A high surface activity irregular micro-nano silver powder and its preparation method and application

Abstract

The present invention discloses a high-surface-activity irregular micro-nano silver powder and its preparation method and application. The preparation method comprises the following steps: S1. adding a dispersant solution to a silver nitrate solution to obtain a mixed solution; S2. simultaneously adding a complexing agent solution and a reducing agent solution to the mixed solution, heating and stirring the solution to react, and obtaining a reaction mixture; S3. removing impurities, crushing, and sieving the reaction mixture to obtain a high-surface-activity irregular micro-nano silver powder; the complexing agent comprises one or more of trisodium citrate, triethanolamine, hexadecyltrimethylammonium bromide, polyvinylpyrrolidone, and sodium dodecylsulfonate; the introduction of the complexing agent controls the release rate of silver ions during the entire redox reaction process, thereby regulating the size of the silver powder particles, increasing the specific surface area, and making the silver powder have a higher surface activity. The introduction of the dispersant improves the dispersibility of the silver powder, narrows the particle size distribution, and thereby increases the tap density of the silver powder.

Description

Technical Field

[0001] The present invention relates to the technical field of precious metal powder materials, and in particular to irregular micro-nano silver powder with high surface activity, and a preparation method and application thereof. Background Art

[0002] As industry competition becomes increasingly fierce, the requirements of various paste companies for functional silver powder are becoming increasingly stringent, and the printing line type of silver paste is becoming increasingly narrow. As a key material in the development and production of conductive silver paste for solar cells and electronic components, the properties of micro-nano silver powder directly affect the performance of silver paste in terms of printing, conductivity, weldability and weather resistance. Therefore, the demand for micro-nano silver powder with narrow particle size distribution, large specific surface area and high tap density is gradually increasing.

[0003] Micro-nano silver powder is generally prepared using a liquid phase reduction method. Patent CN 115609004 A discloses a method for preparing silver powder by reducing a silver ammonia solution with two reducing agents. A strong reducing agent is used to instantly generate silver nuclei after contact with the silver ammonia solution, and silver particles generated by a weak reducing agent grow on the silver nuclei, thereby achieving the separation of the nucleation and growth processes. The silver powder prepared by this method has a uniform particle size, high sphericity, and acceptable tap density, but a small specific surface area, low surface activity, and the reaction process is difficult to control. Patent CN 113290252 A discloses a method for preparing ultrafine silver powder, which first adds a polymer protective agent solution to a silver nitrate solution, then adds a strong alkali solution, and prepares the reduced silver powder by controlling the temperature of the reaction system. The resulting silver powder has a small particle size and a high specific surface area, but a low tap density.

[0004] Therefore, it is necessary to provide a micro-nano silver powder with narrow particle size distribution, large specific surface area and high tap density. Summary of the Invention

[0005] In view of this, the present application provides a high surface activity irregular micro-nano silver powder and its preparation method and application, to solve the problem of how to obtain a micro-nano silver powder with narrow particle size distribution, large specific surface area and high tap density.

[0006] In order to achieve the above technical objectives, this application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a method for preparing irregular micro-nano silver powder with high surface activity, comprising the following steps:

[0008] S1. The dispersant solution is added to the silver nitrate solution to obtain a mixed solution;

[0009] S2. The complexing agent solution and the reducing agent solution are simultaneously added to the mixed solution, heated and stirred to obtain a reaction mixture;

[0010] S3. The reaction mixture was removed from impurities, crushed, and sieved to obtain irregular micro-nano silver powder with high surface activity;

[0011] The compounding agent comprises one or more of trisodium citrate, triethanolamine, hexadecyltrimethylammonium bromide, polyvinyl pyrrolidone and sodium lauryl sulfonate.

[0012] Preferably, the dispersant includes one or more of carboxymethyl cellulose, gum arabic, gelatin, polyvinyl alcohol, polyacrylic acid, and polyethylene glycol.

[0013] Preferably, the reducing agent includes one or more of formaldehyde, formic acid, sodium sulfite, ascorbic acid, glucose, and hydrazine hydrate.

[0014] Preferably, in step S2, the temperature of heating and stirring is 25-75°C.

[0015] Preferably, the steps of step S3 are as follows: performing solid-liquid separation on the reaction mixture, washing the filter residue with deionized water until the conductivity is less than or equal to 15 μs / cm to obtain wet powder, drying the wet powder, crushing it, and passing it through a 200-mesh sieve to obtain irregular micro-nano silver powder with high surface activity.

[0016] Preferably, the mass ratio of the dispersant to silver nitrate is 0.001-0.015:1.

[0017] Preferably, the mass ratio of the complexing agent to silver nitrate is 0.03-0.3:1.

[0018] Preferably, the mass ratio of the reducing agent to the silver nitrate is 200-550:150-420.

[0019] In the second aspect, the present application provides a high surface activity irregular micro-nano silver powder, the parameters of which are: D 50 At 0.3-0.8 μm, D 90 At 0.9-1.5 μm, D 100 Less than 3μm, tap density greater than 4.2g / cm 3 , with a specific surface area of ​​1.1-1.6m 2 / g.

[0020] In a third aspect, the present application provides an application of irregular micro-nano silver powder with high surface activity in the optoelectronic field.

[0021] The beneficial effects of this application are as follows:

[0022] 1. The present invention controls the release rate of silver ions during the entire redox reaction process by introducing a complexing agent, thereby regulating the size of silver powder particles, increasing the specific surface area, and making it have higher surface activity.

[0023] 2. The present invention improves the dispersibility of silver powder and narrows the particle size distribution by introducing a dispersant, thereby increasing the tap density of the silver powder.

[0024] 3. The synthesis process of the present invention has the characteristics of rapid reaction, simple operation, stability and high efficiency. The silver powder obtained has a high yield and is easy to clean, and is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is an electron microscope photograph of the silver powder in Example 1;

[0026] Figure 2 This is an electron microscope photograph of the silver powder of Example 2;

[0027] Figure 3 This is an electron microscope photograph of the silver powder in Example 3. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] The present solution is further described below through specific implementation methods.

[0030] Example 1

[0031] Raw material preparation: Weigh 800 g of analytical grade silver nitrate and dissolve it in 5 L of deionized water to obtain a silver nitrate solution for later use; weigh 9 g of gum arabic and dissolve it in 300 mL of deionized water to obtain a dispersant solution for later use; weigh 40 g of triethanolamine and dissolve it in 2 L of deionized water to obtain a complexing agent solution for later use; weigh 450 g of ascorbic acid and dissolve it in 2 L of deionized water to obtain a reducing agent solution for later use.

[0032] A method for preparing irregular micro-nano silver powder with high surface activity comprises the following steps:

[0033] S1. The dispersant solution is added to the silver nitrate solution to obtain a mixed solution;

[0034] S2. Transfer the mixed solution to a reactor, start stirring, and heat to maintain the temperature at 30°C. While stirring at 450 rpm, pour the complexing agent solution and the reducing agent solution into the reactor simultaneously. After the addition is complete, continue stirring for 5 minutes until the reaction is complete to obtain a reaction mixture.

[0035] S3. After standing for 20 minutes, discharge the material into a solid-liquid separator, filter, and wash with deionized water until the conductivity is below 15 μs / cm. Place the wet powder in a forced air drying oven and dry it at 60°C for 12 hours. The dried silver powder is crushed and sieved to 200 mesh to obtain irregular micro-nano silver powder with high surface activity.

[0036] The yield of the high surface activity irregular micro-nano silver powder in this embodiment is 99.89%. The electron microscope photo of the prepared silver powder is as follows: Figure 1 shown.

[0037] Example 2

[0038] Raw material preparation: Weigh 500 g of analytical grade silver nitrate and dissolve it in 2 L of deionized water to obtain a silver nitrate solution for later use; weigh 4 g of gelatin and dissolve it in 100 mL of deionized water to obtain a dispersant solution for later use; weigh 22 g of hexadecyltrimethylammonium bromide and dissolve it in 300 mL of deionized water to obtain a complexing agent solution for later use; weigh 80 g of hydrazine hydrate and dissolve it in 300 mL of deionized water to obtain a reducing agent solution for later use.

[0039] A method for preparing irregular micro-nano silver powder with high surface activity comprises the following steps:

[0040] S1. The dispersant solution is added to the silver nitrate solution to obtain a mixed solution;

[0041] S2. Transfer the mixed solution to a reactor, start stirring, and heat to maintain the temperature at 50°C. While stirring at 400 rpm, pour the complexing agent solution and the reducing agent solution into the reactor simultaneously. After the addition is complete, continue stirring for 10 minutes until the reaction is complete, to obtain a reaction mixture.

[0042] S3. After standing for 20 minutes, discharge the material into a solid-liquid separator, filter, and wash with deionized water until the conductivity is below 15 μs / cm. Place the wet powder in a forced air drying oven and dry it at 70°C for 12 hours. The dried silver powder is crushed and sieved to 200 mesh to obtain irregular micro-nano silver powder with high surface activity.

[0043] The yield of the irregular micro-nano silver powder with high surface activity in this embodiment is 99.93%. The electron microscope photo of the prepared silver powder is shown in FIG. Figure 2 shown.

[0044] Example 3

[0045] Raw material preparation: Weigh 500 g of analytical grade silver nitrate and dissolve it in 1.25 L of deionized water to obtain a silver nitrate solution for later use; weigh 1.5 g of polyacrylic acid and dissolve it in 100 mL of deionized water to obtain a dispersant solution for later use; weigh 90 g of trisodium citrate and dissolve it in 1 L of deionized water to obtain a complexing agent solution for later use; weigh 420 g of glucose and dissolve it in 1 L of deionized water to obtain a reducing agent solution for later use.

[0046] A method for preparing irregular micro-nano silver powder with high surface activity comprises the following steps:

[0047] S1. The dispersant solution is added to the silver nitrate solution to obtain a mixed solution;

[0048] S2. Transfer the mixed solution to a reactor, start stirring, and heat to maintain the temperature at 70°C. While stirring at 350 rpm, pour the complexing agent solution and the reducing agent solution into the reactor simultaneously. After the addition is complete, continue stirring for 10 minutes until the reaction is complete to obtain a reaction mixture.

[0049] S3. After standing for 10 minutes, discharge the material into a solid-liquid separator, filter, and wash with deionized water until the conductivity is below 15 μs / cm. Place the wet powder in a forced air drying oven and dry it at 60°C for 16 hours. The dried silver powder is crushed and sieved to 200 mesh to obtain irregular micro-nano silver powder with high surface activity.

[0050] The yield of the high surface activity irregular micro-nano silver powder in this embodiment is 99.97%. The electron microscope photo of the prepared silver powder is as follows: Figure 3 shown.

[0051] Comparative Example 1

[0052] A method for preparing micro-nano silver powder is the same as that of Example 1 except that no complexing agent is added.

[0053] Comparative Example 2

[0054] A method for preparing micro-nano silver powder is the same as that of Example 1 except that no dispersant is added.

[0055] Table 1 Particle size, tap density and specific surface area of ​​the silver powder obtained in the specific embodiment

[0056]

[0057] It can be seen that the high-surface-activity irregular micro-nano silver powder obtained in the present application has a narrow particle size distribution, a large specific surface area and a high tap density, which is beneficial to the improvement of its sintering activity and aging resistance. The present application adopts a liquid-phase reduction method, and all materials are poured in at one time, so the reaction can reach the end point quickly. The prepared silver powder is easy to wash and has a high yield.

[0058] The above are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing irregular micro-nano silver powder with high surface activity, characterized in that: The following steps are involved: S1. The dispersant solution is added to the silver nitrate solution to obtain a mixed solution; S2. The complexing agent solution and the reducing agent solution are simultaneously added to the mixed solution, heated and stirred to obtain a reaction mixture; S3. The reaction mixture is removed from impurities, crushed, and sieved to obtain the highly surface active irregular micro-nano silver powder; The compounding agent includes one or more of trisodium citrate, triethanolamine, cetyltrimethylammonium bromide, polyvinyl pyrrolidone, and sodium dodecyl sulfate; the dispersant includes one or more of carboxymethyl cellulose, gum arabic, gelatin, polyvinyl alcohol, polyacrylic acid, and polyethylene glycol; the reducing agent includes one or more of formaldehyde, formic acid, sodium sulfite, ascorbic acid, glucose, and hydrazine hydrate; in step S2, the heating and stirring temperature is 25-75°C; the mass ratio of the dispersant to the silver nitrate is 0.001-0.015:1; the mass ratio of the compounding agent to the silver nitrate is 0.03-0.3:1; the mass ratio of the reducing agent to the silver nitrate is 200-550:150-420; the parameters of the high surface activity irregular micro-nano silver powder are: D50 is 0.3-0.8μm, D90 is 0.9-1.5μm, D100 is less than 3μm, and the tap density is greater than 4.2g / cm 3 , with a specific surface area of ​​1.1-1.6m 2 / g.

2. The method for preparing irregular micro-nano silver powder with high surface activity according to claim 1, characterized in that: The steps of step S3 are as follows: performing solid-liquid separation on the reaction mixture, washing the filter residue with deionized water until the conductivity is less than or equal to 15 μs / cm to obtain a wet powder, and drying, crushing, and passing the wet powder through a 200-mesh sieve to obtain the high-surface-activity irregular micro-nano silver powder.

Images