Flower-shaped spherical silver powder and its preparation method

Abstract

This application relates to a flower-shaped spherical silver powder and a preparation method thereof. The preparation method includes: preparing a first solution and a second solution, where the first solution includes silver nitrate and the second solution includes a reducing agent, a dispersant, and a surfactant; after adjusting the pH value of the second solution to a preset value, adding it to the first solution for reaction to obtain a silver powder suspension, and the preset value is 3 to 7; separating the flower-shaped spherical silver powder from the silver powder suspension, and the flower-shaped spherical silver powder is a spherical silver powder with a flower-shaped structure. By introducing a surfactant, this application can effectively control the growth mode of the silver powder, making its surface rough, so that flower-shaped spherical silver powder with a large specific surface area can be prepared. Moreover, the preparation process is simple and has good application prospects in many fields such as conductive pastes and conductive coatings.

Description

Technical Field

[0001] The present application relates to the technical field of metal powder preparation, and particularly relates to a flower-shaped spherical silver powder and a preparation method thereof. Background Art

[0002] In the technical field of metal powder preparation, silver powder occupies a core position in many high-tech applications such as electronic packaging, conductive coatings, and antibacterial materials due to its excellent electrical conductivity and chemical stability. The properties and applications of silver powder depend on the size and morphology of silver particles.

[0003] However, due to the agglomeration and bridging phenomena of nano metal particles, their specific surface area is limited. Therefore, how to prepare silver particles with a high specific surface area is a problem that needs to be solved currently and in the future. Summary of the Invention

[0004] The purpose of the present application is to provide a flower-shaped spherical silver powder and a preparation method thereof, so as to prepare a flower-shaped spherical silver powder with a large specific surface area, thereby having good application prospects in many fields such as conductive pastes and conductive coatings.

[0005] The embodiment of the present application provides a preparation method of a flower-shaped spherical silver powder. The preparation method of the flower-shaped spherical silver powder includes: preparing a first solution and a second solution, the first solution includes silver nitrate, and the second solution includes a reducing agent, a dispersant, and a surfactant; after adjusting the pH value of the second solution to a preset value, adding it to the first solution for reaction to obtain a silver powder suspension, and the preset value is 3-7; separating the flower-shaped spherical silver powder from the silver powder suspension, and the flower-shaped spherical silver powder is a spherical silver powder with a flower-shaped structure.

[0006] Wherein, the mass concentration of silver nitrate in the first solution is 5-25%, and the mass concentration of the reducing agent in the second solution is 10-20%; the mass ratio of the reducing agent in the second solution to the silver nitrate in the first solution is 50-60%; the mass ratio of the dispersant in the second solution to the silver nitrate in the first solution is 5-20%; the mass ratio of the surfactant in the second solution to the silver nitrate in the first solution is 0.5-5%.

[0007] Wherein, the reducing agent includes at least one of glucose, ascorbic acid, hydrazine hydrate, hydrogen peroxide, formaldehyde, and acetaldehyde; the dispersant includes at least one of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, arabic gum, gelatin, and tween; the surfactant includes at least one of silane coupling agent, span, oleic acid, sodium dodecylbenzenesulfonate, methylbenzotriazole, and benzotriazole.

[0008] Wherein, the surfactant is sodium dodecylbenzenesulfonate or benzotriazole.

[0009] Among them, after adjusting the pH value of the second solution to a preset value, it is added to the first solution for reaction to obtain a silver powder suspension, including: after adjusting the pH value of the second solution to a preset value by adding a pH regulator to the second solution, it is added to the first solution for reaction to obtain a silver powder suspension; the pH regulator includes at least one of ammonia water, sodium hydroxide, sodium bicarbonate, oxalic acid, phosphoric acid, nitric acid, hydrochloric acid, and sulfuric acid.

[0010] Among them, after adjusting the pH value of the second solution to a preset value, it is added to the first solution for reaction to obtain a silver powder suspension, including: after adjusting the pH value of the second solution to a preset value, it is added to the first solution for reaction under stirring conditions within a preset addition time to obtain a silver powder suspension, and the preset addition time is 5 - 15 min.

[0011] Among them, after adjusting the pH value of the second solution to a preset value, it is added to the first solution for reaction to obtain a silver powder suspension, including: after adjusting the pH value of the second solution to a preset value, it is added to the first solution for reaction under a preset reaction temperature condition to obtain a silver powder suspension, and the preset reaction temperature is 25 - 45 °C.

[0012] Among them, separating the flower-shaped spherical silver powder from the silver powder suspension includes: performing solid-liquid separation on the silver powder suspension, washing the separated solid, and drying the washed solid, the drying temperature is 40 - 60 °C, and the drying time is 60 - 120 min to obtain the flower-shaped spherical silver powder.

[0013] Among them, the specific surface area of the flower-shaped spherical silver powder is greater than or equal to 0.9 m 2 / g.

[0014] The embodiment of the present application also provides a flower-shaped spherical silver powder, which is prepared by using the preparation method of the flower-shaped spherical silver powder in any one of the above.

[0015] The flower-shaped spherical silver powder and its preparation method provided by the present application, by preparing a first solution and a second solution, the first solution includes silver nitrate, and the second solution includes a reducing agent, a dispersant, and a surfactant. Then, after adjusting the pH value of the second solution to a preset value, it is added to the first solution for reaction to obtain a silver powder suspension, the preset value is 3 - 7. After that, the flower-shaped spherical silver powder is separated from the silver powder suspension. The flower-shaped spherical silver powder is a spherical silver powder with a flower-shaped structure. Thus, by introducing a surfactant, a flower-shaped spherical silver powder with a large specific surface area can be prepared. The preparation process is simple, and the morphology and size of the flower-shaped spherical silver powder can be effectively regulated by changing the dosage and / or type of the surfactant. Moreover, the flower-shaped spherical silver powder can effectively avoid agglomeration and bridging effects, ensuring good dispersibility and uniformity of the flower-shaped spherical silver powder, and having good application prospects in multiple fields such as conductive pastes and conductive coatings. Brief Description of the Drawings

[0016] The following, in conjunction with the drawings, through a detailed description of the specific embodiments of the present application, will make the technical solutions and other beneficial effects of the present application obvious.

[0017] Figure 1 It is a schematic flowchart of a method for preparing flower-shaped spherical silver powder provided by an embodiment of the present application;

[0018] Figure 2 It is a scanning electron microscope image of the flower-shaped spherical silver powder prepared by the method for preparing flower-shaped spherical silver powder provided in Embodiment 1 of the present application;

[0019] Figure 3 It is a scanning electron microscope image of the flower-shaped spherical silver powder prepared by the method for preparing flower-shaped spherical silver powder provided in Embodiment 2 of the present application;

[0020] Figure 4 It is a scanning electron microscope image of the flower-shaped spherical silver powder prepared by the method for preparing flower-shaped spherical silver powder provided in Embodiment 3 of the present application. Detailed Description of the Embodiments

[0021] The following, in conjunction with the drawings and embodiments, will further describe the present application in detail. It should be particularly noted that the following embodiments are only used to illustrate the present application, but do not limit the scope of the present application. Similarly, the following embodiments are only some embodiments of the present application rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0022] In the following description of the present application, reference is made to "some embodiments", which describe a subset of all possible embodiments. However, it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0023] In the following description of the present application, the terms "first / second / third" are only used to distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first / second / third" can be interchanged in a specific order or sequence when allowed, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0025] The following will be described in detail with specific embodiments. It should be noted that the serial numbers of the following embodiments are not intended to limit the preferred order of the embodiments.

[0026] Please refer to Figure 1 , Figure 1 which is a schematic flow chart of the preparation method of the flower-shaped spherical silver powder provided by the embodiments of the present application. The specific process of the preparation method of the flower-shaped spherical silver powder can be as follows:

[0027] Step S11. Prepare a first solution and a second solution. The first solution includes silver nitrate, and the second solution includes a reducing agent, a dispersant, and a surfactant.

[0028] In this embodiment, the mass concentration of silver nitrate in the first solution can be 5-25%. In some examples, the mass concentration of silver nitrate in the first solution can be specifically 5-15%. For example, it can be 5%, 10%, or 15%, etc. The mass concentration of the reducing agent in the second solution can be 10-20%. For example, it can be 10%, 15%, or 20%, etc. The mass ratio of the reducing agent in the second solution to the silver nitrate in the first solution can be 50-60%. For example, it can be 50%, 52%, 54%, 56%, 58%, or 60%, etc. The mass ratio of the dispersant in the second solution to the silver nitrate in the first solution can be 5-20%. For example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%, etc. The mass ratio of the surfactant in the second solution to the silver nitrate in the first solution can be 0.5-5%. For example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, or 5.0%, etc.

[0029] Specifically, the reducing agent can include at least one of glucose, ascorbic acid, hydrazine hydrate, hydrogen peroxide, formaldehyde, and acetaldehyde. For example, it can be specifically ascorbic acid. The dispersant can include at least one of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, arabic gum, gelatin, and tween. For example, it can be specifically polyvinylpyrrolidone. The surfactant can include at least one of silane coupling agent, span, oleic acid, sodium dodecylbenzenesulfonate, methylbenzotriazole, and benzotriazole. For example, it can be specifically sodium dodecylbenzenesulfonate or benzotriazole.

[0030] In some embodiments, the method for preparing the first solution can be specifically: adding silver nitrate to ultrapure water and stirring to dissolve to obtain the first solution. And, in specific implementation, 5 kg of silver nitrate solid can be added to ultrapure water and stirred to dissolve to obtain a silver nitrate solution with a mass fraction of 5% (i.e., the first solution).

[0031] In some embodiments, the method for preparing the second solution may specifically be: adding a reducing agent, a dispersant, and an appropriate amount of surfactant to ultrapure water, and stirring and dissolving to obtain the second solution. Specifically, during implementation, 2.6 kg of ascorbic acid solid may be added as the reducing agent to ultrapure water, and stirred and dissolved to obtain a reducing agent solution with a mass fraction of 15%. Then, 300 g of polyvinylpyrrolidone may be added as the dispersant to the reducing agent solution, and 30 g of sodium dodecylbenzenesulfonate may be added as the surfactant. After stirring evenly, the second solution can be obtained.

[0032] In some embodiments, the method for preparing the above-mentioned flower-shaped spherical silver powder may further include: controlling the temperatures of the first solution and the second solution at 25 - 45 °C. For example, it can be controlled at 25 °C, 30 °C, 35 °C, 40 °C, or 45 °C, etc. In this way, the reaction temperature of the first solution and the second solution in subsequent step S12 can be controlled, and further, the morphology of the desired silver powder can be controlled. Moreover, the inventors of the present application found that the higher the reaction temperature of the first solution and the second solution in subsequent step S12, the looser the aggregation of the corresponding prepared microcrystalline silver powder.

[0033] Step S12. After adjusting the pH value of the second solution to a preset value, add it to the first solution for reaction to obtain a silver powder suspension, and the preset value is 3 - 7.

[0034] Among them, the preset value may specifically be 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, or 7, etc.

[0035] In some embodiments, the above-mentioned step S12 may include: after adjusting the pH value of the second solution to a preset value by adding a pH regulator to the second solution, add it to the first solution for reaction to obtain a silver powder suspension. Among them, the pH regulator may include at least one of ammonia water, sodium hydroxide, sodium bicarbonate, oxalic acid, phosphoric acid, nitric acid, hydrochloric acid, and sulfuric acid. For example, it may specifically be ammonia water and / or nitric acid.

[0036] In some embodiments, the above-mentioned step S12 may include: after adjusting the pH value of the second solution to a preset value, add it to the first solution for reaction under stirring conditions within a preset addition time to obtain a silver powder suspension. Among them, the preset addition time (that is, the duration for adding the second solution to the first solution) may be 5 - 15 min. In some examples, the preset addition time may specifically be 5 - 10 min. For example, it may be 5 min, 6 min, 7 min, 8 min, 9 min, or 10 min, etc.

[0037] In some embodiments, the above step S12 may include: after adjusting the pH value of the second solution to a preset value, adding it to the first solution for reaction under the condition of a preset reaction temperature to obtain a silver powder suspension. The preset reaction temperature may be 25 to 45 °C. For example, it may specifically be 25 °C, 30 °C, 35 °C, 40 °C, or 45 °C, etc. Specifically, the inventors of the present application found that the higher the preset reaction temperature (i.e., the reaction temperature of the first solution and the second solution), the looser the aggregation of the prepared microcrystalline silver powder. And during specific implementation, the reaction temperature of the first solution and the second solution in the above step S12 can be controlled at the preset reaction temperature by controlling the temperatures of the first solution and the second solution prepared in the above step S11 at the preset reaction temperature.

[0038] In some specific embodiments, the temperatures of the first solution and the second solution prepared in the above step S11 are controlled at the preset reaction temperature (such as 25 °C or 45 °C), and the above step S12 may include: adding a pH regulator (such as ammonia water) to the second solution to adjust the pH value of the second solution to 3 to 7 (such as about 5), and then adding the second solution to the first solution for reaction under stirring conditions with a feeding time of 5 to 10 min (such as 8 min). After adding, continue stirring and reacting for 5 to 15 min (such as 10 min) to obtain a silver powder suspension.

[0039] Step S13: Separate the flower-shaped spherical silver powder from the silver powder suspension. The flower-shaped spherical silver powder is a spherical silver powder with a flower-shaped structure.

[0040] It should be noted that due to its unique structural characteristics, the flower-shaped spherical silver powder obtained after the completion of the above step S13 can provide a larger specific surface area and better electrical conductivity, so it has great application potential in fields such as advanced electronic devices and efficient catalysts.

[0041] Moreover, compared with the method in the related art of increasing the specific surface area of silver powder by increasing the surface roughness of silver powder, for example, by introducing a new dispersant, crystal form interfering agent, or other reagents to regulate the growth mode of silver powder to make its surface rough, in this embodiment, by introducing a surfactant to control the crystal plane growth to regulate the morphology of silver powder, it can play a similar growth regulation role on silver powder to prepare a spherical silver powder with a special flower-shaped structure (i.e., flower-shaped spherical silver powder). Due to its rough surface and many protruding structures, the flower-shaped spherical silver powder can have a larger specific surface area and higher sintering activity, and has broad application prospects in the field of photovoltaic silver paste. And the raw materials used in its preparation are simple, and its preparation method is simple, which is conducive to reducing production costs.

[0042] In this embodiment, the flower-shaped spherical silver powder obtained after the above step S13 has a flower-shaped structure, and its specific surface area can be greater than or equal to 0.9 m 2 / g. Moreover, it can be understood that due to the flower-shaped structure extending from its surface, its specific surface area is relatively large, which is beneficial to improving its sintering activity.

[0043] In some embodiments, the above step S13 may include: separating the solid and liquid of the silver powder suspension, washing the separated solid, and drying the washed solid to obtain the flower-shaped spherical silver powder. Among them, the drying temperature can be 40-60 °C. For example, it can be specifically 40 °C, 45 °C, 50 °C, 55 °C or 60 °C, etc. The drying time can be 60-120 min. For example, it can be specifically 60 min, 70 min, 80 min, 90 min, 100 min, 110 min or 120 min, etc. The method for separating the solid and liquid of the silver powder suspension can be specifically: separating the solid and liquid in the silver powder suspension by filtration. The method for washing the separated solid can be specifically: washing the separated solid with ultrapure water.

[0044] In some specific embodiments, the above step S13 may include: separating the solid and liquid of the silver powder suspension, washing the separated solid with ultrapure water, and transferring the washed solid to an oven for drying. The drying temperature can be 40-60 °C (for example, 60 °C), and the drying time can be 60-120 min (for example, 120 min). After drying, the target product (i.e., the above flower-shaped spherical silver powder) can be obtained.

[0045] It can be understood that all raw materials used in the embodiments of the present application can be obtained commercially.

[0046] Moreover, for the convenience of understanding, the present application will be further described in detail below through three specific embodiments (i.e., Embodiment 1, Embodiment 2, and Embodiment 3).

[0047] Embodiment 1

[0048] In Embodiment 1, the specific process of the preparation method of the flower-shaped spherical silver powder can be as follows:

[0049] Step S21. Prepare the first solution and the second solution, including: weighing 5 kg of silver nitrate solid and preparing a silver nitrate solution with a mass fraction of 5% to obtain the first solution; weighing 2.6 kg of ascorbic acid solid and preparing a reducing agent solution with a mass fraction of 15%. Then, add 300 g of polyvinylpyrrolidone as a dispersant and 30 g of sodium dodecylbenzenesulfonate as a surfactant to the reducing agent solution, and stir evenly to obtain the second solution; control the temperatures of the first solution and the second solution at about 25 °C.

[0050] Step S22. Add ammonia water to the second solution to adjust the pH value of the second solution to about 5. Then, under stirring conditions, add the second solution to the first solution and finish adding it within 8 min. After finishing the addition, react for 10 min to obtain a silver powder suspension.

[0051] Step S23. Separate the solid and liquid of the silver powder suspension, wash the separated solid with ultrapure water, and place the washed solid in an oven at 60 °C for 120 min to obtain the target product (i.e., flower-like spherical silver powder A1).

[0052] Specifically, from the scanning electron microscope image of the flower-like spherical silver powder A1 (as Figure 2 shown), it can be seen that the flower-like spherical silver powder A1 is a spherical silver powder with a special flower-like structure. And by measuring its surface area through the gas adsorption method, its specific surface area is 0.9 m 2 / g.

[0053] Example 2

[0054] The preparation method of the flower-like spherical silver powder provided in Example 2 is basically the same as that provided in Example 1. The difference between the two is that: in Example 2, the surfactant added to the reducing agent solution is 30 g of benzotriazole instead of 30 g of sodium dodecylbenzenesulfonate. Correspondingly, in Example 2, the specific process of the preparation method of the flower-like spherical silver powder can be as follows:

[0055] Step S31. Prepare the first solution and the second solution, including: weigh 5 kg of silver nitrate solid and prepare a silver nitrate solution with a mass fraction of 5% to obtain the first solution; weigh 2.6 kg of ascorbic acid solid, prepare a reducing agent solution with a mass fraction of 15%, then add 300 g of polyvinylpyrrolidone as a dispersant and 30 g of benzotriazole as a surfactant to the reducing agent solution, and stir evenly to obtain the second solution; control the temperature of the first solution and the second solution at about 25 °C.

[0056] Step S32. Add ammonia water to the second solution to adjust the pH value of the second solution to about 5. Then, under stirring conditions, add the second solution to the first solution and finish adding it within 8 min. After finishing the addition, react for 10 min to obtain a silver powder suspension.

[0057] Step S33. Separate the solid and liquid of the silver powder suspension, wash the separated solid with ultrapure water, and place the washed solid in an oven at 60 °C for 120 min to obtain the target product (i.e., flower-like spherical silver powder A2).

[0058] Specifically, from the scanning electron microscope image of the flower-shaped spherical silver powder A2 (as Figure 3 shown), it can be seen that the flower-shaped spherical silver powder A2 is a spherical silver powder with a special flower-like structure. Moreover, by comparing the scanning electron microscope image of the flower-shaped spherical silver powder A2 with that of the flower-shaped spherical silver powder A1, that is, by comparing Figure 3 and Figure 2 it can be seen that in Example 2, the surfactant was changed, and the morphology and size of the obtained flower-shaped spherical silver powder A2 both changed significantly. For example, the sheet-like structures protruding from the surface of the flower-shaped spherical silver powder A2 became thinner. Thus, it can be known that by changing the surfactant, the morphology and size of the flower-shaped spherical silver powder can be effectively regulated, and the regulation method is simple.

[0059] Example 3

[0060] The preparation method of the flower-shaped spherical silver powder provided in Example 3 is basically the same as that provided in Example 1. The difference between the two is that in Example 3, the temperature of the first solution and the second solution is controlled at about 45 °C, rather than controlling the temperature of the first solution and the second solution at about 25 °C. Correspondingly, in Example 3, the specific process of the preparation method of the flower-shaped spherical silver powder can be as follows:

[0061] Step S41. Prepare the first solution and the second solution, including: Weigh 5 kg of silver nitrate solid and prepare a silver nitrate solution with a mass fraction of 5% to obtain the first solution; Weigh 2.6 kg of ascorbic acid solid and prepare a reducing agent solution with a mass fraction of 15%. Then, add 300 g of polyvinylpyrrolidone as a dispersant and 30 g of sodium dodecylbenzenesulfonate as a surfactant to the reducing agent solution, and stir evenly to obtain the second solution; Control the temperature of the first solution and the second solution at about 45 °C.

[0062] Step S42. Add ammonia water to the second solution to adjust the pH value of the second solution to about 5. Then, under stirring conditions, add the second solution to the first solution and finish adding it within 8 minutes. After adding, react for 10 minutes to obtain a silver powder suspension.

[0063] Step S43. Separate the solid and liquid of the silver powder suspension, wash the separated solid with ultrapure water, and place the washed solid in an oven at 60 °C for 120 minutes to obtain the target product (i.e., the flower-shaped spherical silver powder A3).

[0064] Specifically, from the scanning electron microscope image of the flower-shaped spherical silver powder A3 (as Figure 4 shown), it can be seen that the flower-shaped spherical silver powder A3 is a spherical silver powder with a special flower-like structure. Moreover, by comparing the scanning electron microscope image of the flower-shaped spherical silver powder A3 with that of the flower-shaped spherical silver powder A1, that is, by comparing Figure 4 andFigure 2 It can be seen that in Example 3, the reaction temperature of the first solution and the second solution was changed, and the morphology and size of the flower-shaped spherical silver powder A3 obtained were significantly changed. For example, the flaky structures protruding from the surface of the flower-shaped spherical silver powder A3 became longer. Thus, it can be seen that by changing the reaction temperature, the morphology and size of the flower-shaped spherical silver powder can be effectively regulated, and the regulation method is simple.

[0065] As can be seen from the above, the preparation method of the flower-shaped spherical silver powder provided in this embodiment includes preparing a first solution and a second solution. The first solution includes silver nitrate, and the second solution includes a reducing agent, a dispersant, and a surfactant. Then, after adjusting the pH value of the second solution to a preset value, it is added to the first solution for reaction to obtain a silver powder suspension. The preset value is 3-7. After that, the flower-shaped spherical silver powder is separated from the silver powder suspension. The flower-shaped spherical silver powder is a spherical silver powder with a flower-shaped structure. Thus, by introducing a surfactant, a flower-shaped spherical silver powder with a large specific surface area can be prepared. The preparation process is simple, and by changing the dosage and / or type of the surfactant, the morphology and size of the flower-shaped spherical silver powder can be effectively regulated. Moreover, the flower-shaped spherical silver powder can effectively avoid agglomeration and bridging effects, ensuring good dispersibility and uniformity of the flower-shaped spherical silver powder, and having good application prospects in many fields such as conductive pastes and conductive coatings.

[0066] To better implement the preparation method of the flower-shaped spherical silver powder provided in the embodiments of the present application, the embodiments of the present application also provide a flower-shaped spherical silver powder (such as Figure 2 、 Figure 3 or Figure 4 shown), which is prepared by using the preparation method of the flower-shaped spherical silver powder provided in any of the above embodiments.

[0067] Specifically, due to its rough surface and many protruding structures, the flower-shaped spherical silver powder can have a large specific surface area and high sintering activity, and has broad application prospects in the field of photovoltaic silver paste.

[0068] In some embodiments, the specific surface area of the flower-shaped spherical silver powder can be greater than or equal to 0.9 m 2 / g.

[0069] Moreover, it should be noted that since the flower-shaped spherical silver powder in the embodiments of the present application is prepared by using the preparation method of the flower-shaped spherical silver powder provided in any of the above embodiments, it has all the same beneficial effects, which will not be elaborated in this embodiment.

[0070] In the above embodiments, the descriptions of each embodiment have their own focuses. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0071] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A method for preparing flower-shaped spherical silver powder, characterized in that: include: Prepare a first solution and a second solution, wherein the first solution includes silver nitrate, and the second solution includes a reducing agent, a dispersant, and a surfactant, wherein the mass concentration of the silver nitrate in the first solution is 5-25%, the mass concentration of the reducing agent in the second solution is 10-20%, and the mass ratio of the reducing agent in the second solution to the mass of the silver nitrate in the first solution is 50-60%; the mass ratio of the dispersant in the second solution to the mass of the silver nitrate in the first solution is 5-20%; the mass ratio of the surfactant in the second solution to the mass of the silver nitrate in the first solution is 0.5-5%, and the surfactant includes at least one of a silane coupling agent, span, oleic acid, sodium dodecylbenzene sulfonate, tolyltriazole, and benzotriazole; After adjusting the pH value of the second solution to a preset value, adding the second solution to the first solution for reaction to obtain a silver powder suspension, wherein the preset value is 4.5 to 7; Separating flower-shaped spherical silver powder from the silver powder suspension, wherein the flower-shaped spherical silver powder is a quasi-spherical silver powder with a flower-shaped structure; The step of adjusting the pH value of the second solution to a preset value and then adding the second solution to the first solution for reaction to obtain a silver powder suspension comprises: After the pH value of the second solution is adjusted to a preset value, it is added to the first solution for reaction under preset reaction temperature and stirring conditions within a preset addition time to obtain a silver powder suspension, wherein the preset reaction temperature is 25 to 45°C, and the preset addition time is 5 to 15 minutes.

2. The preparation method according to claim 1, characterized in that: The reducing agent includes at least one of glucose, ascorbic acid, hydrazine hydrate, hydrogen peroxide, formaldehyde and acetaldehyde; the dispersant includes at least one of polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene glycol, gum arabic, gelatin and Tween.

3. The preparation method according to claim 1, characterized in that: The surfactant is sodium dodecylbenzene sulfonate or benzotriazole.

4. The preparation method according to claim 1, characterized in that: After adjusting the pH value of the second solution to a preset value, adding the second solution to the first solution for reaction to obtain a silver powder suspension comprises: The pH value of the second solution is adjusted to a preset value by adding a pH adjuster to the second solution, and then added to the first solution for reaction to obtain a silver powder suspension; the pH adjuster includes at least one of ammonia water, sodium hydroxide, sodium bicarbonate, oxalic acid, phosphoric acid, nitric acid, hydrochloric acid and sulfuric acid.

5. The preparation method according to claim 1, characterized in that: The method of separating flower-shaped spherical silver powder from the silver powder suspension comprises: The silver powder suspension is separated into solid and liquid, the separated solid is washed, and the washed solid is dried at a drying temperature of 40 to 60° C. for 60 to 120 minutes to obtain flower-shaped spherical silver powder.

6. The preparation method according to claim 1, characterized in that: The specific surface area of ​​the flower-shaped spherical silver powder is greater than or equal to 0.9 m 2 / g.

7. A flower-shaped spherical silver powder, characterized in that: The method is prepared by the preparation method according to any one of claims 1 to 6.

Images