Conductive nickel powder, preparation method and electronic product

Abstract

The invention discloses conductive nickel powder, a preparation method and an electronic product, relates to the technical field of conductive materials, and aims to improve the conductivity of nickel powder while giving consideration to the electromagnetic shielding function of the conductive nickel powder. According to the preparation method, the nickel powder coating the surface of the carbon nano tube is prepared, so that the prepared nickel powder is easier to break through the infiltration phenomenon, and in order to further improve the application performance of the conductive nickel powder, a polyaniline chain segment introduced with a camphorsulfonic acid structure is further prepared and formed on the surface of the nickel powder; the conductivity of a polyaniline structure is improved, the surface polarity of the nickel powder is improved, and the compatibility with resin is improved; finally, the conductive nickel powder can have high dispersity and high compatibility while having high conductivity in the conductive adhesive, and the use performance of the conductive nickel powder is improved.

Description

Technical Field

[0001] The present application relates to the technical field of conductive materials, and in particular to a conductive nickel powder, a preparation method and an electronic product. Background Art

[0002] With the rapid development of science and technology and the electronics industry, electronic devices are becoming increasingly widespread. Consequently, the technologies used in various electronic products, such as electronic components and conductive pastes, have also advanced significantly. However, this widespread adoption of electronic products has also led to the emergence of electromagnetic radiation and electromagnetic interference (EMI). Electromagnetic radiation interference (EMR) is a phenomenon in which electronic products, when in operation, generate electromagnetic waves due to charge movement or alternating electric fields. When the electromagnetic radiation reaches a certain intensity, it can seriously affect the operation of surrounding electronic products.

[0003] Currently, in the field of electromagnetic shielding, the transition metal nickel has become a commonly used metal material due to its good conductivity, antioxidant, corrosion resistance and reasonable price. However, during the preparation process, the existing conductive nickel powder has a large porosity and a small contact area between the powder particles. When it is used in conductive adhesives, it often results in poor conductivity, which seriously limits the use conditions of the conductive nickel powder. Summary of the Invention

[0004] The purpose of this application is to provide a conductive nickel powder, a preparation method and an electronic product to solve the problems raised in the prior art.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] A method for preparing conductive nickel powder comprises the following steps:

[0007] S1. The acid-treated carbon nanotubes were immersed in palladium chloride and tin chloride solutions, respectively, and subjected to ultrasonic dispersion sensitization. The carbon nanotubes were then placed in a nickel plating solution and immersed under negative pressure. The carbon nanotubes were separated by centrifugation, heated and calcined under a hydrogen atmosphere, and then cooled to room temperature to obtain nickel-plated carbon nanotubes.

[0008] S2. Add nickel-plated carbon nanotubes to deionized water, ultrasonically vibrate, add n-butanol and a surfactant, stir until uniform, add nickel nitrate, and ultrasonically disperse to obtain a reaction solution, to which hydrazine hydrate is added until the pH value of the system is 10-10.5. After heating, the reaction is allowed to stand at a constant temperature. Heating is stopped, centrifuged, and the supernatant is removed. The remaining bottom mixed solution is freeze-dried, washed with anhydrous ethanol and deionized water, and freeze-dried to obtain a primary nickel powder;

[0009] S3. Primary nickel powder, xylene, and aniline are mixed, deionized water and camphorsulfonic acid are added thereto, the mixture is stirred and mixed, ultrasonically dispersed and emulsified, the reaction system is cooled, and the mixture is added dropwise to an ammonium persulfate solution. After the reaction, the precipitate is separated by centrifugation, washed with anhydrous ethanol, anhydrous acetone, and deionized water, respectively, and vacuum dried to constant weight to obtain the conductive nickel powder.

[0010] Furthermore, in S1, the method for preparing the acid-treated carbon nanotubes is:

[0011] The carbon nanotubes were placed in a muffle furnace, heated to 450-480°C under inert gas protection, and calcined for 10-15 minutes. After cooling to room temperature, they were placed in a 1:1 mixture of concentrated nitric acid and concentrated sulfuric acid, heated to 55-70°C, and subjected to ultrasonic oscillation dispersion treatment for 2-5 hours. The mixture was then centrifuged, washed with deionized water until neutral, and dried to constant weight to obtain acid-treated carbon nanotubes.

[0012] Furthermore, in S1, the concentration of the palladium chloride solution is 0.1-0.15M, and the concentration of the tin chloride solution is 0.1-0.15M; the time of the ultrasonic dispersion sensitization treatment is 15-30 minutes, the negative pressure immersion time is 10-20 minutes, the temperature is raised to 400-450°C, and the calcination time is 30-60 minutes.

[0013] Furthermore, in S1, the nickel plating solution contains 35-60 g / L of nickel sulfate, 10-15 g / L of ammonium chloride, 10-15 g / L of sodium citrate, 5-10 g / L of sodium phosphite, and the balance is water.

[0014] Furthermore, in S2, the reaction solution includes, by weight, 100 parts of deionized water, 0.08-0.15 parts of nickel-plated carbon nanotubes, 1.5-2.5 parts of n-butanol, 5-8 parts of a surfactant, and 1.5-2.5 parts of nickel nitrate.

[0015] Furthermore, in S2, the surfactant is cetyltrimethylammonium bromide; the ultrasonic oscillation dispersion time is 8-12 hours, the temperature is raised to 60-70° C., and the constant temperature static reaction time is 4-8 hours.

[0016] Furthermore, in S3, the mixed solution includes, by weight, 1.5-5 parts of primary nickel powder, 10-15 parts of xylene, 0.45-1.5 parts of aniline, 100 parts of deionized water and 4-5 parts of camphorsulfonic acid; the ammonium persulfate solution contains 0.6-2 parts of ammonium persulfate; the ultrasonic dispersion time is 15-30 minutes, the mixture is cooled to 0-4°C, the temperature of the ammonium persulfate solution is 2-4°C, and the reaction time is 3-8 hours.

[0017] The present application also provides a conductive nickel powder, which is prepared using the above-mentioned preparation method.

[0018] The present application also provides an electronic product, comprising the above-mentioned conductive nickel powder.

[0019] Furthermore, the conductive nickel powder in the electronic product exists in the form of a conductive component in the conductive adhesive.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] In order to improve the conductive properties of nickel powder while taking into account the electromagnetic shielding function of conductive nickel powder, this application first prepared nickel-plated carbon nanotubes. After the carbon nanotubes were surface treated with concentrated sulfuric acid and concentrated nitric acid to generate active groups, their surfaces were sensitized again with tin chloride and palladium chloride. After being soaked in a nickel salt solution, they were calcined in a reducing atmosphere to prepare carbon nanotubes with nickel plating on the surface.

[0022] The present application uses deionized water, n-butanol, surfactant, nickel nitrate to form a liquid crystal structure soft template, in which the surfactant is cetyl trimethyl ammonium bromide, which is a cationic surfactant. It has a hydrophilic segment and a hydrophobic segment, and the hydrophobic segment will spontaneously aggregate and wrap self-assembly to form a micellar structure. N-butanol also has a surfactant effect, but its segment is much smaller than cetyl trimethyl ammonium bromide, so after mixing n-butanol with cetyl trimethyl ammonium bromide, the micellar structure curvature formed by the surfactant can be effectively reduced. And when n-butanol and cetyl trimethyl ammonium bromide form micelles in the water body, small cavities are formed one by one. Therefore, when hydrazine hydrate reduces nickel metal, the water body will be separated by colloidal cavitations, so that the prepared primary nickel powder will also generate small gaps formed by colloidal cavitations, effectively increasing the specific surface area of the primary nickel powder, facilitating the multiple reflection absorption of electromagnetic waves, and being conducive to absorbing electromagnetic waves and converting them, realizing the improvement of electromagnetic shielding effectiveness.

[0023] In order to further improve the application performance of primary nickel powder, the present application also modifies the prepared primary nickel powder; after mixing the primary nickel powder with toluene and aniline, it is again mixed with deionized water and camphorsulfonic acid to form an emulsion, in which the camphorsulfonic acid itself can act as an acid provider and a surfactant; and under the action of an initiator, it can form polyaniline chain segments on the surface of the primary nickel powder together with aniline, thereby improving the polarity of the surface of the primary nickel powder and improving the compatibility of the primary nickel powder with the resin matrix. Due to the introduction of camphorsulfonic acid structure in the chain segment, the sulfonic acid group therein can undergo protonation reaction with the imine group in polyaniline, thereby forming polarons and improving the conductive properties of the polyaniline structure; and due to the joint participation of polyaniline and carbon nanotubes, the conductive nickel powder prepared in the present application can ultimately have high conductivity while having high dispersibility and high compatibility, thereby improving its performance in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of the process for preparing nickel-plated carbon nanotubes in Example 1 of the present application;

[0025] Figure 2 This is a flow chart of the process for preparing conductive nickel powder in Example 1 of the present application;

[0026] Figure 3 is the synthetic structural formula of polyaniline on the surface of nickel powder in Example 1 of the present application;

[0027] Figure 4 SEM characterization image of the conductive nickel powder prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0029] The carbon nanotubes used in the examples and comparative examples of the present application are commercially available carbon nanotubes with product number 100253, a purity of ≥95%, a length of 10-30 μm, and a diameter of 10-20 nm.

[0030] Example 1

[0031] like Figure 1 and Figure 2 As shown, a method for preparing conductive nickel powder comprises the following steps:

[0032] S1. The acid-treated carbon nanotubes were immersed in a 0.1M palladium chloride solution and a 0.1M tin chloride solution, respectively. After ultrasonic dispersion sensitization for 15 minutes, they were placed in a nickel plating solution and vacuumed to 2×10 -2 Pa, after negative pressure immersion for 15 min, the carbon nanotubes were separated by centrifugation, heated to 400 ° C, calcined under hydrogen atmosphere for 30 min, and cooled to room temperature to obtain nickel-plated carbon nanotubes;

[0033] Wherein, the preparation method of the acid-treated carbon nanotubes is:

[0034] The carbon nanotubes were placed in a muffle furnace, heated to 450°C under inert gas protection, and calcined for 10 minutes. After cooling to room temperature, they were placed in a 1:1 mixture of concentrated nitric acid and concentrated sulfuric acid, heated to 60°C, and subjected to ultrasonic oscillation dispersion treatment for 4 hours. The mixture was then centrifuged, washed with deionized water until neutral, and dried to constant weight to obtain acid-treated carbon nanotubes.

[0035] The nickel plating solution is composed of 35g / L nickel sulfate, 10g / L ammonium chloride, 10g / L sodium citrate, 5g / L sodium phosphite and the balance deionized water;

[0036] S2. Add nickel-plated carbon nanotubes to deionized water and disperse them under ultrasonic oscillation for 8 hours. Then, add n-butanol and cetyltrimethylammonium bromide and mix them. After stirring until uniform, add nickel nitrate and disperse them under ultrasonic oscillation to obtain a reaction solution. Hydrazine hydrate is added to the solution until the pH of the system is 10. The solution is heated to 65°C and allowed to react at this temperature for 6 hours. The solution is then heated and centrifuged. The supernatant is removed and the remaining bottom mixture is lyophilized. The mixture is then washed three times with anhydrous ethanol and three times with deionized water, and then lyophilized again to obtain a primary nickel powder.

[0037] Wherein, the reaction solution comprises, by weight, 100 parts of deionized water, 0.1 parts of nickel-plated carbon nanotubes, 1.5 parts of n-butanol, 5 parts of hexadecyltrimethylammonium bromide and 1.5 parts of nickel nitrate;

[0038] S3. By weight, 2 parts of primary nickel powder, 10 parts of xylene, and 0.5 parts of aniline were mixed, 100 parts of deionized water and 4 parts of camphorsulfonic acid were added thereto, and the mixture was stirred and mixed. After ultrasonic dispersion for 15 minutes, the reaction system was cooled to 4°C, and the mixture was added dropwise to an ammonium persulfate solution containing 0.6 parts of ammonium persulfate at a temperature of 2°C. After reacting for 5 hours, the mixture was centrifuged and precipitated, and then washed three times with anhydrous ethanol, anhydrous acetone, and deionized water, respectively, and then vacuum dried to constant weight to obtain the conductive nickel powder. The SEM characterization image of the conductive nickel powder is shown as follows. Figure 4 shown.

[0039] Example 2

[0040] A method for preparing conductive nickel powder comprises the following steps:

[0041] Compared with Example 1, this embodiment increases the nickel ion concentration in the nickel plating solution in step S1;

[0042] S1. The acid-treated carbon nanotubes were immersed in a 0.1M palladium chloride solution and a 0.1M tin chloride solution, respectively. After ultrasonic dispersion sensitization for 15 minutes, they were placed in a nickel plating solution and vacuumed to 2×10 -2 Pa, after negative pressure immersion for 15 min, the carbon nanotubes were separated by centrifugation, heated to 450 ° C, calcined under hydrogen atmosphere for 30 min, and cooled to room temperature to obtain nickel-plated carbon nanotubes;

[0043] Wherein, the preparation method of the acid-treated carbon nanotubes is:

[0044] The carbon nanotubes were placed in a muffle furnace, heated to 450°C under inert gas protection, and calcined for 10 minutes. After cooling to room temperature, they were placed in a 1:1 mixture of concentrated nitric acid and concentrated sulfuric acid, heated to 60°C, and subjected to ultrasonic oscillation dispersion treatment for 4 hours. The mixture was then centrifuged, washed with deionized water until neutral, and dried to constant weight to obtain acid-treated carbon nanotubes.

[0045] The nickel plating solution is composed of 60g / L nickel sulfate, 10g / L ammonium chloride, 10g / L sodium citrate, 5g / L sodium phosphite and the balance deionized water;

[0046] S2. Add nickel-plated carbon nanotubes to deionized water and disperse them under ultrasonic oscillation for 8 hours. Then, add n-butanol and cetyltrimethylammonium bromide and mix them. After stirring until uniform, add nickel nitrate and disperse them under ultrasonic oscillation to obtain a reaction solution. Hydrazine hydrate is added to the solution until the pH of the system is 10. The solution is heated to 65°C and allowed to react at this temperature for 6 hours. The solution is then heated and centrifuged. The supernatant is removed and the remaining bottom mixture is lyophilized. The mixture is then washed three times with anhydrous ethanol and three times with deionized water, and then lyophilized again to obtain a primary nickel powder.

[0047] Wherein, the reaction solution comprises, by weight, 100 parts of deionized water, 0.1 parts of nickel-plated carbon nanotubes, 1.5 parts of n-butanol, 5 parts of hexadecyltrimethylammonium bromide and 1.5 parts of nickel nitrate;

[0048] S3. In parts by weight, 2 parts of primary nickel powder, 10 parts of xylene, and 0.5 parts of aniline were mixed, 100 parts of deionized water and 4 parts of camphorsulfonic acid were added thereto, the mixture was stirred and mixed, and ultrasonic dispersion was performed for 15 minutes to emulsify. The reaction system was cooled to 0°C, and the mixture was added dropwise to an ammonium persulfate solution containing 0.6 parts of ammonium persulfate at a temperature of 4°C. After reacting for 5 hours, the mixture was centrifuged and precipitated, and then washed three times with anhydrous ethanol, anhydrous acetone, and deionized water, respectively, and then vacuum dried to constant weight to obtain the conductive nickel powder.

[0049] Example 3

[0050] A method for preparing conductive nickel powder comprises the following steps:

[0051] Compared with Example 2, this embodiment increases the amount of nickel-plated carbon nanotubes added in step S2;

[0052] S1. Acid-treated carbon nanotubes were immersed in a 0.1M palladium chloride solution and a 0.1M tin chloride solution, respectively. After ultrasonic dispersion sensitization for 15 minutes, the carbon nanotubes were placed in a nickel plating solution, evacuated to 2×10-2 Pa, and immersed under negative pressure for 15 minutes. The carbon nanotubes were then separated by centrifugation, heated to 400°C, calcined under a hydrogen atmosphere for 30 minutes, and cooled to room temperature to obtain nickel-plated carbon nanotubes.

[0053] Wherein, the preparation method of the acid-treated carbon nanotubes is:

[0054] The carbon nanotubes were placed in a muffle furnace, heated to 450°C under inert gas protection, and calcined for 10 minutes. After cooling to room temperature, they were placed in a 1:1 mixture of concentrated nitric acid and concentrated sulfuric acid, heated to 60°C, and subjected to ultrasonic oscillation dispersion treatment for 4 hours. The mixture was then centrifuged, washed with deionized water until neutral, and dried to constant weight to obtain acid-treated carbon nanotubes.

[0055] The nickel plating solution is composed of 60g / L nickel sulfate, 10g / L ammonium chloride, 10g / L sodium citrate, 5g / L sodium phosphite and the balance deionized water;

[0056] S2. Add nickel-plated carbon nanotubes to deionized water and disperse them under ultrasonic oscillation for 8 hours. Then, add n-butanol and cetyltrimethylammonium bromide and mix them. After stirring until uniform, add nickel nitrate and disperse them under ultrasonic oscillation to obtain a reaction solution. Hydrazine hydrate is added to the solution until the pH of the system is 10. The solution is heated to 65°C and allowed to react at this temperature for 6 hours. The solution is then heated and centrifuged. The supernatant is removed and the remaining bottom mixture is lyophilized. The mixture is then washed three times with anhydrous ethanol and three times with deionized water, and then lyophilized again to obtain a primary nickel powder.

[0057] Wherein, the reaction solution comprises, by weight, 100 parts of deionized water, 0.15 parts of nickel-plated carbon nanotubes, 1.5 parts of n-butanol, 5 parts of hexadecyltrimethylammonium bromide and 1.5 parts of nickel nitrate;

[0058] S3. In parts by weight, 2 parts of primary nickel powder, 10 parts of xylene, and 0.5 parts of aniline were mixed, 100 parts of deionized water and 4 parts of camphorsulfonic acid were added thereto, and the mixture was stirred and mixed. After ultrasonic dispersion for 15 minutes to emulsify, the reaction system was cooled to 2°C, and the mixture was added dropwise to an ammonium persulfate solution containing 0.6 parts of ammonium persulfate at a temperature of 3°C. After reacting for 5 hours, the mixture was centrifuged and precipitated, and then washed three times with anhydrous ethanol, anhydrous acetone, and deionized water, respectively, and then vacuum dried to constant weight to obtain the conductive nickel powder.

[0059] Example 4

[0060] A method for preparing conductive nickel powder comprises the following steps:

[0061] Compared with Example 3, this embodiment increases the amount of primary nickel powder added in step S3;

[0062] S1. The acid-treated carbon nanotubes were immersed in a 0.1M palladium chloride solution and a 0.1M tin chloride solution, respectively. After ultrasonic dispersion sensitization for 15 minutes, they were placed in a nickel plating solution and vacuumed to 2×10 -2 Pa, after negative pressure immersion for 15 min, the carbon nanotubes were separated by centrifugation, heated to 450 ° C, calcined under hydrogen atmosphere for 30 min, and cooled to room temperature to obtain nickel-plated carbon nanotubes;

[0063] Wherein, the preparation method of the acid-treated carbon nanotubes is:

[0064] The carbon nanotubes were placed in a muffle furnace, heated to 450°C under inert gas protection, and calcined for 10 minutes. After cooling to room temperature, they were placed in a 1:1 mixture of concentrated nitric acid and concentrated sulfuric acid, heated to 60°C, and subjected to ultrasonic oscillation dispersion treatment for 4 hours. The mixture was then centrifuged, washed with deionized water until neutral, and dried to constant weight to obtain acid-treated carbon nanotubes.

[0065] The nickel plating solution is composed of 60g / L nickel sulfate, 10g / L ammonium chloride, 10g / L sodium citrate, 5g / L sodium phosphite and the balance deionized water;

[0066] S2. Add nickel-plated carbon nanotubes to deionized water and disperse them under ultrasonic oscillation for 8 hours. Then, add n-butanol and cetyltrimethylammonium bromide and mix them. After stirring until uniform, add nickel nitrate and disperse them under ultrasonic oscillation to obtain a reaction solution. Hydrazine hydrate is added to the solution until the pH of the system is 10. The solution is heated to 65°C and allowed to react at this temperature for 6 hours. The solution is then heated and centrifuged. The supernatant is removed and the remaining bottom mixture is lyophilized. The mixture is then washed three times with anhydrous ethanol and three times with deionized water, and then lyophilized again to obtain a primary nickel powder.

[0067] Wherein, the reaction solution comprises, by weight, 100 parts of deionized water, 0.15 parts of nickel-plated carbon nanotubes, 1.5 parts of n-butanol, 5 parts of hexadecyltrimethylammonium bromide and 1.5 parts of nickel nitrate;

[0068] S3. In parts by weight, 5 parts of primary nickel powder, 10 parts of xylene, and 0.5 parts of aniline were mixed, 100 parts of deionized water and 4 parts of camphorsulfonic acid were added thereto, the mixture was stirred and mixed, and ultrasonic dispersion was performed for 15 minutes to emulsify. The reaction system was cooled to 4°C, and the mixture was added dropwise to an ammonium persulfate solution containing 0.6 parts of ammonium persulfate at a temperature of 4°C. After reacting for 5 hours, the mixture was centrifuged and precipitated, and then washed three times with anhydrous ethanol, anhydrous acetone, and deionized water, respectively, and then vacuum dried to constant weight to obtain the conductive nickel powder.

[0069] Example 5

[0070] A method for preparing conductive nickel powder comprises the following steps:

[0071] Compared with Example 3, this example increases the amount of aniline added in step S3;

[0072] S1. The acid-treated carbon nanotubes were immersed in a 0.1M palladium chloride solution and a 0.1M tin chloride solution, respectively. After ultrasonic dispersion sensitization for 15 minutes, they were placed in a nickel plating solution and vacuumed to 2×10 -2 Pa, after negative pressure immersion for 15 min, the carbon nanotubes were separated by centrifugation, heated to 400 ° C, calcined under hydrogen atmosphere for 30 min, and cooled to room temperature to obtain nickel-plated carbon nanotubes;

[0073] Wherein, the preparation method of the acid-treated carbon nanotubes is:

[0074] The carbon nanotubes were placed in a muffle furnace, heated to 450°C under inert gas protection, and calcined for 10 minutes. After cooling to room temperature, they were placed in a 1:1 mixture of concentrated nitric acid and concentrated sulfuric acid, heated to 60°C, and subjected to ultrasonic oscillation dispersion treatment for 4 hours. The mixture was then centrifuged, washed with deionized water until neutral, and dried to constant weight to obtain acid-treated carbon nanotubes.

[0075] The nickel plating solution is composed of 60g / L nickel sulfate, 10g / L ammonium chloride, 10g / L sodium citrate, 5g / L sodium phosphite and the balance deionized water;

[0076] S2. Add nickel-plated carbon nanotubes to deionized water and disperse them under ultrasonic oscillation for 8 hours. Then, add n-butanol and cetyltrimethylammonium bromide and mix them. After stirring until uniform, add nickel nitrate and disperse them under ultrasonic oscillation to obtain a reaction solution. Hydrazine hydrate is added to the solution until the pH of the system is 10. The solution is heated to 65°C and allowed to react at this temperature for 6 hours. The solution is then heated and centrifuged. The supernatant is removed and the remaining bottom mixture is lyophilized. The mixture is then washed three times with anhydrous ethanol and three times with deionized water, and then lyophilized again to obtain a primary nickel powder.

[0077] Wherein, the reaction solution comprises, by weight, 100 parts of deionized water, 0.15 parts of nickel-plated carbon nanotubes, 1.5 parts of n-butanol, 5 parts of hexadecyltrimethylammonium bromide and 1.5 parts of nickel nitrate;

[0078] S3. In parts by weight, 2 parts of primary nickel powder, 10 parts of xylene, and 0.5 parts of aniline were mixed, 100 parts of deionized water and 4 parts of camphorsulfonic acid were added thereto, the mixture was stirred and mixed, and ultrasonic dispersion was performed for 15 minutes to emulsify. The reaction system was cooled to 4°C, and the mixture was added dropwise to an ammonium persulfate solution containing 0.6 parts of ammonium persulfate at a temperature of 2°C. After reacting for 5 hours, the mixture was centrifuged and precipitated, and then washed three times with anhydrous ethanol, anhydrous acetone, and deionized water, respectively, and then vacuum dried to constant weight to obtain the conductive nickel powder.

[0079] Comparative Example 1

[0080] A method for preparing conductive nickel powder comprises the following steps:

[0081] Compared with Example 1, this comparative example did not prepare and add nickel-plated carbon nanotubes;

[0082] S1. n-Butanol and cetyltrimethylammonium bromide were added to deionized water and stirred until uniform. Nickel nitrate was then added and ultrasonically dispersed to obtain a reaction solution. Hydrazine hydrate was added to the solution until the pH of the solution reached 10. The solution was heated to 65°C and allowed to react at this temperature for 6 hours. The solution was then heated and centrifuged. The supernatant was removed and the remaining bottom mixture was lyophilized. The solution was then washed three times with anhydrous ethanol and three times with deionized water, and then lyophilized again to obtain a primary nickel powder.

[0083] Wherein, the reaction solution comprises, by weight, 100 parts of deionized water, 1.5 parts of n-butanol, 5 parts of hexadecyltrimethylammonium bromide and 1.5 parts of nickel nitrate;

[0084] S2. In parts by weight, 2 parts of primary nickel powder, 10 parts of xylene, and 0.5 parts of aniline were mixed, 100 parts of deionized water and 4 parts of camphorsulfonic acid were added thereto, the mixture was stirred and mixed, and ultrasonic dispersion was performed for 15 minutes to emulsify. The reaction system was cooled to 4°C, and the mixture was added dropwise to an ammonium persulfate solution containing 0.6 parts of ammonium persulfate at a temperature of 2°C. After reacting for 5 hours, the mixture was centrifuged and precipitated, and then washed three times with anhydrous ethanol, anhydrous acetone, and deionized water, respectively, and then vacuum dried to constant weight to obtain the conductive nickel powder.

[0085] Comparative Example 2

[0086] A method for preparing conductive nickel powder comprises the following steps:

[0087] Compared with Example 1, n-butanol and cetyltrimethylammonium bromide were not used in step S2 of this comparative example;

[0088] S1. The acid-treated carbon nanotubes were immersed in a 0.1M palladium chloride solution and a 0.1M tin chloride solution, respectively. After ultrasonic dispersion sensitization for 15 minutes, they were placed in a nickel plating solution and vacuumed to 2×10 -2 Pa, after negative pressure immersion for 15 min, the carbon nanotubes were separated by centrifugation, heated to 400 ° C, calcined under hydrogen atmosphere for 30 min, and cooled to room temperature to obtain nickel-plated carbon nanotubes;

[0089] Wherein, the preparation method of the acid-treated carbon nanotubes is:

[0090] The carbon nanotubes were placed in a muffle furnace, heated to 450°C under inert gas protection, and calcined for 10 minutes. After cooling to room temperature, they were placed in a 1:1 mixture of concentrated nitric acid and concentrated sulfuric acid, heated to 60°C, and subjected to ultrasonic oscillation dispersion treatment for 4 hours. The mixture was then centrifuged, washed with deionized water until neutral, and dried to constant weight to obtain acid-treated carbon nanotubes.

[0091] The nickel plating solution is composed of 35g / L nickel sulfate, 10g / L ammonium chloride, 10g / L sodium citrate, 5g / L sodium phosphite and the balance deionized water;

[0092] S2. Add nickel-plated carbon nanotubes to deionized water and disperse them by ultrasonic oscillation for 8 hours. Then, add nickel nitrate and disperse them uniformly by ultrasonic oscillation to obtain a reaction solution. Add hydrazine hydrate to the solution until the pH value of the system is 10. Heat the solution to 65°C and allow the reaction to stand at this temperature for 6 hours. Then, stop heating, centrifuge, remove the supernatant, and freeze-dry the remaining bottom mixture. Wash the mixture three times with anhydrous ethanol and deionized water, respectively, and freeze-dry again to obtain primary nickel powder.

[0093] Wherein, the reaction solution comprises, by weight, 100 parts of deionized water, 0.1 parts of nickel-plated carbon nanotubes, and 1.5 parts of nickel nitrate;

[0094] S3. In parts by weight, 2 parts of primary nickel powder, 10 parts of xylene, and 0.5 parts of aniline were mixed, 100 parts of deionized water and 4 parts of camphorsulfonic acid were added thereto, and the mixture was stirred and mixed. After ultrasonic dispersion for 15 minutes to emulsify, the reaction system was cooled to 4°C, and the mixture was added dropwise to an ammonium persulfate solution containing 0.6 parts of ammonium persulfate at a temperature of 4°C. After reacting for 5 hours, the mixture was centrifuged and precipitated, and then washed three times with anhydrous ethanol, anhydrous acetone, and deionized water, respectively, and then vacuum dried to constant weight to obtain the conductive nickel powder.

[0095] Comparative Example 3

[0096] A method for preparing conductive nickel powder comprises the following steps:

[0097] Compared with Example 1, this comparative example did not perform step S3;

[0098] S1. The acid-treated carbon nanotubes were immersed in a 0.1M palladium chloride solution and a 0.1M tin chloride solution, respectively. After ultrasonic dispersion sensitization for 15 minutes, they were placed in a nickel plating solution and vacuumed to 2×10 -2 Pa, after negative pressure immersion for 15 min, the carbon nanotubes were separated by centrifugation, heated to 400 ° C, calcined under hydrogen atmosphere for 30 min, and cooled to room temperature to obtain nickel-plated carbon nanotubes;

[0099] Wherein, the preparation method of the acid-treated carbon nanotubes is:

[0100] The carbon nanotubes were placed in a muffle furnace, heated to 450°C under inert gas protection, and calcined for 10 minutes. After cooling to room temperature, they were placed in a 1:1 mixture of concentrated nitric acid and concentrated sulfuric acid, heated to 60°C, and subjected to ultrasonic oscillation dispersion treatment for 4 hours. The mixture was then centrifuged, washed with deionized water until neutral, and dried to constant weight to obtain acid-treated carbon nanotubes.

[0101] The nickel plating solution is composed of 35g / L nickel sulfate, 10g / L ammonium chloride, 10g / L sodium citrate, 5g / L sodium phosphite and the balance deionized water;

[0102] S2. Add nickel-plated carbon nanotubes to deionized water and disperse them under ultrasonic oscillation for 8 hours. Then, add n-butanol and cetyltrimethylammonium bromide and mix them. After stirring until uniform, add nickel nitrate and disperse them under ultrasonic oscillation to obtain a reaction solution. Hydrazine hydrate is added to the solution until the pH of the system is 10. The solution is heated to 65°C and allowed to react at this constant temperature for 6 hours. Heating is then stopped and the solution is centrifuged. The supernatant is removed and the remaining bottom mixture is lyophilized. The mixture is then washed three times with anhydrous ethanol and three times with deionized water, and then lyophilized again to obtain a conductive nickel powder.

[0103] Wherein, the reaction solution includes, by weight, 100 parts of deionized water, 0.15 parts of nickel-plated carbon nanotubes, 1.5 parts of n-butanol, 5 parts of hexadecyltrimethylammonium bromide and 1.5 parts of nickel nitrate.

[0104] Testing: Conductive adhesive was prepared using the conductive nickel powder prepared in Examples 1-5 and Comparative Examples 1-3 as raw materials. The preparation method of the conductive adhesive is as follows:

[0105] To 10 parts of No. 4404 acrylic resin, 4 parts of conductive nickel powder and 30 parts of xylene were added by weight, and the mixture was stirred for 10 minutes, followed by ultrasonic dispersion for 30 minutes. Then, 90 parts of No. 4404 acrylic resin were added, and the mixture was stirred for 20 minutes and ultrasonic dispersion for 15 minutes, followed by high-speed shear mixing for 30 minutes to obtain a conductive adhesive.

[0106] Conductive adhesive was applied to an insulating resin substrate and dried to form a 150μm dry film thickness. Its conductivity was tested using an SZT-2 DC four-probe tester. Its electromagnetic shielding effectiveness was tested using an Agilent 4396B network analyzer and a far-field shielding effectiveness coaxial tester in accordance with SJ-20524-1995.

[0107] The test results are shown in Table 1 below.

[0108] Table 1. Performance test results of conductive adhesives prepared using conductive nickel powders prepared in Examples 1-5 and Comparative Examples 1-3 as raw materials

[0109] Conductivity (S / cm) Shielding effectiveness at 30MHz (db) Shielding effectiveness at 300MHz (db) Example 1 152 72 98 Example 2 156 73 98 Example 3 164 75 102 Example 4 166 75 105 Example 5 163 73 100 Comparative Example 1 128 56 80 Comparative Example 2 159 68 84 Comparative Example 3 144 66 92

[0110] Comparative Examples a and b conductive adhesives were also provided;

[0111] The preparation method of the conductive adhesive of comparative example a is as follows:

[0112] To 10 parts of No. 4404 acrylic resin, 1.5 parts of the conductive nickel powder prepared in Example 1 and 30 parts of xylene were added by weight. The mixture was stirred and mixed for 10 minutes, and then ultrasonically dispersed for 30 minutes. 90 parts of No. 4404 acrylic resin were then added. The mixture was stirred and mixed for 20 minutes and ultrasonically dispersed for 15 minutes, and then high-speed shear mixing was performed for 30 minutes to obtain a conductive adhesive.

[0113] The preparation method of the conductive adhesive in comparative example b is as follows:

[0114] To 10 parts of No. 4404 acrylic resin, 1.5 parts of the conductive nickel powder prepared in Comparative Example 1 and 30 parts of xylene were added by weight. The mixture was stirred and mixed for 10 minutes, and then ultrasonically dispersed for 30 minutes. 90 parts of No. 4404 acrylic resin were then added. The mixture was stirred and mixed for 20 minutes and ultrasonically dispersed for 15 minutes, and then high-speed shear mixing was performed for 30 minutes to obtain a conductive adhesive.

[0115] The conductivity of Comparative Examples a and b was tested again using a SZT-2 DC four-probe tester. The test results are shown in Table 2.

[0116] Table 2. Conductivity test results of conductive adhesives of comparative examples a and b

[0117] Comparative Example a Comparative Example b Conductivity (S / cm) 114 45

[0118] As can be seen from the above, the difference between the data of Examples 1 and 2 of the present application is that the nickel concentration in the nickel plating solution in step S1 is increased in Example 2, thereby increasing the nickel coating layer on the surface of the carbon nanotubes. This facilitates the deposition of more nickel powder around the carbon nanotubes in the subsequent step S, forming conductive particles with a larger aspect ratio. The conductive nickel powder is more likely to form a conductive path when preparing the conductive adhesive, thereby improving the electrical conductivity. The improvement in electrical conductivity and conductive continuity is also beneficial for shielding electromagnetic waves.

[0119] Compared with Example 2, Example 3 of the present application further increases the amount of nickel-plated carbon nanotubes added in step S2, so that the prepared conductive adhesive has better conductivity, thereby achieving an improvement in electromagnetic wave shielding performance; and Example 4 of the present application further increases the amount of primary nickel powder added, so that the ratio of nickel powder to polyaniline in the prepared conductive nickel powder is further increased. Although polyaniline itself has certain conductive properties, it is still poorer than that of metal materials, and the conductive nickel powder prepared in the present application also has carbon nanotubes, which makes it easier to form a conductive path. Therefore, after increasing the ratio of nickel powder to polyaniline, the prepared conductive nickel powder The proportion of nickel powder in the glue is large, and the conductive performance is partially improved. In addition, the method of preparing nickel powder in this application is a soft template method, and the formed nickel powder has a large number of pores, which can achieve multiple refraction, absorption and shielding of high-frequency electromagnetic waves. Therefore, after increasing the proportion of nickel powder, the shielding effectiveness of the conductive glue against high-frequency electromagnetic waves is also improved; and in Example 5, although the addition rate of polyaniline is increased, since polyaniline is also conductive, it can also assist in achieving overlapping of conductive paths in the resin matrix. Therefore, compared with Example 4, the conductivity of Example 5 is not much reduced, but the high-frequency electromagnetic shielding effectiveness is reduced due to the lack of reflection and absorption of nickel powder.

[0120] In Comparative Example 1 of the present application, nickel-plated carbon nanotubes were not added, which made it more difficult to form a conductive path in the conductive adhesive, resulting in a decrease in conductivity, which in turn led to a subsequent decrease in electromagnetic wave shielding effectiveness. At the same time, the present application also provided Comparative Examples a and b, which used the conductive nickel powder prepared in Example 1 and Comparative Example 1 as raw materials, respectively, to prepare conductive adhesives on the basis of reducing the addition ratio. However, due to the lack of carbon nanotubes, the conductive nickel powder prepared in Comparative Example 1 was more difficult to overlap with each other to form a conductive path, and it was difficult to break through the percolation phenomenon, resulting in a significant decrease in the conductive performance of the material;

[0121] Comparative Example 2 of the present application does not use n-butanol and cetyltrimethylammonium bromide soft template method to prepare nickel powder. Therefore, the pore size of the prepared nickel powder is greatly reduced. Due to the lack of multiple reflection absorption of electromagnetic waves by the tiny pores, the electromagnetic shielding effectiveness is ultimately reduced.

[0122] In Comparative Example 3 of the present application, polyaniline was not prepared, which resulted in a reduction in the conductive path and affected the dispersion of nickel powder in the resin matrix, resulting in a double decrease in conductivity and shielding effectiveness.

[0123] Finally, it should be noted that the above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for preparing conductive nickel powder, characterized in that: The following steps are involved: S1. The acid-treated carbon nanotubes were immersed in palladium chloride and tin chloride solutions, respectively, and subjected to ultrasonic dispersion sensitization. The carbon nanotubes were then placed in a nickel plating solution and immersed under negative pressure. The carbon nanotubes were separated by centrifugation, heated and calcined under a hydrogen atmosphere, and then cooled to room temperature to obtain nickel-plated carbon nanotubes. S2. Add nickel-plated carbon nanotubes to deionized water, ultrasonically vibrate, add n-butanol and a surfactant, stir until uniform, add nickel nitrate, and ultrasonically disperse to obtain a reaction solution, to which hydrazine hydrate is added until the pH value of the system is 10-10.

5. After heating, the reaction is allowed to stand at a constant temperature. Heating is stopped, centrifuged, and the supernatant is removed. The remaining bottom mixed solution is freeze-dried, washed with anhydrous ethanol and deionized water, and freeze-dried to obtain a primary nickel powder; S3. Primary nickel powder, xylene, and aniline are mixed, deionized water and camphorsulfonic acid are added thereto, the mixture is stirred and mixed, ultrasonically dispersed and emulsified, the reaction system is cooled, and the mixture is added dropwise to an ammonium persulfate solution. After the reaction, the precipitate is separated by centrifugation, washed with anhydrous ethanol, anhydrous acetone, and deionized water, respectively, and vacuum dried to constant weight to obtain the conductive nickel powder.

2. The method for preparing a conductive nickel powder according to claim 1, wherein: In S1, the method for preparing the acid-treated carbon nanotubes is: The carbon nanotubes were placed in a muffle furnace, heated to 450-480°C under inert gas protection, and calcined for 10-15 minutes. After cooling to room temperature, they were placed in a 1:1 mixture of concentrated nitric acid and concentrated sulfuric acid, heated to 55-70°C, and subjected to ultrasonic oscillation dispersion treatment for 2-5 hours. The mixture was then centrifuged, washed with deionized water until neutral, and dried to constant weight to obtain acid-treated carbon nanotubes.

3. The method for preparing a conductive nickel powder according to claim 1, wherein: In S1, the concentration of the palladium chloride solution is 0.1-0.15M, and the concentration of the tin chloride solution is 0.1-0.15M; the time of the ultrasonic dispersion sensitization treatment is 15-30 minutes, the negative pressure immersion time is 10-20 minutes, the temperature is raised to 400-450°C, and the calcination time is 30-60 minutes.

4. The method for preparing a conductive nickel powder according to claim 1, wherein: In S1, the nickel plating solution contains 35-60 g / L of nickel sulfate, 10-15 g / L of ammonium chloride, 10-15 g / L of sodium citrate, 5-10 g / L of sodium phosphite, and the balance is water.

5. The method for preparing a conductive nickel powder according to claim 1, wherein: In S2, the reaction solution includes, by weight, 100 parts of deionized water, 0.08-0.15 parts of nickel-plated carbon nanotubes, 1.5-2.5 parts of n-butanol, 5-8 parts of a surfactant, and 1.5-2.5 parts of nickel nitrate.

6. The method for preparing a conductive nickel powder according to claim 1, wherein: In S2, the surfactant is cetyltrimethylammonium bromide; the ultrasonic oscillation dispersion time is 8-12 hours, the temperature is raised to 60-70° C., and the constant temperature static reaction time is 4-8 hours.

7. The method for preparing a conductive nickel powder according to claim 1, wherein: In S3, the mixed solution includes, by weight, 1.5-5 parts of primary nickel powder, 10-15 parts of xylene, 0.45-1.5 parts of aniline, 100 parts of deionized water, and 4-5 parts of camphorsulfonic acid; the ammonium persulfate solution contains 0.6-2 parts of ammonium persulfate; the ultrasonic dispersion time is 15-30 minutes, the mixture is cooled to 0-4°C, the temperature of the ammonium persulfate solution is 2-4°C, and the reaction time is 3-8 hours.

8. A conductive nickel powder, characterized in that: The preparation method is described in any one of claims 1 to 7.

9. An electronic product, characterized in that: The conductive nickel powder according to claim 8 is included.

10. An electronic product according to claim 9, characterized in that: The conductive nickel powder in the electronic product exists in the form of a conductive component in the conductive adhesive.

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