A flaky silver-coated aluminum powder pigment, a preparation method and application thereof
By constructing an aminated silica layer and grafting sodium dithiocarbamate on the surface of flake aluminum powder, the directional deposition of silver ions is promoted to form a dense silver shell layer. This solves the problems of the complexity of silver-coated aluminum powder pigment preparation and insufficient silver layer density, achieving high metallic luster, good conductivity and electromagnetic shielding effect, and is suitable for coatings and inks.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEFEI SUNRISE PIGMENTS
- Filing Date
- 2026-02-02
- Publication Date
- 2026-06-16
AI Technical Summary
In the existing technology, the preparation process of silver-coated aluminum powder is complicated, the density of the silver layer is insufficient, resulting in an excessively thick silver coating layer on the surface of the aluminum powder, excessively large particle size, and high silver content. Furthermore, silver-coated glass pigments lack metallic effect and hiding power, making them difficult to apply in coatings and inks.
By constructing an aminated silica layer on the surface of flake aluminum powder and grafting sodium dithiocarbamate, silver ions are promoted to be deposited in a directional manner on the silica layer surface, forming a dense silver shell layer with strong adhesion, thus solving the problem of uniform silver coating.
This invention achieves a strong metallic luster, good conductivity, high storage stability, and significantly improved electromagnetic shielding effect in flake-shaped silver-coated aluminum powder pigments, making them suitable for coatings and inks.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of pigment technology, and in particular to a flake-shaped silver-coated aluminum powder pigment, its preparation method, and its application. Background Technology
[0002] Currently, most silver-coated aluminum powders on the market use traditional chemical silver plating methods. This method has a complex preparation process, requiring roughening, sensitization, and activation steps, making the preparation process quite complicated. Furthermore, it cannot effectively control the rate of silver grain formation and nucleation, resulting in an excessively thick silver coating on the aluminum surface, with excessively large particle sizes and high silver content. Similar pigments, such as silver-coated glass, do not have the strong metallic effect of silver-coated aluminum, and their hiding power is also much weaker. These problems pose a significant challenge to the application of silver-coated composite powders in coatings, inks, and other fields.
[0003] Patent CN119681263A discloses a core-shell structured sheet-like silver-coated aluminum powder, its preparation method, and its applications. It utilizes dopamine hydrochloride as a raw material, reacting weakly reducing polydopamine with silver nitrate to achieve activation. The dopamine molecule contains active functional groups such as amino and hydroxyl groups, which can self-polymerize under alkaline conditions to form polydopamine. These active functional groups in polydopamine coordinate with silver ions, thus playing a role in connecting and fixing silver ions during silver deposition, promoting uniform silver coating on the aluminum powder surface and forming a strong bonding force. However, the coordination effect of polydopamine on silver ions is weak, resulting in insufficient density of the silver layer and failing to effectively improve the stability and corrosion resistance of the sheet-like silver-coated aluminum powder. Summary of the Invention
[0004] Based on the technical problems existing in the background art, the present invention proposes a flake-shaped silver-coated aluminum powder pigment, its preparation method and application. By effectively controlling the directional deposition process of silver nanoparticles, the silver layer is completely coated, with strong density and strong bonding force with the core aluminum particles. It can be used efficiently in coatings and inks, and while having a strong metallic luster, it also obtains excellent electromagnetic shielding performance.
[0005] The present invention provides a method for preparing flake-shaped silver-coated aluminum powder pigment, comprising the following steps:
[0006] S1. Coating the surface of flake aluminum powder with aminated silica to obtain aminated silica-coated flake aluminum powder;
[0007] S2. Aminated silica is coated with sodium dithiocarbamate to obtain flake aluminum powder with coordinating groups on the surface.
[0008] S3. Coat the surface of the flake aluminum powder with coordinating groups with silver to obtain the flake silver-coated aluminum powder pigment.
[0009] In this invention, flake aluminum powder is selected. By constructing a dense layer of aminated silica (SiO2) on the surface of the flake aluminum powder, the reactive aluminum core is completely isolated from the external environment, solving the oxidation problem of high specific surface area aluminum powder during processing, storage, and use. At the same time, sodium dithiocarbamate with strong adsorption and coordination properties is grafted onto the surface of the flake aluminum powder coated with aminated silica. It can subsequently coordinate and chelate with silver ions, promoting the directional deposition and reduction of silver ions on the surface of the silica layer, forming a silver shell layer with excellent binding force and density. Ultimately, the resulting flake silver-coated aluminum powder pigment coating is dense and uniform, with strong metallic luster, and significantly improved anti-oxidation performance and electromagnetic shielding effect.
[0010] Preferably, in step S1, coating the surface of the flake aluminum powder with aminated silica specifically includes: dispersing the flake aluminum powder in an alcohol solvent, adding tetraethyl orthosilicate, an aminosilane coupling agent and an alkaline regulator to carry out a hydrolysis reaction, thereby obtaining the aminated silica-coated flake aluminum powder.
[0011] Preferably, the aminosilane coupling agent is at least one of 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane; the alkalinity regulator is at least one of ammonia, sodium bicarbonate or ethylenediamine; and the alcohol solvent is at least one of ethanol, n-propanol, isopropanol or n-butanol.
[0012] Preferably, the amount of tetraethyl orthosilicate used is 10-25 wt% of the flake aluminum powder, and the amount of aminosilane coupling agent used is 3-12 wt% of the flake aluminum powder.
[0013] The hydrolysis reaction is carried out at a temperature of 50-70℃ for 4-6 hours.
[0014] Preferably, in step S2, grafting sodium dithiocarbamate onto the surface of aminated silica-coated flake aluminum powder specifically includes: adding aminated silica-coated flake aluminum powder to an aqueous sodium hydroxide solution, and then adding carbon disulfide to react, thereby obtaining the flake aluminum powder with coordinating groups on the surface.
[0015] Preferably, the amount of sodium hydroxide used is 1-5 wt% of the aminated silica-coated flake aluminum powder, and the amount of carbon disulfide used is 1-10 wt% of the aminated silica-coated flake aluminum powder.
[0016] Preferably, in step S3, coating the surface of the flake aluminum powder with coordinating groups with silver specifically includes: adding the flake aluminum powder with coordinating groups to a reducing agent solution and a silver complexing solution to carry out a reduction reaction, thereby obtaining the flake silver-coated aluminum powder pigment.
[0017] Preferably, the reducing agent is at least one of glucose, fructose, ascorbic acid, sodium borohydride, or potassium sodium tartrate, and the silver complexing solution comprises a silver salt and a complexing agent, wherein the silver salt is silver nitrate, and the complexing agent is at least one of triethylamine, triethanolamine, diethylenetriamine, ethylenediamine, sodium citrate tetraacetate, or ammonia.
[0018] The present invention also proposes a flake-shaped silver-coated aluminum powder pigment, which is prepared by the above preparation method.
[0019] This invention also proposes an application of the above-mentioned flake-shaped silver-coated aluminum powder pigment in coatings and inks.
[0020] The beneficial effects of the flake-shaped silver-coated aluminum powder described in this invention are as follows:
[0021] (1) High metallic luster: Compared with the traditional process, the obtained flake silver-coated aluminum powder pigment has a stronger metallic texture and shines brighter under light conditions; (2) Good conductivity: The flake form forms a highly efficient conductive network in the substrate; the silver plating layer is dense, has high conductivity, and has a good shielding effect; (3) High storage stability: The silver coating layer is dense and has good thermal storage stability, which can ensure that the basic performance remains unchanged after 180 days of storage at 50℃. Attached Figure Description
[0022] Figure 1 This is a photograph of the flake-shaped silver-coated aluminum powder pigment described in Embodiment 1 of the present invention;
[0023] Figure 2 This is a cross-sectional electron microscope image of the flake-shaped silver-coated aluminum powder pigment described in Embodiment 1 of the present invention;
[0024] Figure 3 This is a schematic diagram of the structure of the sheet-like aluminum powder with coordinating groups on the surface described in Embodiment 1 of the present invention;
[0025] Figure 4 The infrared spectrum of the sheet-like aluminum powder with coordinating groups on its surface as described in Embodiment 1 of the present invention. Detailed Implementation
[0026] The technical solution of the present invention will be described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.
[0027] Example 1
[0028] A flake-shaped silver-coated aluminum powder pigment is prepared by the following method:
[0029] (1) Add oily flake aluminum pigment (solid content of 55wt%, D50 particle size of 25μm, average aspect ratio of 100) to anhydrous ethanol and stir thoroughly for 3h. The amount of anhydrous ethanol is 10 times that of oily flake aluminum pigment. Filter, wash with anhydrous ethanol, and vacuum dry to obtain de-oiled flake aluminum powder.
[0030] (2) Tetraethyl orthosilicate and silane coupling agent KH-550 were added to anhydrous ethanol and mixed evenly to obtain solution A; ammonia water (concentration of 26wt%) and deionized water were added to anhydrous ethanol and mixed evenly to obtain solution B; the degreased flake aluminum powder was added to anhydrous ethanol and stirred and dispersed evenly. After heating to 60℃, solutions A and B were added at the same time. The amount of tetraethyl orthosilicate was 15wt% of the flake aluminum powder, the amount of silane coupling agent KH-550 was 8wt% of the flake aluminum powder, the amount of ammonia water was 60wt% of the flake aluminum powder, and the amount of deionized water was 1 times that of the flake aluminum powder. The mixture was kept at the temperature and stirred for 5h. After standing and aging for 8h, it was filtered, washed with anhydrous ethanol, and dried to obtain aminated silica-coated flake aluminum powder.
[0031] (3) Aminated silica-coated flake aluminum powder was added to a sodium hydroxide aqueous solution (concentration of 1 mol / L) and stirred thoroughly to disperse evenly. Then carbon disulfide was added, wherein the amount of sodium hydroxide was 3 wt% of the aminated silica-coated flake aluminum powder and the amount of carbon disulfide was 6 wt% of the aminated silica-coated flake aluminum powder. The mixture was stirred at room temperature for 3 h, filtered, washed with anhydrous ethanol, and dried to obtain flake aluminum powder with coordinating groups on the surface. Its structural schematic diagram and infrared spectrum are shown below. Figure 3 , 4 As shown;
[0032] (4) Add silver nitrate to deionized water, and slowly add ammonia water under stirring until the brown precipitate is completely dissolved to obtain a silver ammonia solution; add glucose and potassium sodium tartrate to deionized water to obtain a reducing agent solution; add flake aluminum powder with coordinating groups on the surface to deionized water and stir thoroughly to disperse evenly. After heating to 30°C, add silver ammonia solution and reducing agent solution dropwise under vigorous stirring. The amount of silver nitrate is 30 wt% of the flake aluminum powder with coordinating groups on the surface, the amount of glucose is 1 times that of the flake aluminum powder with coordinating groups on the surface, and the amount of potassium sodium tartrate is 60 wt% of the flake aluminum powder with coordinating groups on the surface. After the addition is complete, keep the reaction at the temperature for 1 hour, let it stand and cool, filter, wash with deionized water and ethanol, and vacuum dry to obtain the flake silver-coated aluminum powder pigment. Its physical picture and cross-sectional electron microscope image are shown below. Figure 1 , 2 As shown.
[0033] Example 2
[0034] A flake-shaped silver-coated aluminum powder pigment is prepared by the following method:
[0035] (1) Add oily flake aluminum pigment (solid content of 55wt%, D50 particle size of 25μm, average aspect ratio of 100) to anhydrous ethanol and stir thoroughly for 3h. The amount of anhydrous ethanol is 10 times that of oily flake aluminum pigment. Filter, wash with anhydrous ethanol, and vacuum dry to obtain de-oiled flake aluminum powder.
[0036] (2) Tetraethyl orthosilicate and silane coupling agent KH-540 were added to anhydrous ethanol and mixed evenly to obtain solution A; ammonia water (concentration of 26wt%) and deionized water were added to anhydrous ethanol and mixed evenly to obtain solution B; the degreased flake aluminum powder was added to anhydrous ethanol and stirred and dispersed evenly. After heating to 50℃, solutions A and B were added at the same time. The amount of tetraethyl orthosilicate was 10wt% of the flake aluminum powder, the amount of silane coupling agent KH-540 was 5wt% of the flake aluminum powder, the amount of ammonia water was 40wt% of the flake aluminum powder, and the amount of deionized water was 1 times that of the flake aluminum powder. The mixture was kept at the temperature and stirred for 6h. After standing and aging for 8h, it was filtered, washed with anhydrous ethanol, and dried to obtain aminated silica-coated flake aluminum powder.
[0037] (3) Add aminated silica-coated flake aluminum powder to sodium hydroxide aqueous solution (concentration is 1 mol / L) and stir thoroughly to disperse evenly. Then add carbon disulfide. The amount of sodium hydroxide is 2 wt% of the aminated silica-coated flake aluminum powder and the amount of carbon disulfide is 4 wt% of the aminated silica-coated flake aluminum powder. Stir the reaction at room temperature for 3 h, filter, wash with anhydrous ethanol, and dry to obtain flake aluminum powder with coordinating groups on the surface.
[0038] (4) Add silver nitrate to deionized water and slowly add ammonia water under stirring until the brown precipitate is completely dissolved to obtain silver ammonia solution; add glucose to deionized water to obtain reducing agent solution; add flake aluminum powder with coordinating groups on the surface to deionized water and stir to disperse evenly. After heating to 30°C, add silver ammonia solution and reducing agent solution dropwise under vigorous stirring. The amount of silver nitrate is 20 wt% of the flake aluminum powder with coordinating groups on the surface, and the amount of glucose is 1.5 times that of the flake aluminum powder with coordinating groups on the surface. After the addition is complete, keep the reaction at the temperature for 1 hour, let it stand and cool, filter, wash with deionized water and ethanol, and dry under vacuum to obtain the flake silver-coated aluminum powder pigment.
[0039] Example 3
[0040] A flake-shaped silver-coated aluminum powder pigment is prepared by the following method:
[0041] (1) Add oily flake aluminum pigment (solid content of 55wt%, D50 particle size of 25μm, average aspect ratio of 100) to anhydrous ethanol and stir thoroughly for 3h. The amount of anhydrous ethanol is 10 times that of oily flake aluminum pigment. Filter, wash with anhydrous ethanol, and vacuum dry to obtain de-oiled flake aluminum powder.
[0042] (2) Tetraethyl orthosilicate and silane coupling agent KH-550 were added to anhydrous ethanol and mixed evenly to obtain solution A; ammonia water (concentration of 26wt%) and deionized water were added to anhydrous ethanol and mixed evenly to obtain solution B; the degreased flake aluminum powder was added to anhydrous ethanol and stirred and dispersed evenly. After heating to 70℃, solutions A and B were added at the same time. The amount of tetraethyl orthosilicate was 25wt% of the flake aluminum powder, the amount of silane coupling agent KH-550 was 12wt% of the flake aluminum powder, the amount of ammonia water was 60wt% of the flake aluminum powder, and the amount of deionized water was 1.5 times that of the flake aluminum powder. The mixture was kept at the temperature and stirred for 4h. After standing and aging for 8h, it was filtered, washed with anhydrous ethanol, and dried to obtain aminated silica-coated flake aluminum powder.
[0043] (3) Add aminated silica-coated flake aluminum powder to sodium hydroxide aqueous solution (concentration is 1 mol / L) and stir thoroughly to disperse evenly. Then add carbon disulfide. The amount of sodium hydroxide is 5 wt% of the aminated silica-coated flake aluminum powder and the amount of carbon disulfide is 10 wt% of the aminated silica-coated flake aluminum powder. Stir the reaction at room temperature for 3 h, filter, wash with anhydrous ethanol, and dry to obtain flake aluminum powder with coordinating groups on the surface.
[0044] (4) Add silver nitrate to deionized water and slowly add ammonia water under stirring until the brown precipitate is completely dissolved to obtain silver ammonia solution; add glucose and potassium sodium tartrate to deionized water to obtain reducing agent solution; add flake aluminum powder with coordinating groups on the surface to deionized water and stir to disperse evenly. After heating to 30°C, add silver ammonia solution and reducing agent solution dropwise under vigorous stirring. The amount of silver nitrate is 40 wt% of the flake aluminum powder with coordinating groups on the surface, the amount of glucose is twice the amount of the flake aluminum powder with coordinating groups on the surface, and the amount of potassium sodium tartrate is once the amount of the flake aluminum powder with coordinating groups on the surface. After the addition is complete, keep the reaction at the temperature for 1 hour, let it stand and cool, filter, wash with deionized water and ethanol, and dry under vacuum to obtain the flake silver-coated aluminum powder pigment.
[0045] Comparative Example 1
[0046] A flake-shaped silver-coated aluminum powder pigment is prepared by the following method:
[0047] (1) Add oily flake aluminum pigment (solid content of 55wt%, D50 particle size of 25μm, average aspect ratio of 100) to anhydrous ethanol and stir thoroughly for 3h. The amount of anhydrous ethanol is 10 times that of oily flake aluminum pigment. Filter, wash with anhydrous ethanol, and vacuum dry to obtain de-oiled flake aluminum powder.
[0048] (2) Tetraethyl orthosilicate and silane coupling agent KH-550 were added to anhydrous ethanol and mixed evenly to obtain solution A; ammonia water (concentration of 26wt%) and deionized water were added to anhydrous ethanol and mixed evenly to obtain solution B; the degreased flake aluminum powder was added to anhydrous ethanol and stirred and dispersed evenly. After heating to 60℃, solutions A and B were added at the same time. The amount of tetraethyl orthosilicate was 15wt% of the flake aluminum powder, the amount of silane coupling agent KH-550 was 8wt% of the flake aluminum powder, the amount of ammonia water was 60wt% of the flake aluminum powder, and the amount of deionized water was 1 times that of the flake aluminum powder. The mixture was kept at the temperature and stirred for 5h. After standing and aging for 8h, it was filtered, washed with anhydrous ethanol, and dried to obtain aminated silica-coated flake aluminum powder.
[0049] (3) Add silver nitrate to deionized water and slowly add ammonia water under stirring until the brown precipitate is completely dissolved to obtain silver ammonia solution; add glucose and potassium sodium tartrate to deionized water to obtain reducing agent solution; add aminated silica-coated flake aluminum powder to deionized water and stir thoroughly to disperse evenly. After heating to 30°C, add silver ammonia solution and reducing agent solution dropwise under vigorous stirring. The amount of silver nitrate is 30 wt% of the aminated silica-coated flake aluminum powder, the amount of glucose is 1 times that of the aminated silica-coated flake aluminum powder, and the amount of potassium sodium tartrate is 60 wt% of the aminated silica-coated flake aluminum powder. After the addition is complete, keep the reaction at the temperature for 1 hour, let it stand and cool, filter, wash with deionized water and ethanol, and vacuum dry to obtain the flake silver-coated aluminum powder pigment.
[0050] Comparative Example 2
[0051] A flake-shaped silver-coated aluminum powder pigment is prepared by the following method:
[0052] (1) Add oily flake aluminum pigment (solid content of 55wt%, D50 particle size of 25μm, average aspect ratio of 100) to anhydrous ethanol and stir thoroughly for 3h. The amount of anhydrous ethanol is 10 times that of oily flake aluminum pigment. Filter, wash with anhydrous ethanol, and vacuum dry to obtain de-oiled flake aluminum powder.
[0053] (2) Tetraethyl orthosilicate and silane coupling agent KH-550 were added to anhydrous ethanol and mixed evenly to obtain solution A; ammonia water (concentration of 26wt%) and deionized water were added to anhydrous ethanol and mixed evenly to obtain solution B; the degreased flake aluminum powder was added to anhydrous ethanol and stirred and dispersed evenly. After heating to 60℃, solutions A and B were added at the same time. The amount of tetraethyl orthosilicate was 15wt% of the flake aluminum powder, the amount of silane coupling agent KH-550 was 8wt% of the flake aluminum powder, the amount of ammonia water was 60wt% of the flake aluminum powder, and the amount of deionized water was 1 times that of the flake aluminum powder. The mixture was kept at the temperature and stirred for 5h. After standing and aging for 8h, it was filtered, washed with anhydrous ethanol, and dried to obtain aminated silica-coated flake aluminum powder.
[0054] (3) Add dopamine hydrochloride to tris(hydroxymethyl)aminomethane buffer (concentration of 0.1 mol / L) and stir to dissolve to obtain dopamine solution (pH=8.5); add aminated silica-coated flake aluminum powder to dopamine solution and stir to disperse evenly. The amount of dopamine hydrochloride is 20 wt% of the aminated silica-coated flake aluminum powder. Stir and react at room temperature for 24 h, filter, wash with deionized water, and dry to obtain flake aluminum powder with polydopamine on the surface.
[0055] (4) Add silver nitrate to deionized water and slowly add ammonia water under stirring until the brown precipitate is completely dissolved to obtain silver ammonia solution; add glucose and potassium sodium tartrate to deionized water to obtain reducing agent solution; add aluminum flakes with polydopamine on the surface to deionized water and stir to disperse evenly. After heating to 30°C, add silver ammonia solution and reducing agent solution dropwise under vigorous stirring. The amount of silver nitrate is 30 wt% of the aluminum flakes with polydopamine on the surface, the amount of glucose is 1 times that of the aluminum flakes with polydopamine on the surface, and the amount of potassium sodium tartrate is 60 wt% of the aluminum flakes with polydopamine on the surface. After the addition is complete, keep the reaction at the temperature for 1 hour, let it stand and cool, filter, wash with deionized water and ethanol, and vacuum dry to obtain the flake silver-coated aluminum powder pigment.
[0056] Performance testing:
[0057] The flake-shaped silver-coated aluminum powder pigment described in the above embodiments and comparative examples is used as a pigment in a coating, which is prepared by the following method:
[0058] Methyl methacrylate, butyl acrylate, and 2-hydroxyethyl methacrylate were added to anhydrous ethanol in a mass ratio of 2:1:1. The mixture was stirred and mixed thoroughly under nitrogen protection. Then, 2 wt% of azobisisobutyronitrile (AIBN) was added, and the mixture was stirred at 70°C for 4 hours. After distilling to remove the solvent, an acrylic resin was obtained. The acrylic resin was added to a mixed solvent of water and anhydrous ethanol (volume ratio 3:1) and stirred thoroughly to disperse evenly, resulting in an aqueous acrylic resin emulsion with a solid content of 30 wt%. The flake-shaped silver-coated aluminum powder pigment was added to the aqueous acrylic resin emulsion at a concentration of 5 wt% of the emulsion. After thorough dispersion, a coating was obtained. The coating was poured into a spray gun and evenly sprayed onto the surface of a plastic substrate. The substrate was then dried in a 120°C forced-air drying oven to obtain the test sample. The test results are shown in Table 1.
[0059] A vector network analyzer connected to two X-band waveguides was used to test the electromagnetic shielding performance of the coating of the test samples using the waveguide method at room temperature, in the X-band (8.2-18.0 GHz) and with a bandwidth of 1 kHz. The corrosion resistance of the test samples was tested according to the ASTM D2247 damp heat cycling test (test temperature: 85℃ ± 2℃, test humidity: 85% RH ± 5%; test duration: 500h; color difference change less than 1 as measured by a colorimeter and gloss loss rate less than 5% as measured by a gloss meter are considered excellent, the rest are considered average). The 60° gloss was tested according to GB / T9574-2017.
[0060] Table 1 Performance Test Results
[0061]
[0062] As can be seen from Table 1, the brightness, corrosion resistance, and electromagnetic shielding performance of the flake-shaped silver-coated aluminum powder pigment described in the embodiments are significantly improved.
[0063] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing flake-shaped silver-coated aluminum powder pigment, characterized in that, Includes the following steps: S1. Coating the surface of flake aluminum powder with aminated silica to obtain aminated silica-coated flake aluminum powder; S2. Aminated silica is coated with sodium dithiocarbamate to obtain flake aluminum powder with coordinating groups on the surface. S3. Coat the surface of the flake aluminum powder with coordinating groups with silver to obtain the flake silver-coated aluminum powder pigment. In step S1, coating the surface of the flake aluminum powder with aminated silica specifically includes: dispersing the flake aluminum powder in an alcohol solvent, adding tetraethyl orthosilicate, an aminosilane coupling agent and an alkaline regulator to carry out a hydrolysis reaction, thereby obtaining the aminated silica-coated flake aluminum powder. In step S2, grafting sodium dithiocarbamate onto the surface of aminated silica-coated flake aluminum powder specifically includes: adding aminated silica-coated flake aluminum powder to an aqueous sodium hydroxide solution, and then adding carbon disulfide to react, thereby obtaining the flake aluminum powder with coordinating groups on the surface.
2. The method for preparing flake-shaped silver-coated aluminum powder pigment according to claim 1, characterized in that, The aminosilane coupling agent is at least one of 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane; the alkalinity regulator is at least one of ammonia, sodium bicarbonate or ethylenediamine; and the alcohol solvent is at least one of ethanol, n-propanol, isopropanol or n-butanol.
3. The method for preparing flake-shaped silver-coated aluminum powder pigment according to claim 1 or 2, characterized in that, The amount of the tetraethyl orthosilicate is 10-25 wt% of the flake aluminum powder, and the amount of the aminosilane coupling agent is 3-12 wt% of the flake aluminum powder. The hydrolysis reaction is carried out at a temperature of 50-70℃ for 4-6 hours.
4. The method for preparing flake-shaped silver-coated aluminum powder pigment according to claim 1, characterized in that, The amount of sodium hydroxide used is 1-5 wt% of the aminated silica-coated flake aluminum powder, and the amount of carbon disulfide used is 1-10 wt% of the aminated silica-coated flake aluminum powder.
5. The method for preparing flake-shaped silver-coated aluminum powder pigment according to claim 1 or 2, characterized in that, In step S3, the process of coating the surface of the flake aluminum powder with coordinating groups with silver specifically includes: adding the flake aluminum powder with coordinating groups to a reducing agent solution and a silver complexing solution to carry out a reduction reaction, thereby obtaining the flake silver-coated aluminum powder pigment.
6. The method for preparing the flake-shaped silver-coated aluminum powder pigment according to claim 5, characterized in that, The reducing agent is at least one of glucose, fructose, ascorbic acid, sodium borohydride, or potassium sodium tartrate. The silver complexing solution includes a silver salt and a complexing agent. The silver salt is silver nitrate, and the complexing agent is at least one of triethylamine, triethanolamine, diethylenetriamine, ethylenediamine, sodium citrate tetraacetate, or ammonia.
7. A flake-shaped silver-coated aluminum powder pigment, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.
8. The application of the flake-shaped silver-coated aluminum powder pigment of claim 7 in coatings and inks.