A method for preparing silver-platinum alloy powder

Abstract

The application discloses a preparation method of silver-platinum alloy powder, and aims at preparing silver-platinum alloy powder with adjustable silver-platinum proportion, adjustable particle size and high dispersibility. First, deionized water is added into a reaction kettle, and a dispersing agent is added to be fully dissolved as a reaction bottom solution; silver nitrate, platinum nitrate and a stabilizer are weighed and dissolved in the deionized water to be used as an oxidizing agent solution; a reducing agent is weighed and dissolved in the deionized water to be used as a reducing agent solution; then, silver seed crystals are added into the reaction bottom solution, and the oxidizing agent solution and the reducing agent solution are added dropwise to be reacted; after the reaction is completed, secondary reaction is carried out by heating; finally, the silver-platinum alloy powder is obtained through washing with deionized water and ethanol, separating solid and liquid phases, drying and crushing. According to the application, by changing the adding amount of the seed crystals and adjusting the dropwise adding flow rate, silver-platinum alloy powder with different platinum content, adjustable particle size and high dispersibility can be prepared.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of noble metal powder material preparation, and relates to a preparation method of silver-platinum alloy powder. BACKGROUND

[0002] A sensor is the most basic component in the electronic industry, and silver-platinum alloy powder is used as a functional phase in the sensor. The prepared sensor has high sensitivity and high reliability, and is widely used in many fields such as aviation, aerospace, electronic computers and civilian markets, and occupies an extremely important position in the fields of electronics, information and energy. Especially with the further development of high-end sensor devices, higher requirements are put forward for the performance indicators of the conductive paste in the sensor.

[0003] Silver-platinum alloy powder is a key raw material for sensors, and the superiority or inferiority of parameters such as particle size, morphology, particle size distribution, tap density and surface state will have an important influence on the performance.

[0004] At present, the preparation methods of silver-platinum alloy powder include physical methods and chemical methods. The physical method is relatively difficult to realize and has high preparation cost, and the chemical method is mainly used in large-scale production due to its low production cost and easy control. However, the silver-platinum alloy powder prepared by the mainstream chemical method has poor alloying degree, and the high surface silver content leads to easy volatilization and transfer during the sintering process of the paste. SUMMARY

[0005] In order to solve the above problems, the present application provides a preparation method of silver-platinum alloy powder with simple preparation, high surface platinum content, adjustable particle size and good dispersity, so as to prepare silver-platinum alloy powder with adjustable silver-platinum ratio, adjustable particle size and high dispersity.

[0006] The technical scheme adopted by the present application to solve the technical problems is as follows: a preparation method of silver-platinum alloy powder, comprising the following steps:

[0007] Step one, 1L of deionized water is added to a reaction kettle, and 10-30g of a dispersant is fully dissolved as a reaction bottom solution; 110-140g of silver nitrate, 17.5-100g of platinum nitrate reagent and 10-15g of a stabilizer are weighed and dissolved in 300mL of deionized water as an oxidizing agent solution; 120-140g of a reducing agent is weighed and dissolved in 300mL of deionized water as a reducing agent solution; wherein the mass of the dispersant is 5-20% of the mass of the silver nitrate, and the molar ratio of the stabilizer to the platinum nitrate is 1:1-5;

[0008] Step two, silver seed crystal is added into the reaction bottom solution of the reaction kettle, the volume ratio of the silver seed crystal to the mass of silver powder in the oxidant solution is 1:5-100, the particle size of the silver platinum alloy powder is adjusted by the amount of the seed crystal, the oxidant solution and the reducing agent solution are added dropwise into the reaction kettle at a flow rate of 15 mL / min to carry out dropwise reaction, the dropwise reaction temperature is 35-55 DEG C;

[0009] Step three, after the dropwise reaction is completed, the reaction kettle is heated to 50-60 DEG C to carry out secondary reaction, the secondary reaction time is controlled by the different platinum content, the reaction temperature is adjusted by the circulating water temperature in the reaction kettle jacket; wherein the ratio of the secondary reaction time (min) to the platinum content (w%) in the oxidant solution is 1:0.5-5;

[0010] Step four, after the silver platinum alloy powder reaction is completed, the silver platinum alloy powder product with a particle size distribution D50 of 480-650 nm and a platinum content of 9.8-29.6% is obtained by washing with deionized water and ethanol, separating the solid-liquid phase, drying at 45 DEG C-70 DEG C and crushing.

[0011] The reaction bottom solution in step one of the silver platinum alloy powder preparation method is obtained by dissolving 10-30 g of dispersant in 1 L of deionized water, the oxidant solution is obtained by dissolving 110-140 g of silver nitrate, 17.5-100 g of platinum nitrate and 10-15 g of stabilizer in 300 mL of deionized water, and the reducing agent solution is obtained by dissolving 120-140 g of reducing agent in 300 mL of deionized water; 5-10 mL of silver seed crystal is added in step two; the secondary reaction time is 20-40 min in step three; and 100 g of silver platinum alloy is obtained in step four.

[0012] Further, the dispersant is one or more of polyvinylpyrrolidone K60, methyl cellulose and gum arabic.

[0013] Further, the stabilizer is one or more of ethylenediaminetetraacetic acid sodium, amino triacetic acid and hydroxyethyl ethylenediamine triacetic acid.

[0014] Further, the reducing agent is one or more of L-ascorbic acid, hydrazine hydrate and citric acid.

[0015] Further, the reaction temperature in steps two and three is adjusted by the circulating water temperature in the reaction kettle jacket.

[0016] Further, the powder is dried in a vacuum drying oven in step four.

[0017] The beneficial effects of the present application are:

[0018] 1. The method of the present application can prepare products with adjustable silver platinum ratio;

[0019] 2. The method improves the proportion of platinum on the outer layer of the silver-platinum alloy powder by secondary reaction, and improves the sintering temperature of the powder;

[0020] 3. The particle size of the silver-platinum alloy powder can be controlled by adding the amount of crystal seeds, and the particle size of the prepared silver-platinum alloy powder is simple to control;

[0021] 4. The method has very good process stability through the control of the preparation process parameters, and can realize the large-scale production of the silver-platinum alloy powder, and can achieve more than 5 kg / batch;

[0022] 5. The silver-platinum alloy powder can be prepared by adjusting the process parameters, the particle size distribution of the obtained silver-platinum alloy powder product is narrow, the dispersity is good, the preparation method process is simple and controllable, the production cost is low, and large-scale production is easy to realize. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 SEM image of the silver-platinum alloy powder prepared in Example 1;

[0024] Figure 2 SEM image of the silver-platinum alloy powder prepared in Example 2;

[0025] Figure 3 SEM image of the silver-platinum alloy powder prepared in Example 3;

[0026] Figure 4 SEM image of the silver-platinum alloy powder prepared in Example 4. DETAILED DESCRIPTION

[0027] The application will be specifically described below by means of the drawings and examples, and the description of the examples is not used to limit the protection scope of the application. Example 1

[0028] The silver-platinum alloy powder preparation method provided in the embodiment is prepared by the following steps.

[0029] Step one, 1L of deionized water is added to the reaction kettle, 30g of polyvinylpyrrolidone K60 is fully dissolved as the reaction bottom solution, 110g of silver nitrate, 52g of platinum nitrate and 10g of sodium ethylenediaminetetraacetate are dissolved in 300mL of deionized water as an oxidizing agent solution, and 100g of L-ascorbic acid is dissolved in 300mL of deionized water as a reducing agent solution.

[0030] Step two, 10mL of silver crystal seeds is added to the reaction kettle, and the oxidizing agent and reducing agent solutions are added to the reaction kettle at a flow rate of 15mL / min for dropwise reaction, the dropwise reaction temperature is 35℃, and the reaction temperature is adjusted by the circulating water in the reaction kettle jacket.

[0031] Step three, after the end of the drop reaction, the reaction kettle is heated to 60℃, and the second reaction is carried out for 40 min, and the reaction temperature is adjusted by circulating water in the jacket of the reaction kettle.

[0032] Step four, after the reaction of the silver-platinum alloy powder is completed, the reaction kettle is washed with deionized water and ethanol, and the solid-liquid phase is separated. After drying at 45℃, the product of the silver-platinum alloy powder with a particle size distribution D50 of 480-650nm / 300-650nm and a platinum content of 9.8-29.6% is obtained.

[0033] Step four, after the reaction is completed, the reaction kettle is washed with deionized water and ethanol, and the solid-liquid phase is separated. After drying the powder in a vacuum drying oven, the final silver-platinum alloy powder product is obtained by air crushing.

[0034] The present application can realize the controllable preparation of silver-platinum alloy powder by adjusting the process parameters, and the obtained silver-platinum alloy powder product has narrow particle size distribution and good dispersibility. The preparation method has simple and controllable process, low production cost, and is easy to realize large-scale production.

[0035] The obtained silver-platinum alloy powder 99.6g is analyzed by SEM as shown in Figure 1 The particle size distribution D50 is 480nm, and the platinum content is 29.6%. Example 2

[0036] The silver-platinum alloy powder preparation method proposed in this embodiment is prepared by the following steps.

[0037] Step one, 1L of deionized water is added to the reaction kettle, 20g of methyl cellulose is added and dissolved as the reaction bottom solution, 120g of silver nitrate, 30g of platinum nitrate and 12g of amino triacetate are dissolved in 300mL of deionized water as the oxidizing agent solution, and 20g of hydrazine hydrate is dissolved in 300mL of deionized water as the reducing agent solution.

[0038] Step two, 8mL of silver seed is added to the reaction kettle, and the oxidizing agent and reducing agent solution is added to the reaction kettle at a flow rate of 15mL / min for dropwise reaction. The dropwise reaction temperature is 55℃, and the reaction temperature is adjusted by circulating water in the jacket of the reaction kettle.

[0039] Step three, after the end of the drop reaction, the reaction kettle is heated to 50℃, and the second reaction is carried out for 20 min, and the reaction temperature is adjusted by circulating water in the jacket of the reaction kettle.

[0040] Step four, after the reaction is completed, the reaction kettle is washed with deionized water and ethanol, and the solid-liquid phase is separated. After drying the powder in a vacuum drying oven at 60℃, the final silver-platinum alloy powder product is obtained by air crushing.

[0041] The obtained silver-platinum alloy powder 99.8g is analyzed by SEM as shown inFigure 2 The analysis shows that the particle size distribution D50 is 520 nm, and the platinum content is 9.8%. Example 3

[0042] The preparation method of the silver-platinum alloy powder provided in this example is prepared by the following steps.

[0043] Step one, 1L of deionized water is added to the reaction kettle, 10g of gum arabic is fully dissolved as the reaction bottom solution, 140g of silver nitrate, 17.5g of platinum nitrate, and 15g of hydroxyethyl ethylenediamine triacetate are dissolved in 300mL of deionized water as an oxidizing agent solution, and 140g of citric acid is dissolved in 300mL of deionized water as a reducing agent solution.

[0044] Step two, 5mL of silver seed is added to the reaction kettle, and the oxidizing agent and reducing agent solution are added to the reaction kettle at a flow rate of 15mL / min for dropwise addition reaction, the dropwise addition reaction temperature is 40℃, and the reaction temperature is adjusted by circulating water in the reaction kettle jacket.

[0045] Step three, after the dropwise addition reaction is completed, the reaction kettle is heated to 55℃, and a secondary reaction is carried out for 30min, and the reaction temperature is adjusted by circulating water in the reaction kettle jacket.

[0046] The obtained silver-platinum alloy powder is 99.1g, and the SEM analysis shows that the particle size distribution D50 is 650nm, and the platinum content is 9.9%. Figure 3

[0047] The preparation method of the silver-platinum alloy powder provided in this example is prepared by the following steps.

[0048] Step one, 10L of deionized water is added to the reaction kettle, 300g of polyvinylpyrrolidone K60 is fully dissolved as the reaction bottom solution, 1400g of silver nitrate, 100g of platinum nitrate, and 150g of ethylenediaminetetraacetic acid sodium are dissolved in 2900mL of deionized water as an oxidizing agent solution, and 1200g of L-ascorbic acid is dissolved in 2800mL of deionized water as a reducing agent solution.

[0049] Step two, 60mL of silver seed is added to the reaction kettle, and the oxidizing agent and reducing agent solution are added to the reaction kettle at a flow rate of 100mL / min for dropwise addition reaction.

[0050] Step three, after the dropwise addition reaction is completed, the reaction kettle is heated to 60℃, and a secondary reaction is carried out for 20min.

[0051] Step four, after the reaction is completed, it is washed with deionized water and ethanol, the solid-liquid phase is separated, and the final silver-platinum alloy powder product is obtained after drying and airflow breaking.

[0052] ​The obtained silver-platinum alloy powder 998.3 g, analyzed by SEM as shown in Figure 4 the particle size distribution D50 is 500 nm, and the platinum content is 9.8%.

[0053] The technical content and features of the present application are as shown above, but the scope of protection of the present application should not be limited to the content expressed by the examples, but should include various alternatives and modifications without departing from the present application, and is covered by the claims of the present patent application.

Claims

1. A method for preparing silver-platinum alloy powder, characterized in that: Includes the following steps Step 1: Add 1L of deionized water to the reaction vessel and dissolve 10-30g of dispersant thoroughly to prepare the reaction base solution; weigh 110-140g of silver nitrate, 17.5-100g of platinum nitrate, and 10-15g of stabilizer and dissolve them in 300mL of deionized water to prepare the oxidizing agent solution; weigh 120-140g of reducing agent and dissolve them in 300mL of deionized water to prepare the reducing agent solution; wherein the dispersant is one or more of polyvinylpyrrolidone K60, methylcellulose, and gum arabic, and its mass is 5%-20% of that of silver nitrate; the stabilizer is one or more of sodium ethylenediaminetetraacetate, aminotriacetic acid, and hydroxyethylethylenediaminetriacetic acid, and its molar ratio with platinum nitrate is 1:1-5; and the reducing agent is one or more of L-ascorbic acid and citric acid. Step 2: Add 5-10 mL of silver seed crystals to the reaction base solution. The volume ratio of the silver seed crystals to the mass ratio of silver powder in the oxidant solution is 1:5-100. Add the oxidant solution and reducing agent solution to the reaction vessel at a flow rate of 15 mL / min to carry out the drop reaction. Adjust the temperature of the drop reaction by circulating water in the reaction vessel jacket to 35-55℃. Step 3: After the dropwise addition reaction is completed, the temperature of the reactor is raised to 50-60°C by adjusting the temperature of the circulating water in the reactor jacket, and a secondary reaction is carried out for 20-40 minutes; the ratio of the secondary reaction time to the platinum content in the oxidant solution is 1:0.5-5. Step 4: After the reaction is complete, wash with deionized water and ethanol respectively to separate the solid and liquid phases. Dry the powder in a vacuum drying oven at 45℃~70℃ and then crush it to obtain the silver-platinum alloy powder product.

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