A method for preparing micron-sized spherical or spheroidal Cu powder in an aqueous phase

Abstract

The application relates to a method for preparing micron-grade spherical or spheroidal Cu powder in an aqueous phase, which comprises the following steps: weighing a certain amount of copper sulfate and polydiallyldimethylammonium chloride, adding the copper sulfate and the polydiallyldimethylammonium chloride into a certain volume of water, stirring and dissolving to obtain solution A; the molar concentrations of the copper sulfate and the polydiallyldimethylammonium chloride in the solution A are 30-80 mmol / L and 100-300 mmol / L respectively; weighing a certain amount of a reducing agent N,N-diethylhydroxylamine, adding the reducing agent into a certain volume of water, stirring and dissolving to obtain solution B; mixing the solution A and the solution B, stirring at a certain rotating speed at a temperature of 70-95 DEG C for 4h; then centrifugal separation, washing and vacuum drying to obtain micron-grade Cu powder. The micron-grade Cu powder prepared by the application is spherical or spheroidal, has good dispersibility, uniform particle size distribution, adjustable particle size in the range of 1.0-5.0 mu m, narrow particle size distribution range, uniform morphology, high crystallinity, and is beneficial to further preparation of Ag-coated Cu powder (Cu@Ag).

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal powder preparation, and particularly relates to a method for preparing micron-level spherical or quasi-spherical Cu powder in an aqueous phase. BACKGROUND

[0002] Cu powder has low resistance and material cost, and has been widely studied as a filler in conductive paste in the touch panel and solar cell industries. However, pure Cu powder is easily oxidized in air at room temperature, and the oxidation process accelerates with increasing temperature. The preparation and application of Ag-coated Cu powder (Cu@Ag) can inhibit the surface oxidation of Cu powder. In advanced packaging applications, the pitch of Cu interconnection becomes narrower and narrower, so it is more important to prepare metal powder fillers (including Cu@Ag powder) with a particle size of several microns. Since traditional atomization methods cannot produce such small particles, it is more suitable to use a wet chemical method to prepare Cu powder with a particle size of several microns. The wet chemical method for preparing Cu powder can minimize the particle size difference of Cu powder and obtain Cu powder with uniform particle size.

[0003] The morphology, particle size and distribution, and dispersibility of Cu powder have an important influence on the performance of the subsequently prepared Cu@Ag powder. The Chinese invention with publication number CN 103397349 B uses copper sulfate, ammonium sulfate, ammonia, an additive, and water to form an electrolyte, and after nitrogen deoxidization, two-dimensional feather-like Cu powder is prepared on the cathode by direct current three-electrode electrolysis.

[0004] In electronic paste applications, the contact surface structure of the conductive film formed by spherical or quasi-spherical Ag powder and the conductivity of the electrode are good, and the photoelectric conversion efficiency of the prepared solar cell is high. Therefore, to prepare high-performance Cu@Ag powder, it is necessary to first prepare spherical or quasi-spherical Cu powder with uniform particle size and good dispersibility. At present, the use of a wet chemical method to prepare micron-level Cu powder has become a more critical production technology. The Chinese invention with publication number CN 114749677 A uses two dispersants (such as polyvinylpyrrolidone and beta-cyclodextrin) and two reducing agents (such as sodium hypophosphite and ascorbic acid) in a mixed solution of ethylene glycol and water to prepare Cu powder with a particle size of 1-10 μm. The disadvantage is that from the SEM image, it can be seen that the particle size distribution of some samples is wide, and some samples have agglomeration. Moreover, in a considerable part of the samples, in addition to quasi-spherical Cu powder, there are also a lot of flaky Cu powder, that is, the product morphology is not uniform. This will affect the subsequent Ag coating and the performance of the conductive paste. Therefore, it is particularly important to use a simple wet chemical method to prepare spherical or quasi-spherical Cu powder with narrow particle size range distribution, adjustable particle size, uniform morphology, and high dispersibility. SUMMARY

[0005] To solve the above problems, the application provides a method for preparing micron-sized spherical or quasi-spherical Cu powder in an aqueous phase, aiming to prepare spherical or quasi-spherical Cu powder with smooth surface, uniform particle size distribution, adjustable particle size in the range of 1.0-5.0 μm, uniform morphology and high dispersity by using a simple process.

[0006] The application is realized by the following technical scheme, a method for preparing micron-sized spherical or quasi-spherical Cu powder in an aqueous phase according to the application, comprising the following steps:

[0007] (1) A certain amount of copper sulfate and polydiallyldimethylammonium chloride (PDDA) are weighed and added to a certain volume of water, stirred until completely dissolved to obtain solution A, which is ready for use;

[0008] The molar concentration of copper sulfate in solution A is 30-80 mmol / L, and the molar concentration of PDDA (repeat unit) is 100-300 mmol / L;

[0009] (2) A certain amount of reducing agent N,N-diethylhydroxylamine (DEHA) is weighed and added to a certain volume of water, stirred until completely dissolved to obtain solution B, which is ready for use; the molar concentration of the reducing agent in the solution B is 80-120 mmol / L;

[0010] (3) After mixing solution A and solution B, stirring is carried out at a temperature of 70-95°C and a certain speed for 4 hours; then centrifugal separation is carried out, the precipitate is washed with deionized water and vacuum dried at 40°C to obtain micron-sized Cu powder.

[0011] Preferably, the volume of solvent water used in steps (1) and (2) is equal.

[0012] Preferably, the speed in step (3) is 200-800 rpm / min.

[0013] Further, the prepared Cu powder has a spherical or quasi-spherical morphology, a narrow particle size distribution range and an adjustable particle size in the range of 1.0-5.0 μm.

[0014] The application has obvious advantages and beneficial effects compared with the prior art. By the above technical scheme, the application can achieve considerable technical progress and practicality, and has wide utilization value, at least having the following advantages:

[0015] (1), The micron grade Cu powder prepared in the application is spherical or spheroid, the morphology is uniform, the Cu powder has good dispersibility, there is no other structure of Cu product, the Cu powder particle size distribution is uniform, the particle size is adjustable in the range of 1.0-5.0 mu m, the particle size distribution range is relatively narrow, the surface is smooth, the crystallinity is high, and the oxidation resistance is high, which is beneficial to further preparation of Ag coated Cu powder (Cu@Ag).

[0016] (2), The polydiallyldimethylammonium chloride is used as a dispersant in the preparation process, the polydiallyldimethylammonium chloride is used to improve the dispersibility of the product and control the morphology of the product to be spherical or spheroid structure. Water is used as a reaction solvent, the process is green and environmentally friendly, simple to realize, and easy to enlarge.

[0017] (3), The synthesis temperature is relatively low, which is mainly due to the selection and use of N,N-diethylhydroxylamine reductant. The N,N-diethylhydroxylamine reductant has moderate reducing capacity, and can synthesize Cu powder with excellent performance, narrow particle size distribution range, high dispersity, high crystallinity and uniform morphology at a relatively low temperature. By changing the concentration of reactants, reaction temperature and stirring speed, micron grade spherical or spheroid Cu powder with uniform particle size and adjustable size from 1.0 mu m to 5.0 mu m can be effectively synthesized. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The SEM image of the Cu powder prepared in example 1 of the application is enlarged 2000 times;

[0019] Figure 2 The SEM image of the Cu powder prepared in example 1 of the application is enlarged 5000 times;

[0020] Figure 3 The SEM image of the Cu powder prepared in example 2 of the application is enlarged 2000 times;

[0021] Figure 4 The SEM image of the Cu powder prepared in example 2 of the application is enlarged 5000 times;

[0022] Figure 5 The SEM image of the Cu powder prepared in example 3 of the application is enlarged 2000 times;

[0023] Figure 6 The SEM image of the Cu powder prepared in example 3 of the application is enlarged 5000 times;

[0024] Figure 7 The SEM image of the Cu powder prepared in example 4 of the application is enlarged 2000 times;

[0025] Figure 8SEM image of Cu powder prepared in Example 4 of the present application, magnified 5000 times;

[0026] Figure 9 SEM image of Cu powder prepared in Example 5 of the present application, magnified 2000 times;

[0027] Figure 10 SEM image of Cu powder prepared in Example 5 of the present application, magnified 5000 times;

[0028] Figure 11 SEM image of Cu powder prepared in Example 6 of the present application, magnified 2000 times;

[0029] Figure 12 SEM image of Cu powder prepared in Example 6 of the present application, magnified 5000 times;

[0030] Figure 13 SEM image of Cu powder prepared in Example 7 of the present application, magnified 1000 times;

[0031] Figure 14 SEM image of Cu powder prepared in Example 7 of the present application, magnified 2000 times;

[0032] Figure 15 SEM image of Cu powder prepared in Example 8 of the present application, magnified 1000 times;

[0033] Figure 16 SEM image of Cu powder prepared in Example 8 of the present application, magnified 2000 times;

[0034] Figure 17 SEM image of Cu powder prepared in Example 9 of the present application, magnified 1000 times;

[0035] Figure 18 SEM image of Cu powder prepared in Example 9 of the present application, magnified 2000 times. DETAILED DESCRIPTION

[0036] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be described below in connection with specific embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0037] Example 1:

[0038] 1) Weigh a certain mass of copper sulfate and polydiallyldimethylammonium chloride (PDDA) respectively, add to 50 mL of water, stir until completely dissolved, so that the concentration of copper sulfate and PDDA is 70 mmol / L and 150 mmol / L respectively, to obtain solution A, ready for use;

[0039] 2) Weigh a certain mass of reducing agent N, N-diethylhydroxylamine (DEHA), add to 50 mL of water, completely dissolved, so that the concentration of DEHA is 100 mmol / L, to obtain solution B, ready for use;

[0040] 3) Add solution A and solution B to a 200 mL three-necked round-bottom flask in turn, stir at 80℃ and 300 rpm / min for 4 h;

[0041] 4) Centrifuge the product after step 3), wash the precipitate with deionized water, and vacuum dry at 40℃ to obtain spherical or spherical-like Cu powder with an average particle size of about 3.0 μm. The SEM images of the Cu powder at different magnifications are shown in Figure 1 and Figure 2 .

[0042] Example 2:

[0043] 1) Weigh a certain mass of copper sulfate and PDDA respectively, add to 50 mL of water, stir until completely dissolved, so that the concentration of copper sulfate and PDDA is 70 mmol / L and 180 mmol / L respectively, to obtain solution A, ready for use;

[0044] 2) Weigh a certain mass of reducing agent DEHA, add to 50 mL of water, completely dissolved, so that the concentration is 100 mmol / L, to obtain solution B, ready for use;

[0045] 3) Add solution A and solution B to a 200 mL three-necked round-bottom flask in turn, stir at 80℃ and 400 rpm / min for 4 h;

[0046] 4) Centrifuge the product after step 3), wash the precipitate with deionized water, and vacuum dry at 40℃ to obtain spherical or spherical-like Cu powder with an average particle size of about 2.6 μm. The SEM images of the Cu powder at different magnifications are shown in Figure 3 and Figure 4 .

[0047] Example 3:

[0048] 1) Take a certain mass of copper sulfate and PDDA respectively, add to 50 mL of water, stir until completely dissolved, so that the concentration of copper sulfate and PDDA is 65 mmol / L and 200 mmol / L respectively, to obtain solution A, ready for use;

[0049] 2) Take a certain mass of reducing agent DEHA, add to 50 mL of water, completely dissolved, so that its concentration is 100 mmol / L, to obtain solution B, ready for use;

[0050] 3) Solution A and solution B are added to a 200 mL three-necked round-bottom flask in turn, stirred at 85°C and 600 rpm / min for 4h;

[0051] 4) The product after step 3) is centrifuged, the precipitate is washed with deionized water and vacuum dried at 40°C to obtain spherical or spherical Cu powder with an average particle size of about 2.4 μm. The SEM images of the Cu powder with different magnifications are shown in Figure 5 and Figure 6 .

[0052] Example 4:

[0053] 1) Take a certain mass of copper sulfate and PDDA respectively, add to 50 mL of water, stir until completely dissolved, so that the concentration of copper sulfate and PDDA is 50 mmol / L and 200 mmol / L respectively, to obtain solution A, ready for use;

[0054] 2) Take a certain mass of reducing agent DEHA, add to 50 mL of water, completely dissolved, so that its concentration is 110 mmol / L, to obtain solution B, ready for use;

[0055] 3) Solution A and solution B are added to a 200 mL three-necked round-bottom flask in turn, stirred at 85°C and 600 rpm / min for 4h;

[0056] 4) The product after step 3) is centrifuged, the precipitate is washed with deionized water and vacuum dried at 40°C to obtain spherical or spherical Cu powder with an average particle size of about 1.8 μm. The SEM images of the Cu powder with different magnifications are shown in Figure 7 and Figure 8 .

[0057] Example 5:

[0058] 1) Take a certain mass of copper sulfate and PDDA respectively, add to 50 mL of water, stir until completely dissolved, so that the concentration of copper sulfate and PDDA is 40 mmol / L and 260 mmol / L respectively, to obtain solution A, ready for use;

[0059] 2) Weigh a certain amount of reducing agent DEHA into 50 mL of water, completely dissolve it, and then make its concentration 110 mmol / L to obtain solution B, which is ready for use;

[0060] 3) Add solution A and solution B into a 200 mL three-necked round-bottom flask in sequence, and then stir and react at 85°C and 650 rpm / min for 4 h;

[0061] 4) Centrifugalize the product after the reaction in step 3), wash the precipitate with deionized water, and then vacuum dry it at 40°C to obtain spherical or spherical-like Cu powder, which has an average particle size of about 1.3 μm, is uniform in particle size and good in dispersibility, and has SEM images of different magnifications as shown in Figure 9 and Figure 10 .

[0062] Example 6:

[0063] 1) Weigh a certain amount of copper sulfate and PDDA into 50 mL of water respectively, and then stir until they are completely dissolved to make the concentrations of copper sulfate and PDDA 30 mmol / L and 300 mmol / L respectively to obtain solution A, which is ready for use;

[0064] 2) Weigh a certain amount of reducing agent DEHA into 50 mL of water, completely dissolve it, and then make its concentration 120 mmol / L to obtain solution B, which is ready for use;

[0065] 3) Add solution A and solution B into a 200 mL three-necked round-bottom flask in sequence, and then stir and react at 95°C and 800 rpm / min for 4 h;

[0066] 4) Centrifugalize the product after the reaction in step 3), wash the precipitate with deionized water, and then vacuum dry it at 40°C to obtain spherical or spherical-like Cu powder, which has an average particle size of about 1.0 μm, is uniform in particle size and good in dispersibility, and has SEM images of different magnifications as shown in Figure 11 and Figure 12 .

[0067] Example 7:

[0068] 1) Weigh a certain amount of copper sulfate and PDDA into 50 mL of water respectively, and then stir until they are completely dissolved to make the concentrations of copper sulfate and PDDA 70 mmol / L and 120 mmol / L respectively to obtain solution A, which is ready for use;

[0069] 2) Weigh a certain amount of reducing agent DEHA into 50 mL of water, completely dissolve it, and then make its concentration 100 mmol / L to obtain solution B, which is ready for use;

[0070] 3) Solution A and solution B were added into a 200 mL three-necked round bottom flask in turn, and stirred at 80°C and 400 rpm / min for 4h;

[0071] 4) The product after step 3) was centrifuged, and the precipitate was washed with deionized water and dried at 40°C under vacuum to obtain spherical or spherical-like Cu powder with an average particle size of about 3.5 μm. The SEM images of the Cu powder with different magnifications are shown in Figure 13 and Figure 14 .

[0072] Example 8:

[0073] 1) A certain amount of copper sulfate and PDDA were weighed and added into 50 mL water, and stirred until completely dissolved to obtain solution A, with the concentration of copper sulfate and PDDA being 75 mmol / L and 100 mmol / L respectively, for standby use;

[0074] 2) A certain amount of reducing agent DEHA was weighed and added into 50 mL water, and completely dissolved to obtain solution B with a concentration of 80 mmol / L, for standby use;

[0075] 3) Solution A and solution B were added into a 200 mL three-necked round bottom flask in turn, and stirred at 75°C and 300 rpm / min for 4h;

[0076] 4) The product after step 3) was centrifuged, and the precipitate was washed with deionized water and dried at 40°C under vacuum to obtain spherical or spherical-like Cu powder with an average particle size of about 4.2 μm. The SEM images of the Cu powder with different magnifications are shown in Figure 15 and Figure 16 .

[0077] Example 9:

[0078] 1) A certain amount of copper sulfate and PDDA were weighed and added into 50 mL water, and stirred until completely dissolved to obtain solution A, with the concentration of copper sulfate and PDDA being 80 mmol / L and 100 mmol / L respectively, for standby use;

[0079] 2) A certain amount of reducing agent DEHA was weighed and added into 50 mL water, and completely dissolved to obtain solution B with a concentration of 80 mmol / L, for standby use;

[0080] 3) Solution A and solution B were added into a 200 mL three-necked round bottom flask in turn, and stirred at 70°C and 200 rpm / min for 4h;

[0081] 4) The product after the reaction of step 3) is centrifuged, the precipitate is washed with deionized water and vacuum dried at 40°C to obtain spherical or spherical-like Cu powder with an average particle size of about 5.0 μm. The Cu powder has uniform particle size and good dispersibility, and SEM images of different magnifications thereof are shown in Figs. 1-3. Figure 17 and Figure 18 as shown.

[0082] The above description is only an embodiment of the present application and does not limit the present application in any form. The present application can have other forms of embodiments according to the above structure and function, and the above embodiments are not listed one by one. Therefore, any skilled person in the art, without departing from the technical solution range of the present application, according to the technical essence of the present application, any simple modification, equivalent change and modification of the above embodiments, still belongs to the range of the technical solution of the present application.

Claims

1. A method for producing micron-sized spherical or spheroidal Cu powder in an aqueous phase, characterized by The method comprises the following steps: (1) a certain amount of copper sulfate and polydiallyldimethylammonium chloride are weighed and added into a certain volume of water, and stirred until completely dissolved to obtain solution A, which is prepared for use; The molar concentration of copper sulfate in solution A is 30-80 mmol / L, and the molar concentration of polydiallyldimethylammonium chloride is 100-300 mmol / L; (2) a certain amount of reducing agent N,N-diethylhydroxylamine is weighed and added into a certain volume of water, and stirred until completely dissolved to obtain solution B, which is prepared for use; the concentration of N,N-diethylhydroxylamine in solution B is 80-120 mmol / L, and the volumes of the solvent water used in steps (1) and (2) are equal; (3) after mixing solution A and solution B, stirring is carried out at a temperature of 70-95 DEG C and a certain rotating speed for 4 hours; then centrifugal separation is carried out, the precipitate is washed with deionized water, and vacuum drying is carried out at 40 DEG C to obtain micron-sized spherical or spherical-like Cu powder, and the particle size of the Cu powder can be controlled within 1.0-5.0 microns.

2. The method of claim 1, wherein the water phase is prepared by mixing CuSO4.5H2O, Na2S2O3.5H2O, and Na2S in distilled water. The rotating speed in step (3) is 200-800 rpm / min.

3. The method of claim 1, wherein the water phase is prepared by mixing CuSO4.5H2O, Na2S2O3.5H2O, and Na2S in distilled water. The particle size of the Cu powder is controlled by changing the concentration of the reactants, the reaction temperature and the stirring speed.

Images