min.

And 8: and (3) putting the sprayed substrate into an oven, and baking for 30min at 110 ℃.

Example 1

According to the RG/CNT-CNP-TiN porous absorption coating prepared by the method in the preparation example 1, in the high-voltage electrostatic spraying process, RG in epoxy resin slurry is charged with the same kind of charges to generate mutual repulsion, graphene sheets are stacked to form a porous framework, meanwhile, a part of CNT, CNP nano-particles and nano TiN particles are attached to the surfaces of the graphene sheets to provide multiple reflection and scattering of light to a certain degree, and a part of CNT, CNP nano-particles and nano TiN particles are embedded among the graphene sheets to improve the porosity of the graphene framework and optimize the spatial structure of the coating. However, the formed graphene skeleton has low porosity, and the graphene is a bright sheet and has a reflection effect on light, so that the coating still has a large optimization space, and the absorption rate of the RG/CNT-CNP-TiN porous absorption coating disclosed in this embodiment 1 at 200-1400nm can reach 93.4%.

Example 2

According to the CMP/CNT-CNP-TiN porous absorption coating prepared by the method of the preparation example 2, in the high-voltage electrostatic spraying process, CMP particles in epoxy resin slurry carry the same charges to generate mutual repulsion action to form a porous framework, and CMP is adopted as the framework of the coating to enable the coating to have a better spatial structure; meanwhile, the slender carbon nanotubes and the nanoparticles form a honeycomb-shaped fine porous structure mutually and are attached to the CMP porous skeleton, so that the porosity of the coating is improved, and the light capturing capacity of the coating is increased, so that the coating can obtain excellent absorption performance. The absorption rate of the CMP/CNT-CNP-TiN porous absorption coating disclosed in the embodiment 2 at the position of 200-1400nm can reach 96.8%.

Example 3

According to the CNT/CNP-TiN porous absorption coating prepared by the method of the preparation example 3, in the high-voltage electrostatic spraying process, a porous reticular skeleton is formed among CNTs in epoxy resin slurry, and compared with the skeleton formed by RG and CMP, the porosity of the CNT skeleton is higher and the holes are smaller; meanwhile, CNP and TiN nano-particles are embedded into the reticular CNT skeleton to form a honeycomb-like structure, so that the function of supporting the CNT skeleton is achieved, the spatial structure of the coating is optimized, and the coating has better light capturing capacity. The absorption rate of the CNT/CNP-TiN porous absorption coating disclosed in the embodiment 3 at 200-1400nm can reach 97.1%.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.