Silver-coated compact silver-nickel powder and preparation method thereof

Abstract

The application relates to the technical field of silver-coated nickel powder preparation, in particular to silver-coated nickel powder with compact silver layer and a preparation method, which comprises the following steps: adding nano silver ions, sodium dodecyl benzene sulfonate, deionized water and ethanol into a reaction kettle and stirring, then adding nickel powder after acid washing and sodium potassium tartrate and stirring, adding sodium hydroxide in the stirring process to obtain a nickel powder reduction liquid; adding silver nitrate and diethylene triamine into deionized water, uniformly stirring to obtain a silver source solution, heating the nickel powder reduction liquid in the reaction kettle, dropping the silver source solution into the nickel powder reduction liquid for chemical reaction, obtaining local reaction intensity and reaction consistency of each temperature measuring point in the reaction process, then obtaining reaction abnormality to obtain an expected reaction temperature, and cleaning to obtain wet powder of the silver-coated nickel powder after the reaction is completed, and the silver-coated nickel powder body with compact silver layer is prepared through drying. The application can improve the adjustment precision of the silver coating reaction temperature and guarantee the preparation quality of the silver-coated nickel powder body.

Description

Technical Field

[0001] This application relates to the field of silver-coated nickel powder preparation technology, specifically to a densely silver-coated nickel powder and its preparation method. Background Technology

[0002] Currently, the main methods for preparing silver-coated nickel powder include chemical methods, mixed ductile iron methods, and melt atomization methods. Among these, the chemical method, which involves a chemical reaction of silver coating causing the metallic element to settle on the substrate surface, has become the most common method due to its simplicity, ease of implementation, and high controllability. During the silver coating chemical reaction, the reaction temperature needs to be controlled in real time. Most existing technologies use PID controllers to regulate and control the reaction temperature to ensure the stability of the silver coating chemical reaction process and avoid affecting the dense and uniform deposition of Ag particles on Ni particles.

[0003] However, due to inconsistent reaction changes at different locations in the silver-coated reaction solution, and because the existing technology does not fully consider the inconsistent reaction change characteristics in the silver-coated reaction solution to accurately control and regulate the reaction temperature, the silver-coated reaction solution is prone to local overheating, which cannot effectively ensure the density of the silver coating of Ag particles on Ni particles. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this application is to provide a densely silver-coated nickel powder and its preparation method. The specific technical solution adopted is as follows:

[0005] This application provides a method for preparing densely coated silver-nickel powder, comprising the following steps:

[0006] Nano-silver ions, sodium dodecylbenzenesulfonate, deionized water, and ethanol were added to a reaction vessel and stirred. Then, acid-washed nickel powder and potassium sodium tartrate were added and stirred. Sodium hydroxide was added during the stirring process to obtain a nickel powder reducing solution. Silver nitrate and diethylenetriamine were added to deionized water and stirred evenly to obtain a silver source solution. The nickel powder reducing solution in the reaction vessel was heated, and the silver source solution was added dropwise to the nickel powder reducing solution to carry out a chemical reaction. The temperatures at multiple temperature measurement points were obtained.

[0007] High-temperature feature clusters are extracted by short-term temperature cluster analysis of each temperature measuring point. Based on the correlation between the short-term temperature of each temperature measuring point and the temperature in the high-temperature feature cluster, as well as the degree of temperature change of each temperature measuring point in a short period of time, the local reaction intensity of each temperature measuring point is obtained.

[0008] The consistency of the reaction at each sampling time is obtained by measuring the level of change and randomness of the local reaction intensity at each temperature measurement point. The reaction anomaly is obtained by combining the local reaction intensity. The expected reaction temperature at the current sampling time is obtained by using the change characteristics of the reaction anomaly. The reaction temperature of silver coating is adjusted. After the reaction is completed, the wet powder of silver-coated nickel powder is obtained by washing. After drying, a dense silver-coated nickel powder is obtained.

[0009] Preferably, 0.05 mg of nano silver ions, 5 g of sodium dodecylbenzenesulfonate, 3 kg of deionized water, and 300 g of ethanol are stirred in a reaction vessel for 20 min; the nickel powder pickling includes adding 1 kg of deionized water and 25 g of concentrated sulfuric acid to the reaction vessel, then adding 500 g of nickel powder, stirring at a speed of 400-500 r / min for 0.5-1 h, and then washing the nickel powder with deionized water to obtain the pickled nickel powder.

[0010] Preferably, during the subsequent addition of the pickled nickel powder and potassium sodium tartrate and stirring, the amount of pickled nickel powder is 500g and the amount of potassium sodium tartrate is 160g, the stirring time is 20-30min, and sodium hydroxide is added during the stirring process to adjust the pH value of the solution to 13.0-13.5.

[0011] Preferably, 190g of silver nitrate and 100g of diethylenetriamine are added to 3kg of deionized water and stirred to obtain a silver source solution. The nickel powder reducing solution is heated to 35-45℃, and the silver source solution is added dropwise to the nickel powder reducing solution at a rate of 3-6mL / min to carry out a chemical reaction.

[0012] Preferably, multiple neighboring acquisition times are extracted for each acquisition time, and the temperatures of each acquisition time and its neighboring acquisition times at each temperature measurement point are combined to form a local temperature set for each acquisition time at each temperature measurement point. The local temperature sets of each acquisition time at all temperature measurement points are clustered, and the cluster with the largest mean is taken as the high temperature feature cluster for each acquisition time.

[0013] Preferably, the process for obtaining the local reaction intensity at each temperature measurement point is as follows: In the formula, Let be the local reaction intensity at the j-th temperature measurement point at the t-th acquisition time. Let Jaccard similarity be the local temperature set of the j-th temperature measurement point at the t-th acquisition time and the high-temperature feature cluster. The degree of dispersion of all temperatures within the local temperature set of the j-th temperature measurement point at the t-th acquisition time.

[0014] Preferably, the process for obtaining the consistency of responses at each acquisition time is as follows: In the formula, Let be the consistency of the response at the t-th sampling time. It is an exponential function with the natural constant as its base. Let be the mean of the first-order difference sequence of the reaction feature sequence at the t-th acquisition time. Let be the information entropy of the reaction feature sequence at the t-th acquisition time, where the local reaction intensity at all temperature measurement points at each acquisition time is arranged in ascending order to form the reaction feature sequence at each acquisition time.

[0015] Preferably, the maximum value of the local reaction intensity at all temperature measurement points at each acquisition time is statistically analyzed, and the normalized result of the ratio of the maximum value to the reaction consistency is taken as the reaction anomaly at each acquisition time.

[0016] Preferably, the process of obtaining the desired reaction temperature at the current acquisition time is as follows: In the formula, The desired reaction temperature at the current sampling moment. and These are functions for finding the minimum and maximum values, respectively. and These are the minimum and maximum values ​​of the reaction temperature, respectively. This represents the actual reaction temperature at the current sampling moment. This represents the difference in reaction anomaly between the current acquisition time and the previous acquisition time, where the actual reaction temperature at the current acquisition time is the average temperature at all temperature measurement points at the current acquisition time.

[0017] This application also provides a dense silver-coated nickel powder, which is prepared by applying the steps of any one of the methods for preparing a dense silver-coated nickel powder.

[0018] As can be seen from the above, the silver-coated nickel powder with a dense silver layer and its preparation method provided in this application have at least the following beneficial effects:

[0019] This application uses the K-means clustering algorithm to extract high-temperature feature clusters of temperature changes in the silver-coated reaction solution, and uses these high-temperature feature clusters to accurately measure the intensity of the local reaction at all temperature measurement points in the silver-coated reaction solution. This more clearly reflects the intensity of the silver coating reaction in local areas of the silver-coated reaction solution, which helps to avoid the problem of excessively high local temperatures in the silver-coated reaction solution.

[0020] Furthermore, this application accurately measures the consistency of reaction intensity at different temperature points in the silver-coated reaction solution, and combines this with the maximum intensity of local reactions in the silver-coated reaction solution to accurately measure the abnormal characteristics of the reaction in the silver-coated reaction solution. This accurately reflects the abnormal conditions of the reaction in the silver-coated reaction solution, which is beneficial for the subsequent accurate control and adjustment of the reaction temperature.

[0021] This application fully considers the inconsistent reaction characteristics in the silver-coated reaction solution. By controlling the changes in the abnormal reaction characteristics in the silver-coated reaction solution, the reaction temperature in the silver-coated reaction process is accurately adjusted to avoid the problem of excessively high or low reaction temperature in the silver-coated reaction process. This improves the density and uniformity of Ag particles settling on Ni particles and ensures a good chemical reaction rate in the silver-coated reaction process. Attached Figure Description

[0022] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This application provides a flowchart of the steps involved in preparing a dense silver-coated nickel powder. Detailed Implementation

[0024] To further illustrate the technical means and effects adopted by this application to achieve the intended inventive purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a densely coated silver-nickel powder and its preparation method according to this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0025] Unless otherwise specified and limited, terms such as “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a circuit structure, article, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the article or device that includes said element. Furthermore, the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] The following description, in conjunction with the accompanying drawings, details the specific scheme of a densely silver-coated nickel powder and its preparation method provided in this application.

[0027] Please see Figure 1 It illustrates a flowchart of a method for preparing dense silver-coated nickel powder according to an embodiment of this application, including the following steps:

[0028] Example 1

[0029] Step 1: Add nano silver ions, sodium dodecylbenzenesulfonate, deionized water, and ethanol to a reaction vessel and stir. Then add acid-washed nickel powder and potassium sodium tartrate and stir. During stirring, add sodium hydroxide to obtain a nickel powder reducing solution. Add silver nitrate and diethylenetriamine to deionized water and stir evenly to obtain a silver source solution. Heat the nickel powder reducing solution in the reaction vessel and add the silver source solution dropwise to the nickel powder reducing solution to carry out a chemical reaction. Obtain the temperature at multiple temperature measurement points.

[0030] In this embodiment, the preparation method of the silver-coated nickel powder includes acid washing, activation, and silver coating. The specific preparation process is as follows:

[0031] (1) Pickling: Add 1 kg of deionized water to the reactor and slowly add 25 g of concentrated sulfuric acid to the deionized water. Then add 500 g of nickel powder, wherein the nickel powder is spherical nickel powder with a particle size of 1-5 μm. Stir for 0.5 h at a speed of 400. Remove the oxide layer on the surface of the nickel powder by pickling. Then wash the nickel powder with deionized water to obtain the pickled nickel powder.

[0032] (2) Activation: 0.05 mg of nano silver ions with a particle size of 1-5 μm, 5 g of sodium dodecylbenzenesulfonate, 3 kg of deionized water and 300 g of ethanol were added to the reaction vessel and stirred for 20 min. Then, 500 g of acid-washed nickel powder and 160 g of potassium sodium tartrate were added and stirred for 20 min. Sodium hydroxide was added during the stirring process to adjust the pH of the solution to 13.0 to obtain nickel powder reduction solution.

[0033] (3) Silver coating: 190g of silver nitrate and 100g of diethylenetriamine were added to 3kg of deionized water and stirred evenly to obtain a silver source solution; then, the nickel powder reducing solution in the reactor was heated to 35°C using an electric heater, and the silver source solution was added dropwise to the nickel powder reducing solution at a rate of 3mL / min to carry out a chemical reaction. In this embodiment, the preset initial reaction temperature was 40°C. During the chemical reaction, the reaction temperature needed to be adjusted and controlled by a PID controller. After the dropwise addition was completed, the reaction continued for 1 hour, stirring was stopped, and sedimentation was carried out. After washing, wet powder of silver-coated nickel powder was obtained; finally, the wet powder of silver-coated nickel powder was dried at 60-80°C for 2 hours to obtain a dense silver-coated nickel powder.

[0034] To ensure the stability of the silver-coated chemical reaction process and avoid affecting the dense and uniform deposition of Ag (silver) particles on Ni (nickel) particles, the reaction temperature needs to be accurately regulated and controlled. Therefore, a multi-point thermocouple is installed at the bottom of the reaction vessel to collect temperature data at multiple points in the silver-coated reaction solution. In this embodiment, the thermocouple's sampling frequency is 1Hz, and the number of sampling points is 16, obtaining temperature data at multiple sampling points at each sampling moment during the silver-coated reaction process.

[0035] Step 2: Extract high-temperature feature clusters by performing short-term temperature cluster analysis on each temperature measurement point. Based on the correlation between the short-term temperature of each temperature measurement point and the temperature in the high-temperature feature cluster, as well as the degree of temperature change at each temperature measurement point, obtain the local reaction intensity of each temperature measurement point.

[0036] Generally, inconsistent temperature changes occur at different temperature measurement points in a silver-coated reaction solution. Current technologies do not fully consider these inconsistent temperature characteristics to accurately control the reaction temperature, easily leading to localized overheating and affecting the density and uniformity of the silver coating. Therefore, it is necessary to fully explore the inconsistent temperature change characteristics of the reaction solution to accurately regulate and control the reaction temperature for silver coating.

[0037] To fully explore the inconsistent temperature change characteristics in the silver-coated reaction solution, multiple nearest neighbor acquisition times are extracted for local analysis. In this embodiment, preferably, the K acquisition times with the closest time interval to each acquisition time are recorded as the K nearest neighbor acquisition times for each acquisition time. The set of temperature data of each acquisition time and its K nearest neighbor acquisition times at each temperature measurement point is recorded as the local temperature set of each acquisition time at each temperature measurement point, where K is set to 60, reflecting the local temperature characteristics at different temperature measurement points in the silver-coated reaction solution.

[0038] Furthermore, the local temperature set at all temperature measurement points at each acquisition time is used as the input to the K-means clustering algorithm. The elbow rule is used to obtain the number of clusters in the K-means clustering algorithm. Each cluster is obtained through the K-means clustering algorithm, and the mean value of elements within each cluster is calculated. The cluster with the largest mean value is taken as the high temperature feature cluster at each acquisition time, reflecting the high temperature distribution in the silver-coated reaction solution in a local short period of time. The K-means clustering algorithm and the elbow rule are well-known techniques, and the specific process will not be described in detail.

[0039] Generally, since the chemical reaction of silver coating is an exothermic reaction, the greater the similarity between the local temperature set at the temperature measurement point in the silver coating reaction solution and the high temperature characteristic cluster, and the higher the dispersion of the temperature change at that temperature measurement point, the more likely a more intense local chemical reaction will occur at that temperature measurement point. This will cause the problem of excessively high local temperature in the silver coating reaction solution, thus failing to effectively ensure the density of the silver coating of Ag particles on Ni particles.

[0040] Based on the above analysis, the local reaction intensity at each temperature measurement point at each acquisition time is calculated: In the formula, Let be the local reaction intensity at the j-th temperature measurement point at the t-th acquisition time. Let Jaccard similarity be the local temperature set of the j-th temperature measurement point at the t-th acquisition time and the high-temperature feature cluster. Let represent the dispersion of all temperatures within the local temperature set of the j-th temperature measurement point at the t-th acquisition time. The dispersion can be measured using variance, standard deviation, or coefficient of variation; in this embodiment, the coefficient of variation is used.

[0041] Based on the above process, it can be understood that the intensity of the local reaction reflects the intensity of the local reaction at the temperature measuring point in the silver-coated reaction solution. The greater the intensity of the local reaction, the greater the intensity of the silver coating reaction in the local area of ​​the temperature measuring point. This results in the temperature at this temperature measuring point being higher than the temperature at other temperature measuring points in a short period of time, and the greater the dispersion of the temperature change at this temperature measuring point. In this case, the silver-coated reaction solution is more likely to cause the problem of excessively high local temperature, which affects the density of the silver coating of Ag particles on Ni particles.

[0042] Step 3: Obtain the consistency of the reaction at each sampling time based on the change level and random change degree of the local reaction intensity at each temperature measurement point. Combine the local reaction intensity to obtain the reaction anomaly. Use the change characteristics of the reaction anomaly to obtain the expected reaction temperature at the current sampling time, so as to adjust the reaction temperature of silver coating. After the reaction is completed, wash to obtain wet powder of silver-coated nickel powder, and dry to obtain dense silver-coated nickel powder.

[0043] Furthermore, the local reaction intensity obtained at all temperature measurement points at each acquisition time is arranged in ascending order. If the calculated local reaction intensity at different temperature measurement points is equal, in this embodiment, the equal local reaction intensity is arranged continuously to form a reaction characteristic sequence at each acquisition time, reflecting the characteristic changes in local reaction intensity at all temperature measurement points in the silver-coated reaction solution.

[0044] Generally, the greater the average difference in the intensity of the local reaction among all temperature measurement points in the silver-coated reaction solution, and the greater the disorder in the intensity of the local reaction among all temperature measurement points, the more it reflects the characteristic of inconsistent reaction intensity among different temperature measurement points in the silver-coated reaction solution. At this time, the different temperature measurement points in the silver-coated reaction solution exhibit unsteady and complex temperature changes, which is less conducive to the dense and uniform deposition of Ag particles on Ni particles.

[0045] Based on the above analysis, the consistency of response at each acquisition time is calculated: In the formula, Let be the consistency of the response at the t-th sampling time. It is an exponential function with the natural constant as its base. Let be the mean of the first-order difference sequence of the reaction feature sequence at the t-th acquisition time. Let be the information entropy of the reaction feature sequence at the t-th acquisition time.

[0046] The mean of all elements in the first-order difference sequence is used to characterize the average difference in the growth of local reaction intensity among all temperature measurement points in the reaction solution. The information entropy of all elements in the reaction characteristic sequence is used to characterize the random variation and disorder of local reaction intensity among all temperature measurement points. The product between the two is negatively mapped by an exponential function so that the calculation result is mapped to the range of (0,1). Therefore, the greater the average difference in the growth of local reaction intensity and the greater the disorder, the more inconsistent the reaction intensity is among different temperature measurement points in the silver-coated reaction solution, and the closer the calculated result of the reaction consistency is to 0.

[0047] Based on the above process, it can be understood that the reaction consistency reflects the consistency of the reaction intensity at different temperature measurement points in the silver-coated reaction solution. The smaller the reaction consistency, the more inconsistent the reaction intensity is between different temperature measurement points in the silver-coated reaction solution. At this time, the non-steady-state temperature changes at different temperature measurement points in the silver-coated reaction solution are more complex, which makes it more likely to cause local overheating in the silver-coated reaction solution, affecting the dense and uniform deposition of Ag particles on Ni particles.

[0048] Furthermore, due to the excessive intensity of local reactions in the silver-coated reaction solution and the inconsistency of reaction intensity at different temperature measurement points, there is a high possibility that the local temperature in the silver-coated reaction solution may be too high. Therefore, it is necessary to accurately control and regulate the reaction temperature to avoid poor uniformity of Ag particle deposition on Ni particles caused by excessively high reaction temperature.

[0049] Therefore, by combining the measured local reaction intensity and reaction consistency, the reaction anomaly in the silver-coated reaction solution is measured. Preferably, in this embodiment, the maximum value of the local reaction intensity at all temperature measurement points at each sampling time is counted. The maximum value of the local reaction intensity is used as the numerator, and the reaction consistency is used as the denominator. The normalized result of the range of the ratio of the numerator to the denominator is used as the reaction anomaly at each sampling time, reflecting the abnormal characteristics of the reaction in the silver-coated reaction solution. The greater the reaction anomaly, the more intense the local reaction in the silver-coated reaction solution is and the inconsistent reaction intensity at different temperature measurement points. It should be noted that, in this embodiment, to avoid the denominator being zero when calculating the ratio, a constant is added to the denominator to avoid the denominator being zero. The value range is (0, 0.01), and in this embodiment, the value is 0.001.

[0050] Generally, if the reaction anomaly increases at the current sampling time compared to the previous sampling time, it indicates that the abnormal characteristics of the reaction in the silver-coated reaction solution are more prominent at the current sampling time, and there is a higher possibility that the local temperature in the silver-coated reaction solution will be too high. At this time, the reaction temperature should be appropriately lowered to avoid the reaction temperature being too high and causing poor density and uniformity of Ag particles settling on Ni particles.

[0051] Conversely, if the abnormality of the reaction decreases at the current sampling time compared to the previous sampling time, it indicates that the abnormal characteristics of the reaction in the silver-coated reaction solution are weakened at the current sampling time. This suggests a lower probability of local overheating in the silver-coated reaction solution. In this case, the reaction temperature should be appropriately increased to avoid the phenomenon of excessively slow chemical reaction rate caused by excessively low reaction temperature.

[0052] Therefore, the expected reaction temperature at the current acquisition moment is calculated as follows: In the formula, The desired reaction temperature at the current sampling moment. and These are functions for finding the minimum and maximum values, respectively. and These are the minimum (35℃) and maximum (45℃) reaction temperatures, respectively. This represents the actual reaction temperature at the current sampling moment. This represents the difference in reaction anomalies between the current acquisition time and the previous acquisition time. The actual reaction temperature at the current acquisition time is the average temperature at all temperature measurement points at that time.

[0053] Specifically, the reaction temperature during the silver coating process is accurately adjusted by measuring the difference in reaction anomalies between the current acquisition time and the previous acquisition time. This avoids the problem of the reaction temperature being too high or too low during the silver coating process, improves the density and uniformity of Ag particles settling on Ni particles, and ensures a good chemical reaction rate during the silver coating process.

[0054] Furthermore, the reaction temperature of silver coating is controlled and regulated by a PID controller. The temperature error between the actual reaction temperature and the desired reaction temperature at the current acquisition time is input into the PID controller. The PID controller calculates the control signal based on the temperature error and transmits the control signal to the electric heater in the reactor. The electric heater in the reactor controls the reaction temperature of silver coating in real time, avoiding the problem of local overheating in the silver coating reaction solution.

[0055] Therefore, the reaction temperature is regulated and controlled by a PID controller during the silver coating chemical reaction process. After the reaction is completed, the powder is cleaned to obtain wet silver-coated nickel powder. Finally, the wet silver-coated nickel powder is dried at 60°C for 2 hours to obtain dense silver-coated nickel powder.

[0056] Example 2

[0057] In step 1 of Example 2, the stirring time was 0.7h under the condition of a rotation speed of 450 r / min during pickling. The oxide layer on the surface of the nickel powder was removed by pickling to obtain the pickled nickel powder.

[0058] During the activation process, 500g of pickled nickel powder and 160g of potassium sodium tartrate were added and stirred for 25 minutes. Sodium hydroxide was added during the stirring process to adjust the pH of the solution to 13.3, thus obtaining a nickel powder reduction solution.

[0059] During the silver coating process, an electric heater was used to heat the nickel powder reducing solution in the reactor to 40°C, and the silver source solution was added dropwise to the nickel powder reducing solution at a rate of 4 mL / min to carry out a chemical reaction. The resulting wet silver-coated nickel powder was dried at 70°C for 2 hours to obtain a dense silver-coated nickel powder.

[0060] It should be noted that in Example 2, the other processes in step 1, as well as steps 2 and 3, are exactly the same as in Example 1, and will not be repeated in this example.

[0061] Example 3

[0062] In step 1 of Example 3, the stirring time was 1 hour at a speed of 500 r / min during pickling, and then the nickel powder was washed out with deionized water to obtain the pickled nickel powder.

[0063] During the activation process, 500g of pickled nickel powder and 160g of potassium sodium tartrate were added and stirred for 30 minutes. Sodium hydroxide was added during the stirring process to adjust the pH of the solution to 13.5, thus obtaining a nickel powder reduction solution.

[0064] During the silver coating process, an electric heater was used to heat the nickel powder reducing solution in the reactor to 45°C, and the silver source solution was added dropwise to the nickel powder reducing solution at a rate of 6 mL / min to carry out a chemical reaction; the resulting wet silver-coated nickel powder was dried at 80°C for 2 hours to obtain a dense silver-coated nickel powder.

[0065] It should be noted that in Example 3, the other processes of step 1, as well as steps 2 and 3, are exactly the same as in Example 1, and will not be repeated in this example.

[0066] Based on the same inventive concept as the above method, this application embodiment also provides a silver-coated nickel powder with a dense silver layer, wherein the silver-coated nickel powder is prepared by applying the steps of any one of the silver-coated nickel powder preparation methods described above.

[0067] It is understood that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are possible or may be advantageous.

[0068] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0069] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the protection scope of this application.

Claims

1. A method for preparing densely silver-coated nickel powder, characterized in that, Includes the following steps: Nano-silver ions, sodium dodecylbenzenesulfonate, deionized water, and ethanol were added to a reaction vessel and stirred. Then, acid-washed nickel powder and potassium sodium tartrate were added and stirred. Sodium hydroxide was added during the stirring process to obtain a nickel powder reducing solution. Silver nitrate and diethylenetriamine were added to deionized water and stirred evenly to obtain a silver source solution. The nickel powder reducing solution in the reaction vessel was heated, and the silver source solution was added dropwise to the nickel powder reducing solution to carry out a chemical reaction. The temperatures at multiple temperature measurement points were obtained. High-temperature feature clusters are extracted by short-term temperature cluster analysis of each temperature measuring point. Based on the correlation between the short-term temperature of each temperature measuring point and the temperature in the high-temperature feature cluster, as well as the degree of temperature change of each temperature measuring point in a short period of time, the local reaction intensity of each temperature measuring point is obtained. The consistency of the reaction at each sampling time is obtained by measuring the level of change and random change of the local reaction intensity at each temperature measurement point. The reaction anomaly is obtained by combining the local reaction intensity. The expected reaction temperature at the current sampling time is obtained by using the change characteristics of the reaction anomaly. The reaction temperature of silver coating is adjusted. After the reaction is completed, the wet powder of silver-coated nickel powder is obtained by washing. After drying, a dense silver-coated nickel powder is obtained. In this process, multiple neighboring acquisition times are extracted from each acquisition time, and the temperatures of each acquisition time and its neighboring acquisition times at each temperature measurement point are combined to form a local temperature set at each temperature measurement point for each acquisition time. The local temperature sets at all temperature measurement points for each acquisition time are clustered, and the cluster with the largest mean is taken as the high temperature feature cluster for each acquisition time. The process for obtaining the local reaction intensity at each temperature measurement point is as follows: In the formula, Let be the local reaction intensity at the j-th temperature measurement point at the t-th acquisition time. Let Jaccard similarity be the local temperature set of the j-th temperature measurement point at the t-th acquisition time and the high-temperature feature cluster. The degree of dispersion of all temperatures within the local temperature set of the j-th temperature measurement point at the t-th acquisition time; The process for obtaining the consistency of responses at each acquisition time is as follows: In the formula, Let be the consistency of the response at the t-th sampling time. It is an exponential function with the natural constant as its base. Let be the mean of the first-order difference sequence of the reaction feature sequence at the t-th acquisition time. Let be the information entropy of the reaction feature sequence at the t-th acquisition time, where the local reaction intensity at all temperature measurement points at each acquisition time is arranged in ascending order to form the reaction feature sequence at each acquisition time. The maximum value of the local reaction intensity at all temperature measurement points at each acquisition time is statistically analyzed, and the normalized result of the ratio of the maximum value to the reaction consistency is taken as the reaction anomaly at each acquisition time. The process of obtaining the desired reaction temperature at the current acquisition moment is as follows: In the formula, The desired reaction temperature at the current sampling moment. and These are functions for finding the minimum and maximum values, respectively. and These are the minimum and maximum values ​​of the reaction temperature, respectively. This represents the actual reaction temperature at the current sampling moment. This represents the difference in reaction anomaly between the current acquisition time and the previous acquisition time, where the actual reaction temperature at the current acquisition time is the average temperature at all temperature measurement points at the current acquisition time.

2. The method for preparing densely silver-coated nickel powder as described in claim 1, characterized in that, The nano silver ions (0.05 mg), sodium dodecylbenzenesulfonate (5 g), deionized water (3 kg), and ethanol (300 g) were stirred in a reaction vessel for 20 min. The nickel powder pickling process involved adding 1 kg of deionized water and 25 g of concentrated sulfuric acid to the reaction vessel, followed by adding 500 g of nickel powder. The mixture was stirred at a speed of 400-500 r / min for 0.5-1 h, and then the nickel powder was washed out with deionized water to obtain the pickled nickel powder.

3. The method for preparing densely silver-coated nickel powder as described in claim 1, characterized in that, During the subsequent addition of pickled nickel powder and potassium sodium tartrate, the amount of pickled nickel powder is 500g and the amount of potassium sodium tartrate is 160g. The stirring time is 20-30 minutes, and sodium hydroxide is added during the stirring process to adjust the pH value of the solution to 13.0-13.

5.

4. The method for preparing densely silver-coated nickel powder as described in claim 1, characterized in that, 190g of silver nitrate and 100g of diethylenetriamine were added to 3kg of deionized water and stirred to obtain a silver source solution. The nickel powder reducing solution was heated to 35-45℃, and the silver source solution was added dropwise to the nickel powder reducing solution at a rate of 3-6mL / min to carry out a chemical reaction.

5. A dense silver-coated nickel powder, characterized in that, The silver-coated nickel powder is prepared by applying the steps of the silver-coated nickel powder preparation method as described in any one of claims 1-4.

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