Modified silver powder and preparation method thereof

Abstract

The invention provides modified silver powder and a preparation method thereof. The preparation method of the modified silver powder comprises the following steps that (1) the silver powder is subjected to acid treatment, so that the surface of the silver powder is positively charged; (2) the silver powder subjected to acid treatment and the anionic polyelectrolyte aqueous solution are placed in a container, and oscillation is stopped after oscillation treatment is carried out for a first preset time at a first preset temperature and a first preset speed; (3) adding an inorganic oxide modified material into the container, carrying out vibration treatment at a second preset temperature and a second preset speed for a second preset time, and stopping vibration; and (4) the system in the container treated in the step (3) is subjected to centrifugal cleaning, obtained precipitates are dried to obtain the modified silver powder, in the modified silver powder, anionic polyelectrolyte is attached to the surface of the silver powder, and an inorganic oxide modified material is attached to the anionic polyelectrolyte. The initial sintering temperature of the modified silver powder can be increased, so that the quality of the modified silver powder is improved.

Description

Technical Field

[0001] This invention relates to silver powder modification, and in particular to a modified silver powder and its preparation method. Background Technology

[0002] Modified silver powder has a wide range of applications in many fields due to its unique physical and chemical properties. Existing silver powder surface modification technologies are mainly chemical methods, such as silane coupling agent sol-gel method and chemical plating method. Because chemical reactions are limited by the activation energy of the reaction, the reaction conditions are harsh when the modified materials are attached to the surface of silver powder by chemical methods. This also limits the types of materials that can be used for silver powder surface modification. At the same time, it is not easy to control the degree of adhesion of the modified materials to control the initial sintering temperature of the modified silver powder when modifying silver powder by chemical methods.

[0003] It should be noted that the information disclosed in the background section above is only for understanding the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] This invention provides a modified silver powder and its preparation method.

[0005] The present invention adopts the following technical solution:

[0006] In a first aspect, a method for preparing modified silver powder is provided, comprising the following steps:

[0007] (1) The silver powder is acid-treated to make the surface of the silver powder positively charged;

[0008] (2) Place the acid-treated silver powder and anionic polyelectrolyte aqueous solution in a container, shake at a first predetermined temperature and a first predetermined speed for a first predetermined time, and then stop shaking.

[0009] (3) Add the inorganic oxide modified material into the container, and after shaking at a second predetermined temperature and a second predetermined speed for a second predetermined time, stop shaking;

[0010] (4) The system in the container after step (3) is centrifuged and cleaned, and the precipitate is dried to obtain the modified silver powder. In the modified silver powder, the anionic polyelectrolyte is attached to the surface of the silver powder, and the inorganic oxide modifying material is attached to the anionic polyelectrolyte.

[0011] Further, in step (1), the silver powder is treated with dilute hydrochloric acid for 1-5 hours, preferably with a concentration of 10 wt%.

[0012] Furthermore, the inorganic oxide modifying material is at least one of TiO2, SiO2, and Al2O3, preferably TiO2.

[0013] Further, the anionic polyelectrolyte is at least one selected from polyacrylic acid, polymethacrylic acid, sodium polyacrylate, sodium polymethacrylate, sodium polystyrene sulfonate, sodium alginate, and sodium carboxymethyl cellulose; preferably, the anionic polyelectrolyte is sodium polystyrene sulfonate.

[0014] Further, in step (2), the anionic polyelectrolyte aqueous solution is composed of the following components in the following mass percentages: 0.19% ± 0.02% anionic polyelectrolyte, 2.86% ± 0.02% sodium chloride, and the balance being water.

[0015] Furthermore, in steps (2) and (3), the mass fraction of the acid-treated silver powder is 80%-95%, the mass fraction of the anionic polyelectrolyte aqueous solution is 1%-10%, and the mass fraction of the inorganic oxide modified material is 2%-20%.

[0016] Furthermore, in step (2), the first predetermined time is 1h-2h.

[0017] Furthermore, in step (3), the second predetermined time is 2h-24h.

[0018] Furthermore, in step (2), the first predetermined temperature is 25℃-80℃, and the first predetermined speed is 80r / min~300r / min.

[0019] Further, in step (3), the second predetermined temperature is 25℃-80℃, and the second predetermined speed is 80r / min~300r / min.

[0020] Furthermore, in step (4), the centrifugation speed is 8000rpm-10000rpm, and the drying is freeze drying.

[0021] Furthermore, the oscillation process in steps (2) and (3) is performed on a shaker.

[0022] In a second aspect, a modified silver powder is provided, comprising silver powder, an anionic polyelectrolyte, and an inorganic oxide modifier, wherein the anionic polyelectrolyte is attached to the surface of the silver powder, and the inorganic oxide modifier is attached to the anionic polyelectrolyte.

[0023] The present invention has the following beneficial effects: The present invention provides a silver powder modification method with adjustable initial sintering temperature and mild process. Through the method of the present invention, anionic polyelectrolytes are first electrostatically and hydrogenally adsorbed on positively charged silver powder, and then inorganic oxide modification materials are attached. This can improve the initial sintering temperature of silver powder. Compared with the existing harsh chemical reactions, the preparation method of the present invention is simple, low-cost, and mild, and can increase the initial sintering temperature of modified silver powder (i.e., the initial temperature at which modified silver powder shrinks as shown on the thermal expansion curve of modified silver powder), thereby improving the quality of modified silver powder and making modified silver powder applicable to different temperature scenarios.

[0024] In some embodiments, with the synergistic modification of the inorganic oxide modifier TiO2 and the anionic polyelectrolyte sodium polystyrene sulfonate, the initial sintering temperature of the modified silver powder can be increased to 400-600℃. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the modified silver powder in a specific embodiment of the present invention. Detailed Implementation

[0026] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0027] This invention provides a method for preparing modified silver powder, comprising the following steps:

[0028] (1) The silver powder is acid-treated to make the surface of the silver powder positively charged (the positive charge on the surface of the silver powder was confirmed by the Zeta potential test).

[0029] (2) Place the acid-treated silver powder and the anionic polyelectrolyte aqueous solution in a container, and shake it at a first predetermined temperature and a first predetermined speed for a first predetermined time, and then stop shaking. In this step (2), the anionic polyelectrolyte adheres to the surface of the silver powder through electrostatic and hydrogen bonding (mainly electrostatic), which increases the negative charge on the surface of the silver powder.

[0030] (3) Add the inorganic oxide modified material into the container, and after shaking for a second predetermined time at a second predetermined temperature and a second predetermined speed, stop shaking; the inorganic oxide modified material has positively charged cations in the solution, which can adhere to the negatively charged silver powder surface, thereby increasing the initial sintering temperature of the silver powder.

[0031] (4) The system in the container after step (3) is centrifuged and cleaned, and the precipitate is dried to obtain the modified silver powder. In the modified silver powder, the anionic polyelectrolyte is attached to the surface of the silver powder, and the inorganic oxide modifying material is attached to the anionic polyelectrolyte.

[0032] This invention employs a layer-by-layer self-assembly technology to modify silver powder. The principle is based on electrostatic adhesion and hydrogen bonding, allowing inorganic oxide modifiers, which can be used to adjust the sintering temperature of silver powder, to adhere to the silver powder surface under relatively mild physical conditions. This results in an increase in the initial sintering temperature of the silver powder, enabling the modified silver powder to be applied to different temperature scenarios. Specifically, this invention first acid-treats the silver powder to give its surface a positive charge. Then, a negatively charged anionic polyelectrolyte is adsorbed onto the acid-treated silver powder using intermaterial interactions (such as electrostatics and hydrogen bonding). Finally, the inorganic oxide modifier is also adsorbed onto the anionic polyelectrolyte using intermaterial interactions (such as electrostatics and hydrogen bonding). This inorganic oxide modification further increases the initial sintering temperature of the silver powder. The preparation method of this invention does not require harsh chemical reactions or expensive equipment; it is simple, low-cost, and operates under mild conditions.

[0033] In some embodiments, in step (1), the silver powder is treated with dilute hydrochloric acid for 1-5 hours, preferably with a concentration of 10 wt%.

[0034] In some embodiments, the inorganic oxide modifying material is at least one of TiO2, SiO2, and Al2O3.

[0035] In some embodiments, the inorganic oxide modifying material is TiO2, and under the condition of using TiO2, the initial sintering temperature of the modified silver powder can be increased to 400℃-600℃.

[0036] In some embodiments, the anionic polyelectrolyte is at least one selected from polyacrylic acid, polymethacrylic acid, sodium polyacrylate, sodium polymethacrylate, sodium polystyrene sulfonate, sodium alginate, and sodium carboxymethyl cellulose.

[0037] In some embodiments, the anionic polyelectrolyte is sodium polystyrene sulfonate.

[0038] In some embodiments, in step (2), the anionic polyelectrolyte aqueous solution is composed of the following components in the following mass percentages: 0.19% ± 0.02% anionic polyelectrolyte, 2.86% ± 0.02% sodium chloride, and the balance being water.

[0039] In some embodiments, in steps (2) and (3), the mass fraction of the acid-treated silver powder is 80%-95%, the mass fraction of the anionic polyelectrolyte aqueous solution is 1%-10%, and the mass fraction of the inorganic oxide modified material is 2%-20%.

[0040] In some implementations, in step (2), the first predetermined time is 1h-2h.

[0041] In some implementations, in step (3), the second predetermined time is 2h-24h.

[0042] In some embodiments, in step (2), the first predetermined temperature is 25°C-80°C, and the first predetermined speed is 80 r / min to 300 r / min.

[0043] In some embodiments, in step (3), the second predetermined temperature is 25°C-80°C, and the second predetermined speed is 80 r / min to 300 r / min.

[0044] In some implementations, the first predetermined temperature and the second predetermined temperature are the same, and the first predetermined speed and the second predetermined speed are the same.

[0045] In some embodiments, the centrifugation speed in step (4) is 8000 rpm-10000 rpm, and the drying is freeze drying.

[0046] In some implementations, the oscillation process in steps (2) and (3) is performed on a shaker.

[0047] The present invention also provides a modified silver powder, such as... Figure 1 As shown, it includes silver powder 1, anionic polyelectrolyte 2 and inorganic oxide modified material 3. The anionic polyelectrolyte 2 is attached to the surface of the silver powder 1, and the inorganic oxide modified material 3 is attached to the anionic polyelectrolyte 2.

[0048] The following further describes specific embodiments of the present invention. The anionic polyelectrolyte aqueous solution used in the various embodiments below consists of sodium polystyrene sulfonate with a mass fraction of 0.19% ± 0.02%, sodium chloride with a mass fraction of 2.86% ± 0.02%, and the balance being water.

[0049] Example 1

[0050] Methods for preparing modified silver powder include:

[0051] (1) After the silver powder is treated with 10% dilute hydrochloric acid for 1 hour, it is washed and dried. The surface of the silver powder after dilute hydrochloric acid treatment carries a positive charge.

[0052] (2) Weigh the acid-treated silver powder and anionic polyelectrolyte aqueous solution according to the proportion and place them in a stoppered conical flask (e.g., a 150ml conical flask). After fixing the conical flask to the shaker, set the temperature (25℃) and speed (80r / min), and start the shaker treatment for 1 hour. Through the treatment of the shaker, sodium polystyrene sulfonate adheres to the surface of the silver powder through electrostatic and hydrogen bonding (mainly electrostatic interaction), which increases the negative charge on the surface of the silver powder.

[0053] (3) Add TiO2 to the conical flask, restart the shaker for 2 hours, and then stop the shaker. In this step, the metal element in TiO2 in the solution carries a positive charge and can adhere to the surface of the anionic polyelectrolyte, thereby increasing the initial sintering temperature of the silver powder. In this example, the mass fraction of the acid-treated silver powder is 80%, the mass fraction of the anionic polyelectrolyte aqueous solution is 1%, and the mass fraction of TiO2 is 19%.

[0054] (4) Transfer the system in the conical flask to a centrifuge tube for centrifugation (8000 rpm to 10000 rpm). The precipitated silver powder is washed by centrifugation (washed three times by centrifugation with water and ethanol). The precipitate after washing is freeze-dried to obtain modified silver powder.

[0055] The initial sintering temperature of the modified silver powder in this embodiment was determined to be 460°C using a thermal expansion coefficient analyzer (TMA).

[0056] Example 2

[0057] Methods for preparing modified silver powder include:

[0058] (1) After the silver powder is treated with 10% dilute hydrochloric acid for 5 hours, it is washed and dried.

[0059] (2) Weigh the acid-treated silver powder and anionic polyelectrolyte aqueous solution according to the proportion and place them in a stoppered conical flask. After fixing the conical flask to the shaker, set the temperature (25℃) and speed (80r / min) and start the shaker to process for 1 hour.

[0060] (3) Add TiO2 to the conical flask, restart the shaker for 2 hours, and then stop shaking. In this example, the mass fraction of the acid-treated silver powder is 80%, the mass fraction of the anionic polyelectrolyte aqueous solution is 1%, and the mass fraction of TiO2 is 19%.

[0061] (4) Transfer the system in the conical flask to a centrifuge tube for centrifugation (8000 rpm to 10000 rpm). The precipitated silver powder is washed by centrifugation (washed three times by centrifugation with water and ethanol). The precipitate after washing is freeze-dried to obtain modified silver powder.

[0062] The initial sintering temperature of the modified silver powder in this embodiment was determined to be 510°C by thermal expansion coefficient analyzer (TMA).

[0063] Example 3

[0064] Methods for preparing modified silver powder include:

[0065] (1) After the silver powder is treated with 10% dilute hydrochloric acid for 5 hours, it is washed and dried.

[0066] (2) Weigh the acid-treated silver powder and anionic polyelectrolyte aqueous solution according to the proportion and place them in a stoppered conical flask. After fixing the conical flask to the shaker, set the temperature (25℃) and speed (80r / min) and start the shaker to process for 1 hour.

[0067] (3) Add TiO2 to the conical flask, restart the shaker for 2 hours, and then stop shaking. In this example, the mass fraction of the acid-treated silver powder is 94%, the mass fraction of the anionic polyelectrolyte aqueous solution is 1%, and the mass fraction of TiO2 is 5%.

[0068] (4) Transfer the system in the conical flask to a centrifuge tube for centrifugation (8000-10000 rpm). The precipitated silver powder is washed by centrifugation (washed three times by centrifugation with water and ethanol). The precipitate after washing is freeze-dried to obtain modified silver powder.

[0069] The initial sintering temperature of the modified silver powder in this embodiment was determined to be 490°C by thermal expansion coefficient analyzer (TMA).

[0070] Example 4

[0071] Methods for preparing modified silver powder include:

[0072] (1) After the silver powder is treated with 10% dilute hydrochloric acid for 5 hours, it is washed and dried.

[0073] (2) Weigh the acid-treated silver powder and anionic polyelectrolyte aqueous solution according to the proportion and place them in a stoppered conical flask. After fixing the conical flask to the shaker, set the temperature (25℃) and speed (80r / min) and start the shaker to process for 1 hour.

[0074] (3) Add TiO2 (15 wt%) to the conical flask, restart the shaker for 2 hours, and then stop shaking. In this example, the mass fraction of the acid-treated silver powder is 80%, the mass fraction of the anionic polyelectrolyte aqueous solution is 5%, and the mass fraction of TiO2 is 15%.

[0075] (4) Transfer the system in the conical flask to a centrifuge tube for centrifugation (8000 rpm to 10000 rpm). The precipitated silver powder is washed by centrifugation (washed three times by centrifugation with water and ethanol). The precipitate after washing is freeze-dried to obtain modified silver powder.

[0076] The initial sintering temperature of the modified silver powder in this embodiment was determined to be 540°C by thermal expansion coefficient analyzer (TMA).

[0077] Example 5

[0078] Methods for preparing modified silver powder include:

[0079] (1) After the silver powder is treated with 10% dilute hydrochloric acid for 5 hours, it is washed and dried.

[0080] (2) Weigh the acid-treated silver powder and anionic polyelectrolyte aqueous solution according to the proportion and place them in a stoppered conical flask. After fixing the conical flask to the shaker, set the temperature (25℃) and speed (80r / min) and start the shaker to process for 1 hour.

[0081] (3) Add TiO2 to the conical flask, restart the shaker for 2 hours, and then stop shaking. In this example, the mass fraction of the acid-treated silver powder is 80%, the mass fraction of the anionic polyelectrolyte aqueous solution is 10%, and the mass fraction of TiO2 is 10%.

[0082] (4) Transfer the system in the conical flask to a centrifuge tube for centrifugation (8000 rpm to 10000 rpm). The precipitated silver powder is washed by centrifugation (washed three times by centrifugation with water and ethanol). The precipitate after washing is freeze-dried to obtain modified silver powder.

[0083] The initial sintering temperature of the modified silver powder in this embodiment was determined to be 580°C by thermal expansion coefficient analyzer (TMA).

[0084] Example 6

[0085] Methods for preparing modified silver powder include:

[0086] (1) After the silver powder is treated with 10% dilute hydrochloric acid for 5 hours, it is washed and dried.

[0087] (2) Weigh the acid-treated silver powder and anionic polyelectrolyte aqueous solution according to the proportion and place them in a stoppered conical flask. After fixing the conical flask to the shaker, set the temperature (80℃) and speed (80r / min) and start the shaker to process for 1 hour.

[0088] (3) Add TiO2 to the conical flask, restart the shaker for 2 hours, and then stop shaking. In this example, the mass fraction of the acid-treated silver powder is 80%, the mass fraction of the anionic polyelectrolyte aqueous solution is 1%, and the mass fraction of TiO2 is 19%.

[0089] (4) Transfer the system in the conical flask to a centrifuge tube for centrifugation (8000 rpm to 10000 rpm). The precipitated silver powder is washed by centrifugation (washed three times by centrifugation with water and ethanol). The precipitate after washing is freeze-dried to obtain modified silver powder.

[0090] The initial sintering temperature of the modified silver powder in this embodiment was determined to be 480°C by thermal expansion coefficient analyzer (TMA).

[0091] Example 7

[0092] Methods for preparing modified silver powder include:

[0093] (1) After the silver powder is treated with 10% dilute hydrochloric acid for 5 hours, it is washed and dried.

[0094] (2) Weigh the acid-treated silver powder and anionic polyelectrolyte aqueous solution according to the proportion and place them in a stoppered conical flask. After fixing the conical flask to the shaker, set the temperature (25℃) and speed (300r / min) and start the shaker to process for 1 hour.

[0095] (3) Add TiO2 to the conical flask, restart the shaker for 2 hours, and then stop shaking. In this example, the mass fraction of the acid-treated silver powder is 80%, the mass fraction of the anionic polyelectrolyte aqueous solution is 1%, and the mass fraction of TiO2 is 19%.

[0096] (4) Transfer the system in the conical flask to a centrifuge tube for centrifugation (8000 rpm to 10000 rpm). The precipitated silver powder is washed by centrifugation (washed three times by centrifugation with water and ethanol). The precipitate after washing is freeze-dried to obtain modified silver powder.

[0097] The initial sintering temperature of the modified silver powder in this embodiment was determined to be 550°C by thermal expansion coefficient analyzer (TMA).

[0098] Example 8

[0099] Methods for preparing modified silver powder include:

[0100] (1) After the silver powder is treated with 10% dilute hydrochloric acid for 5 hours, it is washed and dried.

[0101] (2) Weigh the acid-treated silver powder and anionic polyelectrolyte aqueous solution according to the proportion and place them in a stoppered conical flask. After fixing the conical flask to the shaker, set the temperature (25℃) and speed (80r / min) and start the shaker to process for 1 hour.

[0102] (3) Add TiO2 to the conical flask, restart the shaker for 24 hours, and then stop the shaker. In this example, the mass fraction of the acid-treated silver powder is 80%, the mass fraction of the anionic polyelectrolyte aqueous solution is 1%, and the mass fraction of TiO2 is 19%.

[0103] (4) Transfer the system in the conical flask to a centrifuge tube for centrifugation (8000 rpm to 10000 rpm). The precipitated silver powder is washed by centrifugation (washed three times by centrifugation with water and ethanol). The precipitate after washing is freeze-dried to obtain modified silver powder.

[0104] The initial sintering temperature of the modified silver powder in this embodiment was determined to be 580°C by thermal expansion coefficient analyzer (TMA).

[0105] Comparative Example

[0106] Methods for preparing modified silver powder include:

[0107] (1) After the silver powder is treated with 10% dilute hydrochloric acid for 1 hour, it is washed and dried.

[0108] (2) Weigh out the acid-treated silver powder and pure water according to the proportion and place them in a stoppered conical flask. After fixing the conical flask to the shaker, set the temperature (25℃) and speed (80r / min) and start the shaker to process for 1 hour.

[0109] (3) Add TiO2 to the conical flask, restart the shaker for 2 hours, and then stop shaking. In this example, the mass fraction of the acid-treated silver powder is 80%, the mass fraction of pure water is 1%, and the mass fraction of TiO2 is 19%.

[0110] (4) Transfer the system in the conical flask to a centrifuge tube for centrifugation (8000 rpm to 10000 rpm). The precipitated silver powder is washed by centrifugation (washed three times by centrifugation with water and ethanol). The precipitate after washing is freeze-dried to obtain modified silver powder.

[0111] The initial sintering temperature of the modified silver powder in this embodiment was measured to be 320°C using a thermal expansion coefficient analyzer (TMA). This initial sintering temperature is the same as that of the raw silver powder, indicating that the silver powder modification was unsuccessful without the participation of anionic polyelectrolytes, and the initial sintering temperature of the silver powder was not increased.

[0112] In addition to TiO2, the inorganic oxide modified material can also be SiO2 or Al2O3 in other embodiments. In addition to sodium polystyrene sulfonate, the anionic polyelectrolyte can also be at least one of polyacrylic acid, polymethacrylic acid, sodium polyacrylate, sodium polymethacrylate, sodium alginate, and sodium carboxymethyl cellulose. In these embodiments, silver powder can also be modified to increase the initial sintering temperature of the modified silver powder.

[0113] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A method for producing a modified silver powder, characterized by, The method comprises the following steps: (1) acid treating silver powder to make the surface of the silver powder positively charged; (2) placing the acid-treated silver powder and an aqueous solution of an anionic polyelectrolyte in a container, and oscillating the container at a first predetermined temperature and a first predetermined speed for a first predetermined time, and then stopping oscillation; (3) adding an inorganic oxide modifying material to the container, and oscillating the container at a second predetermined temperature and a second predetermined speed for a second predetermined time, and then stopping oscillation; (4) centrifuging the system in the container after step (3) to obtain a precipitate, and drying the precipitate to obtain the modified silver powder, wherein the anionic polyelectrolyte is attached to the surface of the silver powder, and the inorganic oxide modifying material is attached to the anionic polyelectrolyte.

2. The production method according to claim 1, characterized by: In step (1), the silver powder is treated with dilute hydrochloric acid for 1-5 hours, preferably the concentration of the dilute hydrochloric acid is 10 wt%.

3. The production method according to claim 1, wherein: The inorganic oxide modifying material is at least one of TiO2, SiO2, and Al2O3, and preferably the inorganic oxide modifying material is TiO2.

4. The production method according to claim 1, wherein: The anionic polyelectrolyte is at least one of polyacrylic acid, polymethacrylic acid, sodium polyacrylate, sodium polymethacrylate, sodium polystyrene sulfonate, sodium alginate, and sodium carboxymethyl cellulose, and preferably the anionic polyelectrolyte is sodium polystyrene sulfonate.

5. The production method according to claim 1, wherein: In step (2), the aqueous solution of the anionic polyelectrolyte is composed of the following components in the following mass percentages: 0.19%±0.02% anionic polyelectrolyte, 2.86%±0.02% sodium chloride, and the balance being water.

6. The production method according to claim 1, wherein: In steps (2) and (3), the mass fraction of the acid-treated silver powder is 80%-95%, the mass fraction of the aqueous solution of the anionic polyelectrolyte is 1%-10%, and the mass fraction of the inorganic oxide modifying material is 2%-20%.

7. The production method according to claim 1, wherein: In step (2), the first predetermined time is 1-2 hours.

8. The production method according to claim 1, wherein: In step (3), the second predetermined time is 2-24 hours.

9. The production method according to claim 1, wherein: In step (2), the first predetermined temperature is 25-80°C, and the first predetermined speed is 80-300 r / min.

10. The production method according to claim 1, wherein: In step (3), the second predetermined temperature is 25-80°C, and the second predetermined speed is 80-300 r / min.

11. The production method according to claim 1, wherein: In step (4), the centrifugation is performed at a speed of 8000-10000 rpm, and the drying is freeze-drying.

12. The production method according to claim 1, wherein: The oscillation treatment in steps (2) and (3) is performed on a shaking table.

13. A modified silver powder characterized in that, The modified silver powder comprises silver powder, an anionic polyelectrolyte attached to the surface of the silver powder, and an inorganic oxide modifying material attached to the anionic polyelectrolyte.

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