Method for preparing low-temperature sintered flaky silver powder by using monodisperse nano-silver

Abstract

The invention discloses a method for preparing low-temperature sintered flaky silver powder by using monodisperse nano-silver. The method comprises the following steps: (1) selecting prepared monodisperse nano-silver as a raw material; (2) emulsifying the silver powder prepared in the step (1) in a dispersion machine; (3) the silver powder emulsified in the step (2) is put into a filter press for solid-liquid separation; (4) the silver powder obtained after solid-liquid separation in the step (3) is put into a freeze dryer to be freeze-dried; (5) the freeze-dried silver powder in the step (4) is sieved and put into a ball mill for ball milling; and (6) carrying out ball milling for 3 hours, detecting the particle size D50 to be 0.6-0.8 mu m, discharging, carrying out ball-material separation, freeze-drying and sieving to obtain a finished product. The prepared flaky silver powder is good in dispersity, small in flaky shape, good in conductivity, capable of being sintered at low temperature, suitable for low-temperature conductive silver paste and low-temperature sintered silver paste, and capable of being used for low-temperature touch screen silver paste, conductive adhesive and HJT solar cell electrode silver paste.

Description

Technical Field

[0001] The invention relates to the technical field of electronic material functional powder precious metal powder silver powder, and relates to a method for preparing low-temperature sintered flaky silver powder by using monodisperse nano silver. Background Art

[0002] At present, the main preparation methods of flaky silver powder are chemical reduction method and mechanical ball milling method. Chemical reduction method is usually prepared and synthesized by chemical reaction in water phase or organic phase. Since water is a polar substance and is not lipophilic, and has strong hydrogen bonds, only amphiphilic molecules can be added to participate in the reaction. The added chemical components are complex, so the synthesized flaky silver powder is not monodisperse. It is usually a flaky silver powder with short radial growth on the surface of silver grains, poor conductivity, low sintering activity, and similar flaky agglomerated particles during the reaction process. Therefore, it is difficult to prepare truly monodisperse flaky silver powder and difficult to achieve industrial production.

[0003] At present, there have been related studies. For example, Chinese patent application No. 202410373020.7 discloses a low-loose flaky silver powder and its preparation method and application. Wet silver powder, dispersant, and grinding aid are mixed and dispersed to obtain a precursor slurry; the precursor slurry is subjected to a first-stage ball milling, placed and soaked, and a second-stage ball milling to obtain a flake silver slurry; the flake silver slurry is washed, allowed to stand, precipitated, and dried to obtain a low-loose flaky silver powder with a particle size D 50 5μm or more.

[0004] Chinese patent application No. 202311557114.1 discloses a high tap density flaky overlapping silver powder and a preparation method thereof, which comprises a 0.50-2.0 M sulfate solution and a 1.5-3.0 M silver nitrate solution; a first organic acid, a second organic acid and a 35-45% volume sulfate solution are added to a reaction vessel, stirring is started, and the temperature is controlled at 5-30°C. Under stirring, the silver nitrate solution and a 55-65% volume sulfate solution are simultaneously added dropwise to the reaction vessel, stirring is continued for 10-15 minutes, and then separated, washed and dried to obtain a high tap density flaky overlapping silver powder with an average particle size of more than 3.5 μm.

[0005] Chinese patent application No. 202211313470.4 discloses a method for preparing flaky silver powder, wherein solution A and solution B are mixed and reacted to prepare the flaky silver powder; solution A includes Ag + , silver nanosheet seeds and Ce with oxidation 4+ or Fe 3+ At least one ion in solution B includes SO4 2- or at least one ion of citrate; D of silver powder 50 2-3μm.

[0006] Currently, the flaky silver powder on the market is generally obtained by mechanical ball milling. This type of flake powder is generally large and can achieve low-temperature conductivity when used in ordinary keyboard paste. This is because the resin carrier shrinks and shrinks the flake powder together to achieve overlap between the flakes to achieve low-temperature conductivity, but it cannot achieve low-temperature sintering. Flake powder has a single purpose. It is difficult for the same silver powder to be used for both low-temperature conductive and low-temperature sintering silver pastes. Silver powder D used for low-temperature conductive silver paste 50 6-8μm, good conductivity but too large particle size, low temperature drying meets the conductivity requirements, but cannot achieve low temperature sintering; low temperature sintering requires <300℃ silver powder, which can achieve sintering and welding to have good conductivity and adhesion, silver powder requires D 50 <0.8μm flake powder, currently mainly imported silver powder is used. Summary of the invention

[0007] Aiming at the problem that the flaky silver powder in the prior art has a single use and the same silver powder is difficult to be used for both low-temperature conductive silver paste and low-temperature sintering silver paste, the technical problem to be solved is how to provide a small flaky silver powder that can be used for both low-temperature conductive silver paste and low-temperature sintering silver paste. The present invention provides a method for preparing low-temperature sintered small flaky silver powder using monodisperse nanosilver. The small flaky silver powder prepared by the method has good dispersibility, small flaking, good conductivity, and can be sintered at low temperature. The small flaky silver powder is suitable for both low-temperature conductive silver paste and low-temperature sintering silver paste, and can be used for low-temperature touch screen silver paste, conductive adhesive, and HJT solar cell electrode silver paste.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver comprises the following steps:

[0010] (1) Selecting prepared monodispersed nanosilver as raw material;

[0011] (2) emulsifying the silver powder prepared in step (1) in a disperser;

[0012] (3) placing the emulsified silver powder in step (2) into a filter press for solid-liquid separation;

[0013] (4) placing the silver powder separated from the solid and liquid in step (3) into a freeze dryer for freeze drying;

[0014] (5) sieving the freeze-dried silver powder in step (4) and putting it into a ball mill for ball milling;

[0015] (6) Ball milling for 3 hours to measure particle size D 50 0.6-0.8μm discharge, ball separation, freeze-drying and sieving to obtain the finished product.

[0016] The present invention relates to a method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver, comprising the following steps:

[0017] 1) First, add an alcohol solvent equivalent to 2 times the mass of the monodisperse nanosilver powder into a disperser, then add the prepared monodisperse nanosilver, and perform emulsification treatment in the disperser for 10-20 minutes;

[0018] The alcohol solvent is selected from one of glycerol, diethylene glycol, anhydrous ethanol, ethylene glycol, and isopropanol;

[0019] The monodisperse nano silver powder has a particle size D 50 0.3-0.5μm, specific surface area 1.8-2.2m 2 / g;

[0020] 2) dissolving a fatty acid equivalent to 0.4-0.6% of the mass of the monodisperse nano-silver powder in an alcohol solvent equivalent to 4-5 times the mass of the monodisperse nano-silver powder to completely dissolve it into solution A;

[0021] The fatty acid is selected from palmitic acid, oleic acid, oleyl glyceryl, stearic acid, stearyl glyceryl, and hexadecanol;

[0022] 3) Add all of solution A into the emulsifier in step 1), stir thoroughly for 10-30 minutes to obtain uniformly emulsified silver powder;

[0023] 4) putting the emulsified silver powder in the previous step into a filter press for filtering;

[0024] 5) Place the filtered silver powder in a freeze dryer and dry it at a freezing temperature of -80°C and a drying temperature of 35°C;

[0025] 6) The freeze-dried silver powder was passed through a 100-mesh sieve and directly connected to a ball mill for mechanical ball milling;

[0026] 7) After ball milling, check the particle size D 50 0.6-0.8μm passed through a 350 mesh sieve to obtain low-temperature sintered small flake silver powder, which can be used for both low-temperature conductive silver paste and low-temperature sintered silver paste. The bulk density of the silver powder is 1.7-3.0g / cm 3 , tap density 3.0-5.0g / cm 3 , particle size D 50 0.3-0.8μm, specific surface area 2.0-3.0m 2 / g.

[0027] In the present invention:

[0028] Furthermore, the step 1) of adding an alcohol solvent in a volume equivalent to 2 times the mass of the monodisperse nano-silver powder is in accordance with a ratio of 1 kg of monodisperse nano-silver powder: 2 L of alcohol solvent, the same below.

[0029] Furthermore, in the filter pressing described in step 4), the filter pressing air does not contain moisture and the air pressure is not greater than 0.4 MPa.

[0030] Furthermore, in the mechanical ball milling described in step 6), the mechanical ball milling solvent is one of propylene glycol, diethylene glycol, anhydrous ethanol, ethylene glycol, and isopropanol.

[0031] The present invention also relates to a low-temperature sintered flaky silver powder, which is obtained by using the above method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver, and can be used for both low-temperature conductive silver paste and low-temperature sintered silver paste. The bulk density of the silver powder is 1.7-3.0 g / cm 3 , tap density 3.0-5.0g / cm 3 , particle size D 50 0.3-0.8μm, specific surface area 2.0-3.0m 2 / g. The low-temperature sintered small-flaky silver powder prepared by the present invention has good dispersibility, small flaking, good conductivity, and can be sintered at low temperature. It is suitable for both low-temperature conductive silver paste and low-temperature sintered silver paste, and can be used for low-temperature touch screen silver paste, conductive adhesive, and HJT solar cell electrode silver paste.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. The low-temperature sintered flaky silver powder of the present invention can be used for both low-temperature conductive silver paste and low-temperature sintered silver paste. The bulk density of the silver powder is 1.7-3.0 g / cm 3 , tap density 3.0-5.0g / cm 3 , particle size D 50 0.3-0.8μm, specific surface area 2.0-3.0m 2 / g. The low-temperature sintered small-flaky silver powder prepared by the present invention has good dispersibility, small flaking, good conductivity, and can be sintered at low temperature. It is suitable for both low-temperature conductive silver paste and low-temperature sintered silver paste, and can be used for low-temperature touch screen silver paste, conductive adhesive, and HJT solar cell electrode silver paste.

[0034] 2. The method of preparing low-temperature sintered flaky silver powder using monodisperse nano-silver of the present invention comprises the following steps: firstly, emulsifying the nano-silver to coat the surface of the nano-silver with fatty acids, and then lyophilizing and sieving the nano-powder particles without changing the properties of the nano-powder particles; then, ball milling the flaky silver powder that meets the requirements in a ball mill; and finally, obtaining the monodisperse flaky silver powder by filter pressing, lyophilizing and sieving. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a 20,000-fold local scanning electron microscope image of the silver powder prepared in Example 1 of the present invention;

[0036] Figure 2 This is a scanning electron microscope image at 10,000 times magnification of the silver powder prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0037] Preferred implementation cases of the present invention are further described in detail below, but the present invention is not limited to the implementation cases.

[0038] Embodiment 1:

[0039] A method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver comprises the following steps:

[0040] 1. Preparation of monodisperse small-flaky silver powder: Add 2L of anhydrous ethanol and 3L of deionized water to an emulsifying barrel to prepare solution A. Under stirring, add 2kg of nano-silver powder to solution A to make it completely dispersed; then add oleic acid with a nano-silver mass fraction of 0.5% to the emulsifying barrel and stir for 20 minutes. Take out the emulsified nano-silver and add it to a filter press. Adjust the pressure to 0.35Mpa and filter until no liquid flows out from the bottom of the filter press tank. Stop filtering and take out the nano-silver after filtering. Put it into a freeze dryer for freeze drying at a freeze drying temperature of -80°C. Take it out after 20 hours and pass it through a 100-mesh sieve.

[0041] 2. Ball milling: put 2kg of sieved nanosilver into a ball mill, add 2L of ethylene glycol, use 0.5mm zirconium oxide balls as the ball milling medium, adjust the ball mill frequency to 40Hz, and mill for 3h. Detect the particle size D 50 0.6-0.8μm, take out the ball powder together, and pass it through a 350-mesh sieve; put the filtered small flake silver powder into a filter press, adjust the pressure to 0.35Mpa, and filter until no liquid flows out from the bottom of the filter press tank, then add 2L of anhydrous ethanol for filtering, stop filtering after filtering, take out the nano silver after filtering, put it into a freeze dryer for freeze drying, the freeze drying temperature is -80℃, take it out after 20h, and pass it through a 350-mesh sieve;

[0042] The technical index of the obtained silver powder is: the bulk density of the silver powder is 2.2g / cm 3 , tap density 4.70g / cm 3 , particle size D 50 0.46μm, surface area ratio 2.66m 2 / g.

[0043] Figure 1 This is a 20,000-fold local scanning electron microscope image of the silver powder obtained in Example 1. It can be seen that the particle size of the flake powder is between 343.55nm and 643.47nm, which is in line with the product scope of our rights.

[0044] Figure 2 This is a 10,000-fold scanning electron microscope image of the silver powder obtained in Example 1. It can be seen that all the silver powder particles are ball-milled into small flakes of silver powder, meeting the product design requirements.

[0045] Embodiment 2:

[0046] A method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver comprises the following steps:

[0047] 1. Preparation of monodisperse flaky silver powder: Add 2L of anhydrous ethanol and 3L of deionized water to an emulsifying barrel to prepare solution A. Under stirring, add 2kg of nano-silver powder to solution A to make it completely dispersed; then dissolve stearic acid with a mass fraction of 0.5% of nano-silver in 50ml of anhydrous ethanol to form solution B, add solution B to the emulsifying barrel and stir for 20min, take out the emulsified nano-silver and add it to a filter press, adjust the pressure to 0.35Mpa and filter until no liquid flows out from the bottom of the filter press tank, stop filtering, take out the nano-silver after filtering, put it into a freeze dryer for freeze drying, the freeze drying temperature is -80℃, take it out after 20h, and pass it through a 100-mesh sieve;

[0048] 2. Ball milling: put 2kg of sieved nanosilver into a ball mill, add 1L of propylene glycol and 1L of anhydrous ethanol, use 0.8m zirconium oxide balls as the ball milling medium, adjust the ball mill frequency to 40Hz, and mill for 3h. Detect the particle size D 50 0.6-0.8μm, take out the ball powder together, and pass it through a 350-mesh sieve; put the filtered small flake silver powder into a filter press, adjust the pressure to 0.35Mpa, and filter until no liquid flows out from the bottom of the filter press tank, then add 2L of anhydrous ethanol for filtering, stop filtering after filtering, take out the nano silver after filtering, put it into a freeze dryer for freeze drying, the freeze drying temperature is -80℃, take it out after 20h, and pass it through a 350-mesh sieve;

[0049] The technical index of the obtained silver powder is: the bulk density of the silver powder is 2.6g / cm 3 , tap density 4.60g / cm 3 , particle size D 50 0.55μm, surface area ratio 2.2m 2 / g.

[0050] Embodiment 3:

[0051] A method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver comprises the following steps:

[0052] 1. Preparation of monodisperse flaky silver powder: Add 2L of anhydrous ethanol and 3L of deionized water to an emulsifying barrel to prepare solution A. Under stirring, add 2kg of nano-silver powder to solution A to make it completely dispersed; then add stearic acid with a nano-silver mass fraction of 0.5% to the emulsifying barrel and stir for 20 minutes. Take out the emulsified nano-silver and add it to a filter press. Adjust the pressure to 0.35Mpa and filter until no liquid flows out from the bottom of the filter press tank. Stop filtering and take out the nano-silver after filtering. Put it into a freeze dryer for freeze drying at a freeze drying temperature of -80°C. Take it out after 20 hours and pass it through a 100-mesh sieve.

[0053] 2. Ball milling: put 2kg of sieved nanosilver into a ball mill, add 1L ethylene glycol + 1L anhydrous ethanol, the ball milling medium is 0.5mm zirconia ball, adjust the ball mill frequency to 40Hz, the ball milling time is 3h, and the particle size D is tested. 50 0.6-0.8μm, take out the ball powder together, and pass it through a 350-mesh sieve; put the filtered small flake silver powder into a filter press, adjust the pressure to 0.35Mpa, and filter until no liquid flows out from the bottom of the filter press tank, then add 2L of anhydrous ethanol for filtering, stop filtering after filtering, take out the nano silver after filtering, put it into a freeze dryer for freeze drying, the freeze drying temperature is -80℃, take it out after 20h, and pass it through a 350-mesh sieve;

[0054] The technical index of the obtained silver powder is: the bulk density of the silver powder is 1.96g / cm 3 , tap density 3.70g / cm 3 , particle size D 50 0.65μm, surface area ratio 2.50m 2 / g.

[0055] Embodiment 4:

[0056] A method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver comprises the following steps:

[0057] Preparation of monodisperse small-flaky silver powder: Add 2L of anhydrous ethanol and 3L of deionized water to an emulsification barrel to prepare solution A, add 2kg of nano-silver powder to solution A under stirring to make it completely dispersed; then add oleic acid + 0.25% stearic acid with a nano-silver mass fraction of 0.25% to the emulsification barrel and stir for 20 minutes, take out the emulsified nano-silver and add it to a filter press, adjust the pressure to 0.35Mpa and filter until no liquid flows out from the bottom of the filter press tank, stop filtering, take out the nano-silver after filtering, put it into a freeze dryer for freeze drying, the freeze drying temperature is -80°C, take it out after 20 hours, and pass it through a 100-mesh sieve;

[0058] 2. Ball milling: put 2kg of sieved nanosilver into a ball mill, add 2L of anhydrous ethanol, use 0.8mm zirconium oxide balls as the ball milling medium, adjust the ball mill frequency to 40Hz, and mill for 3h. Detect the particle size D 500.3-0.8μm, take out the ball powder together, and pass it through a 350-mesh sieve; put the filtered small flake silver powder into a filter press, adjust the pressure to 0.35Mpa, and filter until no liquid flows out from the bottom of the filter press tank, then add 2L of anhydrous ethanol for filtering, stop filtering after filtering, take out the nano silver after filtering, put it into a freeze dryer for freeze drying, the freeze drying temperature is -80℃, take it out after 20h, and pass it through a 350-mesh sieve;

[0059] The technical index of the obtained silver powder is: the bulk density of the silver powder is 1.96g / cm 3 , tap density 3.50g / cm 3 , particle size D 50 0.73μm, surface area ratio 2.76m 2 / g.

[0060] Embodiment 5:

[0061] A method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver comprises the following steps:

[0062] 1. Preparation of monodisperse small-flaky silver powder: Add 2L of anhydrous ethanol and 3L of deionized water to an emulsifying barrel to prepare solution A. Under stirring, add 2kg of nano-silver powder to solution A to make it completely dispersed; then add oleic acid with a nano-silver mass fraction of 0.5% to the emulsifying barrel and stir for 20 minutes. Take out the emulsified nano-silver and add it to a filter press. Adjust the pressure to 0.35Mpa and filter until no liquid flows out from the bottom of the filter press tank. Stop filtering and take out the nano-silver after filtering. Put it into a freeze dryer for freeze drying at a freeze drying temperature of -80°C. Take it out after 20 hours and pass it through a 100-mesh sieve.

[0063] 2. Ball milling: put 2kg of sieved nanosilver into a ball mill, add 2L of ethylene glycol, use 0.8mm zirconium oxide balls as the ball milling medium, adjust the ball mill frequency to 40Hz, and mill for 3h. Detect the particle size D 50 0.6-0.8μm, take out the ball powder together, and pass it through a 350-mesh sieve; put the filtered small flake silver powder into a filter press, adjust the pressure to 0.35Mpa, and filter until no liquid flows out from the bottom of the filter press tank, then add 2L of anhydrous ethanol for filtering, stop filtering after filtering, take out the nano silver after filtering, put it into a freeze dryer for freeze drying, the freeze drying temperature is -80℃, take it out after 20h, and pass it through a 350-mesh sieve;

[0064] The technical index of the obtained silver powder is: the bulk density of the silver powder is 1.78g / cm 3 , tap density 3.30g / cm 3 , particle size D 50 0.77μm, surface area ratio 2.86m 2 / g.

[0065] Comparative Example 1

[0066] Compared with Example 1, the difference is that in Example 1, the wet silver powder is subjected to two stages of ball milling to obtain large flake silver powder D 50 >5μm, Example 1: The nano silver powder is first emulsified, freeze-dried and then ball-milled to obtain D 50 0.55μm monodisperse silver flake powder.

[0067] Comparative Example 2

[0068] Compared with Example 1, the difference is that Comparative Example 2 is to prepare the flaky overlapping silver powder by chemical reaction of two organic acids with sulfate solution, and the average particle size D 50 3.5 μm, Example 1: The nano silver powder is first emulsified, freeze-dried and then ball-milled to obtain D 50 0.55μm monodisperse silver flake powder.

[0069] Result analysis:

[0070] 1. Through Examples 1-5, it can be seen that the low-temperature sintered flaky silver powder obtained by the method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver according to the present invention can be used for both low-temperature conductive silver paste and low-temperature sintered silver paste. The bulk density of the silver powder is 1.78-2.6 g / cm 3 , tap density 3.30-4.70g / cm 3 , particle size D 50 0.46-0.77μm, surface area ratio 2.20-2.86m 2 / g.

[0071] 2. Comparison between Example 1 and Comparative Example 1 shows that different ball milling treatment methods for silver powders with different particle sizes will cause the initial product to become coarser, which in turn causes the final ball milled product to exceed a reasonable particle size range, resulting in the inability to achieve low-temperature sintering after subsequent slurry formation.

[0072] 3. Comparison between Example 1 and Comparative Example 2: The flaky overlapping silver powder prepared by chemically reacting two organic acids with a sulfate solution has an average particle size D 50 3.5μm, the size distribution of the final reaction product is uneven and the silver flakes overlap, resulting in poor dispersion of the silver powder, and the resistivity becomes larger after slurry preparation and poor printing performance.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver, characterized in that: The steps include: 1) First, add an alcohol solvent with a volume equivalent to 2 times the mass of the monodisperse nanosilver powder into a disperser, and then add the prepared monodisperse nanosilver according to the ratio of 1 kg of monodisperse nanosilver powder to 2 L of alcohol solvent, and perform emulsification treatment in the disperser for 10-20 minutes; The alcohol solvent is selected from one of glycerol, diethylene glycol, anhydrous ethanol, ethylene glycol, and isopropanol; The monodisperse nano silver powder has a particle size D 50 0.3-0.5μm, specific surface area 1.8-2.2m 2 / g; 2) dissolving a fatty acid equivalent to 0.4-0.6% of the mass of the monodisperse nano-silver powder in an alcohol solvent equivalent to 4-5 times the mass of the monodisperse nano-silver powder to completely dissolve it into solution A; The fatty acid is selected from palmitic acid, oleic acid, oleyl glyceryl, stearic acid, stearyl glyceryl, and hexadecanol; 3) Add all of solution A into the disperser in step 1), and stir thoroughly for 10-30 minutes to obtain uniformly emulsified silver powder; 4) putting the emulsified silver powder in the previous step into a filter press for filtering; 5) Place the filtered silver powder in a freeze dryer and dry it at a freezing temperature of -80°C and a drying temperature of 35°C; 6) The freeze-dried silver powder was passed through a 100-mesh sieve and directly connected to a ball mill for mechanical ball milling; 7) After ball milling, check the particle size D 50 0.6-0.8μm passed through a 350 mesh sieve to obtain low-temperature sintered small flake silver powder, which can be used for both low-temperature conductive silver paste and low-temperature sintered silver paste. The bulk density of the silver powder is 1.7-3.0g / cm 3 , tap density 3.0-5.0g / cm 3 , particle size D 50 0.3-0.8μm, specific surface area 2.0-3.0m 2 / g.

2. The method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver according to claim 1, characterized in that: In step 4), the filtration pressure is characterized in that the filtration pressure air does not contain moisture and the air pressure is not greater than 0.4 MPa.

3. The method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver according to claim 1, characterized in that: In the mechanical ball milling of step 6), the mechanical ball milling solvent is one of glycerol, diethylene glycol, anhydrous ethanol, ethylene glycol, and isopropanol.

4. A method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver, characterized in that: The method for preparing low-temperature sintered flaky silver powder using monodisperse nanosilver according to any one of claims 1 to 3 can be used for both low-temperature conductive silver paste and low-temperature sintered silver paste. The bulk density of the silver powder is 1.7-3.0 g / cm 3 , tap density 3.0-5.0g / cm 3 , particle size D 50 0.3-0.8μm, specific surface area 2.0-3.0m 2 / g.

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