Inorganic super-black light-absorbing powder with multi-stage structure, and preparation method and application thereof

Abstract

The application discloses a kind of super black light-absorbing powder and its preparation method and application, belong to super black powder and its preparation technical field.The application utilizes the adsorption of carbon black, and grows hydroxide on carbon black, then carries out calcination treatment, obtains the super black light-absorbing powder of carbon black loaded spinel oxide multi-stage light-absorbing structure.The powder prepared by the application has the special hierarchical structure, which reduces surface light scattering, promotes the absorption of stray light, and has good local plasmon resonance effect under sunlight irradiation.In addition, the application provides a simple preparation process for super black light-absorbing powder, little environmental pollution, easy to produce, and the preparation cost is relatively low, and the copper chromium black pigment prepared has high purity, uniform particles, complete crystal form, has great market advantage.The powder has good dispersing performance in water-based resin, avoids uneven dispersion and sinking of the coating, improves the concentration of the surface coating of the prepared coating, and improves the light-absorbing performance of the coating.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of super black light-absorbing powder and its preparation method and application, belong to super black powder and its preparation technical field. BACKGROUND

[0002] With the continuous development of China's space technology, stray light as the non-imaging light reaching the optical system image plane, its existence can form system noise interference to star sensor, space camera, spectrometer and other space optical load, reduce their detection signal-to-noise ratio, sensitivity and inversion accuracy, etc., in serious cases, it will be weak target signal. Stray light coating (stray light coating) can be used in space environment by itself to realize the absorption and weakening of non-imaging sensitive light in the optical detector light path with high absorption rate at specific wavelength, so as to suppress stray light.

[0003] Copper-chromium black (CuCr2O4) pigment is a kind of metal oxide mixed phase pigment with spinel crystal structure. By adding copper-chromium black pigment into resin to prepare light-absorbing coating, copper-chromium black pigment is used to absorb stray light, so as to realize the suppression of stray light. Because copper-chromium black (CuCr2O4) pigment has excellent chemical stability, heat resistance, light resistance, weather resistance, acid and alkali resistance, chemical resistance and other advantages, it has attracted people's attention.

[0004] The traditional preparation method of copper-chromium black mainly includes solid phase method and liquid phase method. The traditional solid phase method for preparing copper-chromium black has the following problems: (1) since the raw material is solid, even if it is mixed by grinding for a long time, it is not uniform, which leads to small contact area of reaction particles, low reaction activity, uneven and insufficient reaction; (2) in order to make the reaction sufficient and uniform, the required reaction temperature is high, generally about 1200℃, which has high energy consumption and causes serious color agent caking, coarse particles and uneven distribution; (3) in order to meet the particle size requirements of application, it often needs to be ground again, which easily causes lattice damage, brings impurities and reduces chemical resistance. Generally speaking, the copper-chromium black pigment prepared by traditional liquid phase method is better than that prepared by traditional solid phase method in terms of purity and uniformity. However, the traditional liquid phase method for preparing copper-chromium black also has the following disadvantages: high requirement for raw materials, complex process, high temperature and high pressure are often required, high requirement for equipment, long reaction time, high production cost, secondary pollution, which is not conducive to industrial production. In addition, the obtained copper-chromium black pigment is easy to settle, has low pigment utilization rate and poor stray light elimination performance. Therefore, it is necessary to provide a kind of copper-chromium black super black light-absorbing powder with simple process, small environmental pollution, easy production and better light absorption performance. SUMMARY

[0005] In order to solve the above technical problems in the prior art, the present application provides a kind of super black light-absorbing powder and its preparation method and application.

[0006] The technical scheme of the present application:

[0007] One of the purposes of the present application is to provide a preparation method of super-black light-absorbing powder, which comprises the following steps:

[0008] (1) After mixing Cu(NO3)2 and Cr(NO3)3 according to the proportion, deionized water is added to obtain a reaction solution, then carbon black is added to the reaction solution, and after being fully dispersed, a metal salt glue solution is obtained;

[0009] (2) NaOH is added to the metal salt glue solution, and after being stirred uniformly, centrifugation, washing and drying are carried out to obtain carbon black loaded metal particles, which are recorded as Cu(OH)2 / Cr(OH)3@C;

[0010] (3) The Cu(OH)2 / Cr(OH)3@C is placed in a covered reaction dish, and then the whole is placed in a muffle furnace for calcination treatment to obtain carbon black loaded with spinel oxide, which is super-black light-absorbing powder, recorded as CuCr2O4@C.

[0011] Further limitation, the molar ratio of Cu(NO3)2 and Cr(NO3)3 in (1) is 1:2.

[0012] Further limitation, the molar and mass ratio of Cu(NO3)2, Cr(NO3)3 and carbon black in (1) is 26mmol:52mmol:1.776g.

[0013] Further limitation, the amount of deionized water added in (1) is 200mL.

[0014] Further limitation, the molar ratio of NaOH to Cr(NO3)3 added dropwise in (2) is 5:1.

[0015] Further limitation, after adding NaOH to the metal salt glue solution in (2), stirring for 30min.

[0016] Further limitation, the drying temperature in (2) is 60℃.

[0017] Further limitation, the calcination temperature in (3) is 300℃, and the calcination time is 4h.

[0018] The second purpose of the present application is to provide a super-black light-absorbing powder prepared by the above method, which is a carbon black loaded CuCr2O4 powder with a multi-level structure.

[0019] The third purpose of the present application is to provide an application of the above super-black light-absorbing powder, specifically, the super-black light-absorbing powder is compounded with water-based resin to prepare a coating layer with light-absorbing performance.

[0020] Beneficial effects:

[0021] The application synthesizes hydroxide Cu(OH)2 / Cr(OH)3 supported on carbon black (Cu(OH)2 / Cr(OH)3@C) at room temperature by a coprecipitation method, and then prepares a hierarchical structure of carbon black supported spinel super black light absorbing powder (CuCr2O4@C) through calcination. Compared with the prior art, the application has the following beneficial effects:

[0022] (1) The application utilizes the adsorption of carbon black to grow hydroxide on the carbon black, and then performs calcination treatment to obtain a powder of a multi-level light absorbing structure of carbon black supported spinel oxide. The preparation process provided by the application is simple, has little environmental pollution, is easy to produce, and has a relatively low preparation cost. The copper chromium black pigment prepared has high purity, uniform particles, and complete crystal form, and has great market advantages.

[0023] (2) The CuCr2O4@C powder prepared by the application has good dispersing performance in water-based resin, avoids uneven dispersion and sinking of the paint, improves the concentration of the surface paint of the prepared coating, and improves the light absorbing performance of the coating.

[0024] (3) The CuCr2O4@C black powder prepared by the application has a large surface area and excellent light absorbing performance. The special hierarchical structure reduces surface light scattering, promotes stray light absorption. Under sunlight irradiation, the copper chromium black pigment on the surface of the paint has a good local plasmon resonance effect, which promotes the absorption of the pigment to light. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A flowchart for preparing CuCr2O4@C according to the application;

[0026] Figure 2 A scanning electron microscope image of CuCr2O4@C prepared in Example 1;

[0027] Figure 3 An X-ray diffraction pattern of CuCr2O4@C prepared in Example 1;

[0028] Figure 4 A solar absorption spectrum of a CuCr2O4@C coating prepared in Example 1;

[0029] Figure 5 An emissivity graph of a CuCr2O4@C coating prepared in Example 1. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application will be described in detail below with reference to the embodiments of the application.

[0031] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details set forth in this description. In other instances, well-known methods have not been described in detail in order not to unnecessarily obscure aspects of the present application.

[0032] It is also noted that, as used herein, "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one implementation of the application. The appearances of the phrase "in one embodiment" or "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

[0033] The raw materials used in the embodiments are commercially available unless otherwise specified.

[0034] X-ray diffraction analysis (XRD): X-ray diffraction analysis was used to analyze the substance type and phase composition of CuCr2O4@C, to characterize its crystal structure and crystal defects. The excitation source was Cu target Kα ray, and the scanning range of the sample was 2θ = 10-80°.

[0035] Scanning electron microscope analysis (SEM): SEM was used to analyze the morphology and particle size of the prepared CuCr2O4@C. The scanning electron microscope was of the Merlin Compact type, produced by Carl Zeiss Company.

[0036] UV-Vis-NIR diffuse reflectance spectroscopy: A UV-Vis-NIR spectrophotometer (Lambda 950) with an integrating sphere accessory produced by Perkinelmer Company of the United States was used to test the UV-Vis-NIR diffuse reflectance spectra of different samples. When testing, the step size was set to 10 nm. First, a standard "white plate" made of BaSO4 was used to initialize the correction of the system with a reflectivity of 100%, so that the test results were more accurate. Then, the sample to be tested was fixed in the test window, and the reflectivity of different wavelengths of light was tested to obtain the UV-Vis-NIR diffuse reflectance spectrum in the range of 200-2500 nm.

[0037] Coating emissivity test: Fourier infrared spectrometer was used to test the infrared absorption rate of the sample to obtain the emissivity data of the coating.

[0038] Example 1

[0039] The process for preparing the super-black light-absorbing powder CuCr2O4@C in this embodiment is shown in Figure 1 The specific operation steps are as follows:

[0040] (1) Preparation of metal salt glue solution:

[0041] Cu(NO3)2 and 52 mmol of Cr(NO3)3 were dissolved in 200 mL of deionized water to form a uniform reaction solution. Then, 1.776 g of untreated carbon black was added to the reaction solution, stirred uniformly, and ultrasonically treated to obtain a metal salt glue solution.

[0042] (2) Preparation of Cu(OH)2 / Cr(OH)3@C:

[0043] To the metal salt glue solution obtained in step (1), 104 mmol of NaOH was further added to obtain a sol. The obtained sol was stirred for 30 min, and precipitation occurred to obtain Cu(OH)2 and Cr(OH)3 loaded on carbon black (Cu(OH)2 / Cr(OH)3@C), which was then centrifuged, washed with deionized water and ethanol three times each, and the precipitate was dried in a vacuum oven at a temperature of 60°C overnight.

[0044] (3) Preparation of CuCr2O4@C:

[0045] The obtained Cu(OH)2 / Cr(OH)3@C was placed in a covered reaction dish, and the whole was placed in a muffle furnace for calcination of the sample, with a calcination temperature of 300°C, a holding time of 4 h, and a temperature rising time of 30 min. Finally, spinel oxide CuCr2O4 loaded on carbon black was obtained, denoted as CuCr2O4@C.

[0046] The obtained super-black light-absorbing powder was subjected to microstructure characterization, and the surface SEM photograph thereof is shown in Figure 2 As can be seen from Figure 2 , the carbon black is in amorphous distribution, and the surface is loaded with copper-chromium black (shading), which proves that the multi-level light-absorbing structure of carbon black loaded with copper-chromium black is successfully prepared.

[0047] The obtained super-black light-absorbing powder was subjected to X-ray diffraction analysis, and the results are shown in Figure 3 As can be seen from Figure 3 , the XRD image of the prepared CuCr2O4@C shows three strong peaks of copper-chromium black, because the carbon black is amorphous and has no diffraction peak, and the diffraction peak of copper-chromium black is sharp and has no other impurity peak, which proves that the purity of CuCr2O4 loaded on the surface of carbon black in the obtained CuCr2O4@C powder is high, and the crystal form is complete.

[0048] (4) Preparation of CuCr2O4@C coating:

[0049] Take 7.4g of ultra-black light-absorbing powder CuCr2O4@C, mix it with 50g of aqueous potassium silicate resin with a mass fraction of 37% and 0.2g of magnesium aluminum silicate thickener, stir for 1 hour at a speed of 1000 rpm to obtain a sprayable black slurry, pour it into a spray gun, spray it onto an aluminum sheet under appropriate air pressure, and then cure it at 80℃ for 10 hours and at 120℃ for 2 hours respectively.

[0050] Dispersion performance: Compared with carbon black powder, CuCr2O4@C powder can be dispersed more easily in aqueous potassium silicate solution. Therefore, CuCr2O4@C powder has good dispersibility.

[0051] The obtained ultra-black light-absorbing coating was characterized by UV-Vis-NIR diffuse reflectance spectroscopy. The UV-Vis-NIR diffuse reflectance spectrum in the range of 200–2500 nm is as follows: Figure 4 As shown, by Figure 4 It can be seen that the solar absorptivity of the black coating with CuCr2O4@C pigment is 96.3% in the ultraviolet-visible-near infrared range, which proves that the CuCr2O4@C black coating has good light absorption properties.

[0052] The obtained coating was characterized by infrared absorptivity. The infrared emissivity of the CuCr2O4@C black coating was 94.3%, which proves that the CuCr2O4@C black coating has good emissivity. According to Kirchhoff's theorem, the absorptivity and emissivity are equal under thermal equilibrium. Therefore, this proves that the CuCr2O4@C black coating has good absorption performance in the infrared range.

[0053] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for preparing an ultra-black light-absorbing powder, characterized in that, include: (1) After mixing Cu(NO3)2 and Cr(NO3)3 in a certain proportion, deionized water is added to obtain a reaction solution. Then carbon black is added to the reaction solution and dispersed thoroughly to obtain a metal salt colloid. The molar and mass ratios of Cu(NO3)2, Cr(NO3)3, and carbon black in (1) are 26 mmol: 52 mmol: 1.776 g. (2) Add NaOH to the metal salt solution, stir evenly, centrifuge, wash and dry to obtain carbon black loaded metal particles, denoted as Cu(OH)2 / Cr(OH)3@C; (3) Place Cu(OH)2 / Cr(OH)3@C in a covered crucible and then calcine it in a muffle furnace to obtain carbon black loaded spinel oxide powder, which is the super black light-absorbing powder, denoted as CuCr2O4@C; The calcination temperature in (3) is 300℃; The obtained ultra-black light-absorbing powder was compounded with a water-based resin to prepare a coating with light-absorbing properties.

2. The method for preparing the ultra-black light-absorbing powder according to claim 1, characterized in that, (1) The molar ratio of Cu(NO3)2 and Cr(NO3)3 is 1:

2.

3. The method for preparing the ultra-black light-absorbing powder according to claim 1, characterized in that, (1) The amount of deionized water added is 200 mL.

4. The method for preparing the ultra-black light-absorbing powder according to claim 1, characterized in that, (2) The molar ratio of NaOH to Cr(NO3)3 added is 5:

1.

5. The method for preparing the ultra-black light-absorbing powder according to claim 1, characterized in that, (2) Add NaOH to the metal salt solution and stir for 30 minutes.

6. The method for preparing the ultra-black light-absorbing powder according to claim 1, characterized in that, (2) The drying temperature is 60℃.

7. The method for preparing the ultra-black light-absorbing powder according to claim 1, characterized in that, (3) The calcination time is 4h.

8. An ultra-black light-absorbing powder prepared by the method according to any one of claims 1 to 7.

9. An application of the ultra-black light-absorbing powder as described in claim 8, characterized in that, The ultra-black light-absorbing powder is compounded with water-based resin to prepare a coating with light-absorbing properties.

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