Preparation method and preparation device of nano nickel-based powder
By employing a segmented reaction and freezing preparation method and controlling the complexing agent, the problems of size uniformity and dispersibility of nano-nickel-based powders were solved, achieving controllable morphology and reduced cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGDONG UNIV OF TECH
- Filing Date
- 2026-01-23
- Publication Date
- 2026-05-15
AI Technical Summary
Existing methods for preparing nano-nickel-based powders suffer from problems such as poor size uniformity, poor dispersibility, high production costs, and uncontrollable morphology.
A segmented reaction and freezing preparation method was adopted, which combines high-temperature short-time nucleation, medium-temperature long-time growth and low-temperature freezing, and uses a complexing agent to regulate the reaction to prepare nickel-based nanoparticles.
This method achieves size uniformity, dispersibility, and morphology controllability of nano-nickel-based powders, reduces production costs, and avoids dependence on high vacuum and high temperature conditions.
Smart Images
Figure CN122033260A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nickel-based powder technology, and in particular to a method and apparatus for preparing nano-nickel-based powder. Background Technology
[0002] As an important class of inorganic functional materials, nano-nickel and its alloy powders (i.e., nano-nickel-based powders) have wide applications in high-end fields such as aerospace, catalytic reactions, battery electrodes, high-frequency magnetic devices and protective coatings due to their unique small size effect, surface effect and excellent mechanical, catalytic and magnetic properties at the nanoscale.
[0003] Currently, the mainstream preparation methods for nano-nickel-based powders include the following two categories: (1) Chemical reduction method: This method usually uses a reducing agent in the liquid phase to reduce nickel ions to metallic nickel atoms and grow them into nanoparticles. The nanoparticles are then purified and dried to obtain nano-nickel-based powder. Although the process is relatively simple, it is difficult to achieve instantaneous molecular-level mixing when the reducing agent is added dropwise during the reaction. This can easily lead to the formation of "hot spots" with excessively high local concentrations in the system, resulting in drastic fluctuations in the reduction reaction kinetics and the coexistence of explosive nucleation and slow growth regions. This causes severe agglomeration of nanoparticles and a wide particle size distribution, resulting in poor dispersibility and size uniformity of the final nano-nickel-based powder, which can easily affect the performance stability of the material.
[0004] (2) Vapor-phase condensation method: This method prepares nanoparticles by vaporizing high-purity nickel at high temperature and then condensing the vapor in an inert atmosphere. Although nano- or submicron-sized powders can be obtained, the process depends on a high vacuum and high-purity environment, and the preparation conditions are relatively harsh, which can easily increase production costs. At the same time, it is necessary to vaporize high-purity nickel at high temperature, which leads to high energy consumption and further increases production costs.
[0005] Furthermore, the inherent defects of the above-mentioned traditional processes make it difficult to avoid the irregular growth of nanoparticles (such as dendrites and lamellar structures), resulting in the final nickel-based nanoparticle powder having a non-spherical morphology that is difficult to control.
[0006] In summary, existing methods for preparing nickel-based nanoparticles generally suffer from drawbacks such as poor size uniformity, poor dispersibility, high production costs, and uncontrollable morphology. Summary of the Invention
[0007] The purpose of this invention is to provide a method and apparatus for preparing nano-nickel-based powders, which can help ensure the size uniformity, dispersibility and morphology control of nano-nickel-based powders while reducing production costs, thus overcoming the shortcomings of the prior art.
[0008] To achieve this objective, the present invention adopts the following technical solution: A method for preparing nano-nickel-based powder includes the following steps: A. Mix the nickel salt, reducing agent, additive and solvent evenly, and adjust the pH value to 8-12 to obtain the precursor solution; The additives include complexing agents; B. The precursor solution was reacted sequentially at the nucleation temperature zone and the growth temperature zone for 10–60 s and 10–60 min respectively, and then frozen at the freezing temperature zone for 5–20 min to obtain a mixture of nano-nickel-based particles. Wherein, the temperature of the nucleation temperature range is higher than the temperature of the growth temperature range, and the temperature of the growth temperature range is higher than the temperature of the freezing temperature range; C. After separating, washing and drying the mixture of nano-nickel-based particles in sequence, nano-nickel-based powder is obtained.
[0009] Further, in step A, the concentration of nickel salt in the precursor solution is 0.05–1.5 mol / L.
[0010] Further, in step A, the molar ratio of the nickel salt to the reducing agent is 1:(1.2~4). The molar ratio of the nickel salt to the complexing agent is 1:(1-3).
[0011] Further, in step A, the nickel salt includes at least one of nickel sulfate, nickel chloride, nickel formate, nickel acetate, nickel nitrate, nickel methanesulfonate, nickel aminosulfonate, nickel hypophosphite, nickel carbonate, and nickel hydroxide; The reducing agent includes at least one of sodium hypophosphite, sodium hypophosphite, potassium hypophosphite, sodium borohydride, potassium borohydride, dimethylamine borane, lithium borohydride, sodium mercaptopropane sulfonate, sodium polydithiopropane sulfonate, and hydroquinone.
[0012] Furthermore, step B also includes: During the reaction at the growth temperature range, a nickel salt solution is added to the precursor solution, and the type of nickel salt in the nickel salt solution is the same as the type of nickel salt in the precursor solution.
[0013] Furthermore, step B also includes: An alkaline solution is added to the precursor solution during the reaction at the growth temperature range.
[0014] Furthermore, in step B, the temperature of the nucleation temperature range is 61–100°C; The temperature range for the growth temperature is 30–60°C. The freezing temperature range is 0–25°C.
[0015] An apparatus for preparing nano-nickel-based powder, used to realize the above-mentioned method for preparing nano-nickel-based powder, includes a first storage container 1, a second storage container 2, a nucleation reaction container 3, a conveying pipe 4, a growth reaction container 5, a freezing container 6, and a collection container 7. The feed pipe 4 has a first feed inlet, a second feed inlet, and a discharge outlet. The first storage container 1, the nucleation reaction container 3, and the first feed inlet are interconnected. The discharge outlet of the second storage container 2 is interconnected with the second feed inlet. The discharge outlet, the growth reaction container 5, the freezing container 6, and the collection container 7 are interconnected in sequence. The nucleation reaction vessel 3 is used to realize the reaction of the precursor solution in the nucleation temperature range, the growth reaction vessel 5 is used to realize the reaction of the precursor solution in the growth temperature range, and the freezing vessel 6 is used to realize the freezing of the precursor solution in the freezing temperature range. A first valve for opening and closing the first storage container 1 is provided between the first storage container 1 and the nucleation reaction container 3; A second valve for opening and closing the second storage container 2 is provided between the second storage container 2 and the second inlet. A third valve for opening and closing the nucleation reaction vessel 3 is provided between the nucleation reaction vessel 3 and the first feed inlet; A fourth valve for opening and closing the growth reaction container 5 is provided between the growth reaction container 5 and the freezing container 6; A fifth valve is provided between the freezing container 6 and the collection container 7 to open and close the freezing container 6.
[0016] Furthermore, both the nucleation reaction vessel 3 and the growth reaction vessel 5 include a reaction tube 51 and a water bath ultrasonic cooker 52. The reaction tube 51 is located inside the water bath ultrasonic cooker 52, and the water bath ultrasonic cooker 52 is used to heat and / or sonicate the reaction tube 51. The inlet of the reaction tube 51 of the nucleation reaction vessel 3 is connected to the outlet of the first storage container 1, and the outlet of the reaction tube 51 of the nucleation reaction vessel 3 is connected to the first inlet. The inlet of the reaction tube 51 of the growth reaction vessel 5 is connected to the outlet, and the outlet of the reaction tube 51 of the growth reaction vessel 5 is connected to the inlet of the freezing container 6. The third valve is provided between the reaction tube 51 of the nucleation reaction vessel 3 and the first feed inlet; The fourth valve is provided between the reaction tube 51 of the growth reaction vessel 5 and the freezing vessel 6.
[0017] Furthermore, the freezing container 6 includes a freezing tube 61 and a low-temperature water bath 62. The freezing tube 61 is located inside the low-temperature water bath 62, and the low-temperature water bath 62 is used to cool the freezing tube 61. The inlet of the freezing tube 61 is connected to the outlet of the reaction tube 51 of the growth reaction container 5. The fifth valve is provided between the freezing tube 61 and the collection container 7.
[0018] The technical solution provided by this invention may include the following beneficial effects: 1. In this technical solution, the nickel salt in the precursor solution undergoes a redox reaction with the reducing agent, reducing the nickel salt to nickel nanoparticles. The chemical composition of the product can be directionally controlled by selecting different reducing agents. Specifically: if a common reducing agent is used, nickel nanoparticles are mainly obtained; if a phosphorus- or boron-containing reducing agent (such as sodium hypophosphite or sodium borohydride) is selected, the reduction potentials of phosphorus and boron are similar to those of nickel, causing them to be reduced and deposited together with nickel ions, forming alloy particles through in-situ doping. Therefore, this technical solution can prepare various nickel-based nanoparticles, such as nickel nanoparticles, nickel-phosphorus alloys, nickel-boron alloys, or nickel-phosphorus-boron alloys, by selecting different types of reducing agents. The mixture containing the above-mentioned nickel-based nanoparticles (i.e., the nickel-based nanoparticle mixture) is then separated, washed, and dried to obtain the corresponding nickel-based nanoparticle powder. The type of the final product depends entirely on the type of reducing agent selected.
[0019] 2. This technical solution achieves the size uniformity of nano-nickel-based powders by combining high-temperature short-time nucleation, medium-temperature long-time growth, and low-temperature freezing. Specifically, in the initial nucleation temperature range (the highest temperature), the high temperature drives a violent reaction between the nickel salt and the reducing agent in the precursor solution, achieving explosive synchronous nucleation within a very short time (10–60 s). This ensures that all crystal nuclei are generated almost simultaneously, laying the foundation for the size uniformity of the final product. Simultaneously, this technical solution uses a complexing agent (such as sodium citrate) to coordinate with nickel ions, slowing down the free Ni... 2+ The concentration of the material slows down the nucleation rate, preventing the instantaneous generation of a large number of crystal nuclei of varying sizes, which also helps ensure the size uniformity of the product. Furthermore, in the growth temperature range (temperature decreases), the system transitions to mild conditions and is maintained for a longer period (10–60 min), allowing the already formed crystal nuclei to slowly and uniformly consume the remaining reactants and grow. This process effectively avoids the generation of new crystal nuclei, ensuring that all particles grow synchronously. In addition, in the freezing temperature range (lowest temperature), the low-temperature environment abruptly terminates all reactions and particle ripening processes in the system, freezing the size and morphology of the already formed particles and preventing inhomogeneity caused by overgrowth or agglomeration.
[0020] 3. In the growth temperature range of this technical solution, the complexing agent can be selectively adsorbed onto specific crystal surfaces, guiding the particles to grow in a specific shape (such as spheres). The low temperature in the freezing temperature range can prevent particle size and morphology differentiation due to differences in growth time or Oswald ripening (large particles grow while small particles dissolve), thus ensuring that the obtained nickel-based nanoparticles are spherical and that the morphology of the nickel-based nanoparticles is controllable. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the structure of a device for preparing nano-nickel-based powder according to the present invention.
[0022] Figure 2 This is a scanning electron microscope image of the nickel nanoparticles prepared by a method for preparing nickel nanoparticles according to Example 1 of the present invention.
[0023] Figure 3 This is a scanning electron microscope image of the nickel nanoparticles prepared by a method for preparing nickel nanoparticles according to Example 2 of the present invention.
[0024] Among them: first storage container 1, second storage container 2, nucleation reaction container 3, conveying pipe 4, first feed port, second feed port, discharge port, growth reaction container 5, reaction tube 51, water bath ultrasonic cooker 52, freezing container 6, freezing tube 61, low temperature water bath cooker 62, and collection container 7. Detailed Implementation
[0025] This technical solution provides a method for preparing nano-nickel-based powder, including the following steps: A. Mix the nickel salt, reducing agent, additive and solvent evenly, and adjust the pH value to 8-12 to obtain the precursor solution; The additives include complexing agents; B. The precursor solution was reacted sequentially at the nucleation temperature zone and the growth temperature zone for 10–60 s and 10–60 min respectively, and then frozen at the freezing temperature zone for 5–20 min to obtain a mixture of nano-nickel-based particles. Wherein, the temperature of the nucleation temperature range is higher than the temperature of the growth temperature range, and the temperature of the growth temperature range is higher than the temperature of the freezing temperature range; C. After separating, washing and drying the mixture of nano-nickel-based particles in sequence, nano-nickel-based powder is obtained.
[0026] To address the shortcomings of existing technologies in producing nano-nickel-based powders, such as poor size uniformity, poor dispersibility, high production costs, and uncontrollable morphology, this technical solution proposes a method for preparing nano-nickel-based powders. This method comprises three steps: A (preparation of precursor solution), B (segmented reaction and freezing), and C (separation and purification). By optimizing the preparation process and selecting the best raw materials, this method helps to ensure the size uniformity, dispersibility, and controllable morphology of the prepared nano-nickel-based powders while reducing production costs, thus meeting practical application requirements.
[0027] Specifically, in this technical solution, the nickel salt in the precursor solution undergoes a redox reaction with the reducing agent, reducing the nickel salt to nickel nanoparticles. Furthermore, the chemical composition of the product can be directionally controlled by selecting different reducing agents. Specifically: if a common reducing agent is used, nickel nanoparticles are mainly obtained; if a phosphorus- or boron-containing reducing agent (such as sodium hypophosphite or sodium borohydride) is selected, the reduction potentials of phosphorus and boron are similar to those of nickel, causing them to be reduced and deposited together with nickel ions, forming alloy particles through in-situ doping. Therefore, this technical solution can prepare various nickel-based nanoparticles, such as nickel nanoparticles, nickel-phosphorus alloys, nickel-boron alloys, or nickel-phosphorus-boron alloys, by selecting different types of reducing agents. The mixture containing the above-mentioned nickel-based nanoparticles (i.e., the nickel-based nanoparticle mixture) undergoes subsequent separation, washing, and drying to obtain the corresponding nickel-based nanoparticle powder. The type of the final product depends entirely on the type of reducing agent selected.
[0028] Secondly, this technical solution achieves the size uniformity of nano-nickel-based powders by combining high-temperature short-time nucleation, medium-temperature long-time growth, and low-temperature freezing. Specifically, in the initial nucleation temperature range (the highest temperature), the high temperature drives a violent reaction between the nickel salt and the reducing agent in the precursor solution, achieving explosive synchronous nucleation within an extremely short time (10–60 s). This ensures that all crystal nuclei are generated almost simultaneously, laying the foundation for the size uniformity of the final product. Simultaneously, this technical solution uses a complexing agent (such as sodium citrate) to coordinate with nickel ions, slowing down the free Ni... 2+ The concentration of the material slows down the nucleation rate, preventing the instantaneous generation of a large number of crystal nuclei of varying sizes, which also helps ensure the size uniformity of the product. Furthermore, in the growth temperature range (temperature decreases), the system transitions to mild conditions and is maintained for a longer period (10–60 min), allowing the already formed crystal nuclei to slowly and uniformly consume the remaining reactants and grow. This process effectively avoids the generation of new crystal nuclei, ensuring that all particles grow synchronously. In addition, in the freezing temperature range (lowest temperature), the low-temperature environment abruptly terminates all reactions and particle ripening processes in the system, freezing the size and morphology of the already formed particles and preventing inhomogeneity caused by overgrowth or agglomeration.
[0029] Furthermore, in the growth temperature range of this technical solution, the complexing agent can be selectively adsorbed onto specific crystal faces, guiding the particles to grow in a specific shape (such as spheres). The low temperature in the freezing temperature range can prevent particle size and morphology differentiation due to differences in growth time or Oswald ripening (large particles grow while small particles dissolve), thus ensuring that the obtained nickel-based nanoparticles are spherical and that the morphology of the nickel-based nanoparticles is controllable.
[0030] Finally, this technical solution utilizes high-temperature, short-time nucleation to ensure that all crystal nuclei are generated almost simultaneously, possessing nearly identical growth starting points and growth times, thus laying the foundation for the excellent dispersibility of the final product. During the freezing stage at the end of the reaction, the low-temperature environment reduces the surface energy and Brownian motion of the particles, helping to maintain their dispersed state. In the post-processing stage, thorough washing removes electrolytes that may cause bridging and agglomeration, and drying eliminates capillary forces, thereby obtaining nano-nickel-based powders with excellent dispersibility.
[0031] It should be noted that this technical solution completely avoids the complex high-vacuum environment required by the gas-phase condensation method and the energy consumption of vaporizing high-purity metallic nickel at high temperatures. The reduction, nucleation and growth of nickel ions in the solution can be achieved under normal or low pressure, which greatly reduces the energy consumption of the production process and the dependence on extreme environmental conditions, thereby helping to reduce production costs.
[0032] It should be further explained that this technical solution involves adding a complexing agent to the precursor solution and adjusting the pH to 8-12 to allow nickel ions (Ni...) to... 2+ At room temperature, it forms a chelate with a complexing agent, exhibiting extremely high stability, thereby releasing free Ni in solution that can directly participate in the reduction reaction. 2+ The concentration was reduced to an extremely low level, effectively suppressing the spontaneous and uncontrollable reduction reaction of the precursor at room temperature, fundamentally avoiding product performance fluctuations and uncontrollability caused by premature reaction. When the system is heated to the reaction temperature, the chelate structure is destroyed, nickel ions are released, thereby initiating the preset reduction reaction, ensuring the controllability and consistency of product performance.
[0033] It should be further noted that the solvent in this technical solution can be deionized water, ketone solvents (such as acetone or butanone), or alcohol solvents (such as ethanol), etc., and the specific type is not limited here. In addition, in step A of this technical solution, a 0.1-1 mol / L sodium hydroxide solution can be used to adjust the pH value, and the specific adjustment method is not limited.
[0034] Preferably, the separation in step C specifically involves: loading the mixture of nano-nickel-based particles into a centrifuge tube for centrifugation to obtain a precipitate; The specific washing method is as follows: wash the precipitate repeatedly with pure water until the washed liquid is colorless and transparent, thus obtaining a solid. The specific drying method is as follows: the solid is dried multiple times, and the weight is weighed after each drying until the weights of two consecutive weighings are consistent, then the drying is complete and nano-nickel-based powder is obtained.
[0035] Optimizing the specific methods of separation, washing, and drying can help ensure the performance of nano-nickel-based powders and improve their purity.
[0036] Preferably, the complexing agent includes at least one selected from ethylenediamine, tetrasodium ethylenediaminetetraacetate, tartaric acid, potassium sodium tartrate, sodium gluconate, citric acid, sodium citrate, salicylic acid, and sodium pyrophosphate.
[0037] Different complexing agents exhibit varying chelation stability constants, thermal dissociation characteristics, and functional groups (such as carboxyl, hydroxyl, and amino groups) with nickel ions. This allows for the selection of the most suitable complexing agent based on the specific performance requirements of the target product (such as particle size, morphology, and crystallinity), the type of reducing agent chosen, and cost considerations. Consequently, while ensuring the stability of the solution at room temperature, the reaction initiation rate after heating and the growth kinetics of nickel-based nanoparticles can be controlled, thereby optimizing the performance of the final product.
[0038] Preferably, the additive further includes at least one of a dispersant, an emulsifier, and a buffer; The dispersant includes at least one of polyvinylpyrrolidone, polyethylene glycol, chitosan, gelatin, and gum arabic; The emulsifier includes at least one of Tween-20, Tween-80, OP-10, TX-10, and TX-15; The buffer includes at least one of carbonate and borate.
[0039] This technical solution specifies that the additives also include at least one of dispersants, emulsifiers, and buffers. This allows the dispersants and emulsifiers to adsorb onto the surface of the nickel-based nanoparticles and form a coating layer. Through steric hindrance and other effects, the powder is stably dispersed in the solution, preventing the aggregation and sedimentation of the nickel-based nanoparticles, thereby dispersing and controlling the particle size. Simultaneously, the buffer neutralizes the hydrogen ions generated during the reaction, maintaining a stable pH value in the reaction system and avoiding negative impacts on the reaction rate and particle quality due to pH fluctuations. This ensures a smooth nickel ion reduction process and improves the uniformity of the size distribution of the obtained nickel-based nanoparticles.
[0040] To further clarify, in step A, the concentration of nickel salt in the precursor solution is 0.05–1.5 mol / L.
[0041] If the concentration of nickel salt in the precursor solution is too low (<0.05 mol / L), it will lead to insufficient nucleation density and a decrease in the yield of nickel nanoparticles. If the concentration of nickel salt in the precursor solution is too high (>1.5 mol / L), it is prone to causing excessively rapid reaction, excessive particle growth, and severe agglomeration, which can easily reduce the uniformity and dispersibility of the nickel nanoparticles. Therefore, in a preferred embodiment of this technical solution, the concentration of nickel salt in the precursor solution is limited to 0.05–1.5 mol / L, which provides a suitable ionic environment and material basis for the controlled nucleation and uniform growth of nickel nanoparticles within this concentration range, thereby helping to ensure the performance of the final nickel nanoparticles.
[0042] To further explain, in step A, the molar ratio of the nickel salt to the reducing agent is 1:(1.2~4). The molar ratio of the nickel salt to the complexing agent is 1:(1-3).
[0043] If the molar ratio of nickel salt to reducing agent is too low, insufficient reduction of nickel ions will result in unreacted salt residue. If the molar ratio is too high, excessive reducing agent will decompose violently during the reaction or produce too many byproducts. These byproducts not only increase the cost and difficulty of post-processing but may also affect the purity and dispersibility of the final nickel-based nanoparticles. Therefore, this technical solution limits the molar ratio of nickel salt to reducing agent, which helps ensure the reaction proceeds completely and that the resulting nickel-based nanoparticle mixture is easy to purify, thereby ensuring the performance of the final nickel-based nanoparticles.
[0044] Furthermore, if the molar ratio of nickel salt to complexing agent is too low, incomplete complexation of nickel ions will occur, which is detrimental to ensuring the stability of the precursor solution at room temperature and will also lead to the hydrolysis of nickel ions, forming flocculent precipitates. If the molar ratio of nickel salt to complexing agent is too high, it will result in waste of raw materials. Therefore, this technical solution, by limiting the molar ratio of nickel salt to complexing agent, helps to ensure the stability of the precursor solution and avoid the hydrolysis of nickel ions while reducing costs.
[0045] To further explain, in step A, the nickel salt includes at least one of nickel sulfate, nickel chloride, nickel formate, nickel acetate, nickel nitrate, nickel methanesulfonate, nickel aminosulfonate, nickel hypophosphite, nickel carbonate, and nickel hydroxide. The reducing agent includes at least one of sodium hypophosphite, sodium hypophosphite, potassium hypophosphite, sodium borohydride, potassium borohydride, dimethylamine borane, lithium borohydride, sodium mercaptopropane sulfonate, sodium polydithiopropane sulfonate, and hydroquinone.
[0046] Nickel sulfate, nickel chloride, nickel formate, nickel acetate, nickel nitrate, nickel methanesulfonate, nickel aminosulfonate, nickel hypophosphite, nickel carbonate, and nickel hydroxide can all effectively provide nickel ions at different pH values without volatilizing and producing harmful gases, making them safe and reliable. Therefore, this technical solution limits the nickel salt to at least one of the above types. This not only allows for the selection of suitable raw materials according to actual needs, improving the flexibility of the solution, but also enhances the safety of the preparation method while effectively providing nickel ions.
[0047] Sodium hypophosphite, sodium hypophosphite, potassium hypophosphite, sodium borohydride, potassium borohydride, dimethylamineborane, lithium borohydride, sodium mercaptopropane sulfonate, sodium polydithiopropane sulfonate, and hydroquinone all possess strong reducing power, effectively reducing and depositing nickel ions while avoiding the harm to the human body caused by highly toxic reducing agents such as hydrazine hydrate. Therefore, this technical solution limits the reducing agent to at least one of the above types, which not only facilitates the selection of suitable raw materials according to actual needs and improves the flexibility of the solution, but also enhances the safety of the preparation method while ensuring the reducing power of the reducing agent.
[0048] To further explain, step B also includes: During the reaction at the growth temperature range, a nickel salt solution is added to the precursor solution, and the type of nickel salt in the nickel salt solution is the same as the type of nickel salt in the precursor solution.
[0049] In a preferred embodiment of this technical solution, uniform nanocrystal nuclei (seed crystals) are first generated at the nucleation temperature range. Then, by adding nickel salt solution at the growth temperature range, the nickel salt in the reaction system can be maintained at a low supersaturation, thereby effectively inhibiting the generation of new crystal nuclei. This allows newly added nickel ions to selectively deposit on the surface of existing seed crystals, achieving directional utilization of nickel salts and uniform epitaxial growth of seed crystals. Ultimately, monodisperse, narrowly sized, and spherical nano-nickel-based powders are obtained, achieving uniform size, dispersibility, and controllable morphology of the nano-nickel-based powders.
[0050] Preferably, the concentration of nickel salt in the nickel salt solution is 0.2 to 1.5 mol / L, and the amount of nickel salt solution added is 0.5 to 1% of the mass of the precursor solution, calculated by mass percentage.
[0051] To further explain, step B also includes: An alkaline solution is added to the precursor solution during the reaction at the growth temperature range.
[0052] This technical solution adds an alkaline solution during the reaction process at the growth temperature range to increase the pH value of the reaction system, promote the hydrolysis of the reducing agent, generate more active hydrogen atoms to reduce metal ions, thereby improving the reducing power of the reducing agent, triggering explosive nucleation, and rapidly depleting nickel ions in the reaction system, inhibiting the growth of nickel nanoparticles, and finally obtaining nickel nanoparticles with small particle size and relatively uniform distribution.
[0053] Preferably, the amount of alkaline solution added is 0.5 to 2% of the mass of the precursor solution, calculated as a percentage by mass.
[0054] This technical solution effectively increases the pH value of the reaction system without increasing costs by limiting the amount of alkaline solution added. This promotes the hydrolysis of the reducing agent, generates more active hydrogen atoms to promote the reduction of nickel ions and inhibit the growth of nickel nanoparticles, and further obtains nickel nanoparticles with uniform particle size distribution.
[0055] Preferably, the alkaline solution is a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 0.05–0.5 mol / L.
[0056] To further explain, in step B, the temperature of the nucleation temperature range is 61–100°C; The temperature range for the growth temperature is 30–60°C. The freezing temperature range is 0–25°C.
[0057] This technical solution utilizes a high-temperature-driven reaction within the nucleation temperature range of 61–100℃ to rapidly reach supersaturation, achieving explosive synchronous nucleation. Subsequently, the system is lowered to a growth temperature range of 30–60℃ to reduce the reaction rate, allowing the formed crystal nuclei to grow slowly and uniformly under mild conditions, effectively suppressing secondary nucleation. Finally, all reactions and ripening processes are rapidly terminated within a freezing temperature range of 0–25℃, locking in the final size and morphology of the particles, thereby facilitating the acquisition of highly uniform nickel-based nanoparticles.
[0058] An apparatus for preparing nano-nickel-based powder, used to realize the above-mentioned method for preparing nano-nickel-based powder, includes a first storage container 1, a second storage container 2, a nucleation reaction container 3, a conveying pipe 4, a growth reaction container 5, a freezing container 6, and a collection container 7. The feed pipe 4 has a first feed inlet, a second feed inlet, and a discharge outlet. The first storage container 1, the nucleation reaction container 3, and the first feed inlet are interconnected. The discharge outlet of the second storage container 2 is interconnected with the second feed inlet. The discharge outlet, the growth reaction container 5, the freezing container 6, and the collection container 7 are interconnected in sequence. The nucleation reaction vessel 3 is used to realize the reaction of the precursor solution in the nucleation temperature range, the growth reaction vessel 5 is used to realize the reaction of the precursor solution in the growth temperature range, and the freezing vessel 6 is used to realize the freezing of the precursor solution in the freezing temperature range. A first valve for opening and closing the first storage container 1 is provided between the first storage container 1 and the nucleation reaction container 3; A second valve for opening and closing the second storage container 2 is provided between the second storage container 2 and the second inlet. A third valve for opening and closing the nucleation reaction vessel 3 is provided between the nucleation reaction vessel 3 and the first feed inlet; A fourth valve for opening and closing the growth reaction container 5 is provided between the growth reaction container 5 and the freezing container 6; A fifth valve is provided between the freezing container 6 and the collection container 7 to open and close the freezing container 6.
[0059] This solution also proposes a device for preparing nano-nickel-based powders, which, when combined with the method for preparing nano-nickel-based powders, helps to ensure the size uniformity, dispersibility, and controllable morphology of nano-nickel-based powders while reducing production costs.
[0060] Specifically, the workflow of this device is as follows: The precursor solution is loaded into the first storage container 1, and the nickel salt solution or alkaline solution is loaded into the second storage container 2. The first valve is opened, and all other valves are closed, allowing the precursor solution to flow into and fill the nucleation reaction container 3 under gravity. The first valve is then closed, and the precursor solution is kept at a constant temperature in the nucleation reaction container 3 for 10–60 seconds to complete explosive nucleation, yielding a nucleation solution. Subsequently, the third valve is opened, transferring the entire nucleation solution to the growth reaction container 5. If, according to process requirements, no additional nickel salt solution or alkaline solution is needed during this process, the nucleation solution directly enters the growth reaction container 5 for reaction. If nickel salt solution or alkaline solution needs to be added according to process requirements, the second valve is opened simultaneously with the third valve, allowing the nickel salt solution or alkaline solution in the second storage container 2 to enter the growth reaction container 5 synchronously with the nucleation solution through the feed pipe 4. The reaction is carried out in the growth reaction container 5 at a constant temperature for 10-60 minutes to allow the crystal nuclei to grow uniformly and obtain a growth solution. Then, the second and third valves are closed and the fourth valve is opened to transfer the growth solution to the freezing container 6. The reaction is quickly terminated in the freezing container 6 for 5-20 minutes to stabilize the particle morphology and obtain a mixture of nano-nickel-based particles. Finally, the fourth valve is closed and the fifth valve is opened to allow the mixture of nano-nickel-based particles to flow into the collection container 7. The mixture of nano-nickel-based particles in the collection container is then separated, washed, and dried to obtain nano-nickel-based powder.
[0061] Further explanation: Both the nucleation reaction vessel 3 and the growth reaction vessel 5 include a reaction tube 51 and a water bath ultrasonic pot 52. The reaction tube 51 is located inside the water bath ultrasonic pot 52, and the water bath ultrasonic pot 52 is used to heat and / or sonicate the reaction tube 51. The inlet of the reaction tube 51 of the nucleation reaction vessel 3 is connected to the outlet of the first storage container 1, and the outlet of the reaction tube 51 of the nucleation reaction vessel 3 is connected to the first inlet. The inlet of the reaction tube 51 of the growth reaction vessel 5 is connected to the outlet, and the outlet of the reaction tube 51 of the growth reaction vessel 5 is connected to the inlet of the freezing container 6. The third valve is provided between the reaction tube 51 of the nucleation reaction vessel 3 and the first feed inlet; The fourth valve is provided between the reaction tube 51 of the growth reaction vessel 5 and the freezing vessel 6.
[0062] This technical solution places the reaction tube 51 inside a water bath ultrasonic cooker 52 equipped with heating and / or ultrasound. During the nucleation stage of nickel nanoparticles, the high temperature of the water bath ultrasonic cooker 52 and the ultrasonic cavitation work together to powerfully drive explosive and uniform nucleation and prevent early agglomeration. During the growth stage of nickel nanoparticles, the medium temperature (30-60℃) and moderate ultrasound promote the diffusion of reactants and surface modification, guide the uniform growth of crystal nuclei and maintain dispersion, thereby helping to ensure that the nickel nanoparticle powder has high size uniformity, excellent dispersibility and controllable morphology.
[0063] Further explanation: The freezing container 6 includes a freezing tube 61 and a low-temperature water bath 62. The freezing tube 61 is located inside the low-temperature water bath 62. The low-temperature water bath 62 is used to cool the freezing tube 61. The inlet of the freezing tube 61 is connected to the outlet of the reaction tube 51 of the growth reaction container 5. The fifth valve is provided between the freezing tube 61 and the collection container 7.
[0064] This technical solution sets the freezing container 6 as a freezing tube 61 and a low-temperature water bath 62. The low-temperature water bath 62 provides a constant low-temperature environment (such as 0-25℃), ensuring that the growth solution in the freezing tube 61 cools down rapidly and uniformly after transfer. This abruptly reduces or even completely stops all chemical reactions and particle ripening processes, freezing the size and morphology of the nickel nanoparticles at the end of the growth stage. This prevents performance differentiation caused by slow or uneven cooling, thus helping to ensure the size uniformity, dispersibility, and morphology controllability of the nickel nanoparticles.
[0065] The technical solution of the present invention will be further illustrated below through specific embodiments.
[0066] Example 1 A. Mix nickel sulfate, sodium hypophosphite, disodium ethylenediaminetetraacetate, and deionized water thoroughly and adjust the pH to 12 to obtain a precursor solution; the concentration of nickel sulfate in the precursor solution is 0.2 mol / L; the molar ratio of nickel sulfate to sodium hypophosphite is 1:3; the molar ratio of nickel sulfate to disodium ethylenediaminetetraacetate is 1:1. B. The precursor solution was reacted sequentially at a nucleation temperature of 80℃ and a growth temperature of 40℃ for 120s and 20min respectively; then frozen at a freezing temperature of 20℃ for 5min to obtain a mixture of nickel-based nanoparticles. C. The mixture of nano-nickel-based particles is placed into a centrifuge tube for centrifugation to obtain a precipitate; the precipitate is washed with pure water multiple times until the washed liquid is colorless and transparent to obtain a solid; the solid is dried multiple times, and weighed after each drying until the weights of two consecutive weighings are consistent, then the drying is complete and nano-nickel-based powder is obtained.
[0067] The size uniformity, dispersibility, and morphology controllability of the nickel-based nanoparticles obtained through the above steps in Example 1 were observed using a scanning electron microscope. The scanning electron microscope images of this example are shown below. Figure 2 As shown. The results show that the nano-nickel-based powder obtained in Example 1 has a uniform particle size, a spherical morphology, and high dispersibility, exhibiting high size uniformity, dispersibility, and morphology controllability.
[0068] Example 2 A. Mix nickel acetate, sodium borohydride, sodium citrate, polyvinylpyrrolidone, and deionized water thoroughly and adjust the pH to 10 to obtain a precursor solution; wherein the concentration of nickel acetate in the precursor solution is 0.05 mol / L; the concentration of polyvinylpyrrolidone in the precursor solution is 2.5 g / L; the molar ratio of nickel acetate to sodium borohydride is 1:2; and the molar ratio of nickel acetate to sodium citrate is 1:1. B. The precursor solution was reacted sequentially at a nucleation temperature of 70℃ and a growth temperature of 45℃ for 30s and 20min respectively. During the reaction at the growth temperature, a 0.2mol / L nickel acetate solution was added to the precursor solution. Then, the solution was frozen at a freezing temperature of 10℃ for 10min to obtain a mixture of nickel-based nanoparticles. The amount of nickel salt solution added was 0.5% of the mass of the precursor solution. C. The mixture of nano-nickel-based particles is placed into a centrifuge tube for centrifugation to obtain a precipitate; the precipitate is washed with pure water multiple times until the washed liquid is colorless and transparent to obtain a solid; the solid is dried multiple times, and weighed after each drying until the weights of two consecutive weighings are consistent, then the drying is complete and nano-nickel-based powder is obtained.
[0069] The size uniformity, dispersibility, and morphology controllability of the nickel-based nanoparticles obtained through the above steps in Example 2 were observed using a scanning electron microscope. The scanning electron microscope images of this example are shown below. Figure 3 As shown. The results show that the nickel-based nanoparticles obtained in Example 2 have uniform particle size, spherical morphology, and high dispersibility, exhibiting high size uniformity, dispersibility, and morphology controllability.
[0070] Example 3 A. Mix nickel chloride, sodium borohydride, potassium sodium tartrate, sodium carbonate, TX-10, and deionized water thoroughly and adjust the pH to 8 to obtain a precursor solution. The precursor solution contains 0.1 mol / L nickel chloride, 50 g / L sodium carbonate, and 2 g / L TX-10. The molar ratio of nickel chloride to sodium borohydride is 1:1.2, and the molar ratio of nickel chloride to potassium sodium tartrate is 1:2. B. The precursor solution was reacted sequentially at a nucleation temperature of 90℃ and a growth temperature of 30℃ for 30s and 40min respectively. During the reaction at the growth temperature, a 0.1mol / L sodium hydroxide solution was added to the precursor solution. Then, the solution was frozen at a freezing temperature of 5℃ for 5min to obtain a mixture of nickel-based nanoparticles. The amount of sodium hydroxide solution added was 0.5% of the mass of the precursor solution. C. The mixture of nano-nickel-based particles is placed into a centrifuge tube for centrifugation to obtain a precipitate; the precipitate is washed with pure water multiple times until the washed liquid is colorless and transparent to obtain a solid; the solid is dried multiple times, and weighed after each drying until the weights of two consecutive weighings are consistent, then the drying is complete and nano-nickel-based powder is obtained.
[0071] The size uniformity, dispersibility, and morphology controllability of the nickel-based nanoparticles obtained through the above steps in Example 3 were observed using a scanning electron microscope. The results showed that the nickel-based nanoparticles obtained in Example 3 had uniform particle size, spherical morphology, and high dispersibility, exhibiting high size uniformity, dispersibility, and morphology controllability.
[0072] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.
Claims
1. A method for preparing nano-nickel-based powder, characterized in that, Includes the following steps: A. Mix the nickel salt, reducing agent, additive and solvent evenly, and adjust the pH value to 8-12 to obtain the precursor solution; The additives include complexing agents; B. The precursor solution was reacted sequentially at the nucleation temperature zone and the growth temperature zone for 10–60 s and 10–60 min respectively, and then frozen at the freezing temperature zone for 5–20 min to obtain a mixture of nano-nickel-based particles. Wherein, the temperature of the nucleation temperature range is higher than the temperature of the growth temperature range, and the temperature of the growth temperature range is higher than the temperature of the freezing temperature range; C. After separating, washing and drying the mixture of nano-nickel-based particles in sequence, nano-nickel-based powder is obtained.
2. The method for preparing nano-nickel-based powder according to claim 1, characterized in that, In step A, the concentration of nickel salt in the precursor solution is 0.05–1.5 mol / L.
3. The method for preparing nano-nickel-based powder according to claim 1, characterized in that, In step A, the molar ratio of the nickel salt to the reducing agent is 1:(1.2-4). The molar ratio of the nickel salt to the complexing agent is 1:(1-3).
4. The method for preparing nano-nickel-based powder according to claim 1, characterized in that, In step A, the nickel salt includes at least one of nickel sulfate, nickel chloride, nickel formate, nickel acetate, nickel nitrate, nickel methanesulfonate, nickel aminosulfonate, nickel hypophosphite, nickel carbonate, and nickel hydroxide. The reducing agent includes at least one of sodium hypophosphite, sodium hypophosphite, potassium hypophosphite, sodium borohydride, potassium borohydride, dimethylamine borane, lithium borohydride, sodium mercaptopropane sulfonate, sodium polydithiopropane sulfonate, and hydroquinone.
5. The method for preparing nano-nickel-based powder according to claim 1, characterized in that, Step B also includes: During the reaction at the growth temperature range, a nickel salt solution is added to the precursor solution, and the type of nickel salt in the nickel salt solution is the same as the type of nickel salt in the precursor solution.
6. The method for preparing nano-nickel-based powder according to claim 1, characterized in that, Step B also includes: An alkaline solution is added to the precursor solution during the reaction at the growth temperature range.
7. The method for preparing nano-nickel-based powder according to claim 1, characterized in that, In step B, the temperature of the nucleation temperature range is 61–100°C; The temperature range for the growth temperature is 30–60°C. The freezing temperature range is 0–25°C.
8. An apparatus for preparing nano-nickel-based powder, characterized in that, The method for preparing the nano-nickel-based powder according to any one of claims 1 to 7 includes a first storage container 1, a second storage container 2, a nucleation reaction container 3, a conveying pipe 4, a growth reaction container 5, a freezing container 6, and a collection container 7. The feed pipe 4 has a first feed inlet, a second feed inlet, and a discharge outlet. The first storage container 1, the nucleation reaction container 3, and the first feed inlet are interconnected. The discharge outlet of the second storage container 2 is interconnected with the second feed inlet. The discharge outlet, the growth reaction container 5, the freezing container 6, and the collection container 7 are interconnected in sequence. The nucleation reaction vessel 3 is used to realize the reaction of the precursor solution in the nucleation temperature range, the growth reaction vessel 5 is used to realize the reaction of the precursor solution in the growth temperature range, and the freezing vessel 6 is used to realize the freezing of the precursor solution in the freezing temperature range. A first valve for opening and closing the first storage container 1 is provided between the first storage container 1 and the nucleation reaction container 3; A second valve for opening and closing the second storage container 2 is provided between the second storage container 2 and the second inlet. A third valve for opening and closing the nucleation reaction vessel 3 is provided between the nucleation reaction vessel 3 and the first feed inlet; A fourth valve for opening and closing the growth reaction container 5 is provided between the growth reaction container 5 and the freezing container 6; A fifth valve is provided between the freezing container 6 and the collection container 7 to open and close the freezing container 6.
9. The apparatus for preparing nano-nickel-based powder according to claim 8, characterized in that, Both the nucleation reaction vessel 3 and the growth reaction vessel 5 include a reaction tube 51 and a water bath ultrasonic pot 52. The reaction tube 51 is located inside the water bath ultrasonic pot 52, and the water bath ultrasonic pot 52 is used to heat and / or sonicate the reaction tube 51. The inlet of the reaction tube 51 of the nucleation reaction vessel 3 is connected to the outlet of the first storage container 1, and the outlet of the reaction tube 51 of the nucleation reaction vessel 3 is connected to the first inlet. The inlet of the reaction tube 51 of the growth reaction vessel 5 is connected to the outlet, and the outlet of the reaction tube 51 of the growth reaction vessel 5 is connected to the inlet of the freezing container 6. The third valve is provided between the reaction tube 51 of the nucleation reaction vessel 3 and the first feed inlet; The fourth valve is provided between the reaction tube 51 of the growth reaction vessel 5 and the freezing vessel 6.
10. The apparatus for preparing nano-nickel-based powder according to claim 9, characterized in that, The freezing container 6 includes a freezing tube 61 and a low-temperature water bath 62. The freezing tube 61 is located inside the low-temperature water bath 62, and the low-temperature water bath 62 is used to cool the freezing tube 61. The inlet of the freezing tube 61 is connected to the outlet of the reaction tube 51 of the growth reaction container 5. The fifth valve is provided between the freezing tube 61 and the collection container 7.