Preparation method of cluster platinum powder

Abstract

The invention discloses a preparation method of cluster platinum powder, which comprises the following steps: firstly, weighing a dispersing agent, dissolving the dispersing agent in deionized water in a reaction kettle to serve as a reaction base solution, preparing a chloroplatinic acid solution, adding a proper amount of a stabilizer to serve as an oxidant solution, and preparing a corresponding amount of a reducing agent solution; dropwise adding an oxidant and a reducing agent solution into the reaction kettle according to a set flow rate for dropwise adding reaction; after the reaction is finished, solid and liquid phases are centrifugally separated, and a cluster platinum powder product is obtained after drying and crushing. The cluster platinum powder with different activities can be prepared by adjusting the pH value of the oxidizing agent, the stabilizing agent and the reaction temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of precious metal powder material preparation, and relates to a method for preparing clustered platinum powder, especially clustered platinum powder with controllable sintering activity. Background Art

[0002] Temperature sensors are essential components in the electronics industry. Platinum cluster powder, as the functional phase in temperature sensors, enables the fabrication of temperature sensors with high sensitivity and reliability. These sensors are widely used in a wide range of fields, including aviation, aerospace, computers, and the civilian market, and hold a crucial position in the electronics, information, and energy sectors. The continued development of high-end temperature sensors is placing higher demands on the performance of the conductive pastes used in temperature sensors. As a key raw material for temperature sensors, the superiority of parameters such as particle size, morphology, particle size distribution, tap density, and surface condition of platinum cluster powder significantly impacts performance.

[0003] Currently, methods for preparing clustered platinum powder include physical and chemical methods. The physical method is relatively difficult to implement and requires high sintering temperatures. The chemical method is the primary method used for large-scale production due to its low production cost and ease of control.

[0004] However, the sintering temperature of clustered platinum powder prepared by the current mainstream chemical method is basically uncontrollable, and cannot match the sintering temperature of the co-fired substrate in later applications. Summary of the Invention

[0005] In order to solve the above problems, the present invention addresses the shortcomings of existing cluster platinum powder preparation technologies and provides a method for preparing cluster platinum powder with simple preparation and adjustable sintering activity.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing clustered platinum powder, comprising the following steps:

[0007] Step 1: Weigh 1-10g of a dispersant and dissolve it in 1L of deionized water in a reactor as a reaction base liquid, prepare a chloroplatinic acid solution with a required pH, weigh 100g of a chloroplatinic acid solution with a platinum content and 3-5g of a stabilizer and dissolve them in 500mL of deionized water, use 40% by mass of a sodium hydroxide solution to adjust the solution pH to 2-12 as an oxidant solution, weigh 40-100g of a reducing agent and dissolve it in 500mL of deionized water as a reducing agent solution; wherein the mass of the dispersant is 1%-10% of the platinum in the chloroplatinic acid solution, and the mass ratio of the stabilizer to the platinum in the chloroplatinic acid solution is 1:20-100;

[0008] Step 2: Adjust the reaction temperature to 30-60°C, and add the oxidant solution and the reducing agent solution dropwise to the reactor at a flow rate of 5-30 mL / min for dropwise reaction;

[0009] Step 3: After the reaction is completed, wash with deionized water, separate the solid and liquid phases, dry at 60-120° C., and then crush to obtain about 100 grams of clustered platinum powder product.

[0010] Furthermore, the dispersant in step 1 is one of polyethylene glycol, methyl cellulose and gum arabic.

[0011] Furthermore, the stabilizer in step 1 is one of sodium edetate, aminotriacetic acid and hydroxyethylethylenediaminetriacetic acid.

[0012] Furthermore, the reducing agent in step 1 is one of hydrazine hydrate, hydrazine hydrochloride and sodium borohydride.

[0013] Furthermore, the reaction temperature in step 2 is adjusted by the temperature of the circulating water in the jacket of the reactor.

[0014] Furthermore, in step three, a vacuum drying oven is used for drying.

[0015] The advantages and positive effects of the present invention are as follows: the reduction system adopted in the present invention can significantly improve the yield of the powder; by adjusting the process parameters, the size of the clustered platinum powder can be controlled, and it has very good process stability, which can realize the large-scale production of clustered platinum powder, which can reach more than 5kg / batch.

[0016] The preparation method of the present invention has a simple and controllable process, low production cost, and is easy to implement on a large scale. Moreover, the method of the present invention can theoretically prepare platinum powder clusters with any sintering activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an SEM image of the platinum cluster powder prepared in Example 1;

[0018] Figure 2 This is an SEM image of the platinum cluster powder prepared in Example 2;

[0019] Figure 3 This is the SEM image of the clustered platinum powder prepared in Example 3. DETAILED DESCRIPTION

[0020] The present invention is described in detail below through examples, which are for the purpose of further illustrating the present invention and are not to be construed as limiting the scope of protection of the present invention. Example 1

[0021] This embodiment discloses a method for preparing clustered platinum powder, which includes the following steps.

[0022] Step 1: Weigh 1g of gum arabic and dissolve it in 1L of deionized water in a reactor as the reaction base liquid. The oxidant solution is 100g of chloroplatinic acid solution with a platinum content and 5g of sodium ethylenediaminetetraacetate dissolved in 500mL of deionized water. The pH of the solution is adjusted to 2 with 40% sodium hydroxide solution as the oxidant solution. Weigh 40g of sodium borohydride and dissolve it in 500mL of deionized water as the reducing agent solution.

[0023] Step 2: The reaction temperature is adjusted to 60° C. by circulating water in the jacket of the reactor. The oxidant and reducing agent solutions are added dropwise to the reactor at a flow rate of 15 mL / min for dropwise reaction.

[0024] Step 3: After the reaction is completed, the product is washed with deionized water, the solid and liquid phases are separated, and the product is dried in a vacuum drying oven at 105°C and crushed to obtain a clustered platinum powder product. The particle size of the prepared clustered platinum powder can be controlled by adjusting the sintering temperature.

[0025] Through SEM Figure 1 According to the analysis shown, 99.95 g of clustered platinum powder was obtained, and the particle size of the powder was 40 nm. Example 2

[0026] This embodiment discloses a method for preparing clustered platinum powder, which includes the following steps.

[0027] Step 1: Weigh 10g of polyethylene glycol and dissolve it in 1L of deionized water in the reactor as the reaction base liquid. The oxidant solution is 100g of chloroplatinic acid solution with a platinum content and 5g of aminotriacetic acid dissolved in 500mL of deionized water. The pH of the solution is adjusted to 12 with 40% sodium hydroxide solution as the oxidant solution. Weigh 100g of hydrazine hydrochloride and dissolve it in 500mL of deionized water as the reducing agent solution.

[0028] Step 2: The reaction temperature is adjusted to 30° C. by circulating water in the jacket of the reactor. The oxidant and reducing agent solutions are added dropwise to the reactor at a flow rate of 5 mL / min for dropwise reaction.

[0029] Step 3: After the reaction is completed, the product is washed with deionized water, the solid and liquid phases are separated, and the product is dried in a vacuum drying oven at 120°C and then crushed to obtain a clustered platinum powder product. The method of the present invention can adjust the particle size of the clustered platinum powder by controlling the preparation process parameters.

[0030] Through SEM Figure 2 According to the analysis shown, 99.93 g of clustered platinum powder was obtained, and the particle size of the powder was 70 nm. Example 3

[0031] This embodiment discloses a method for preparing clustered platinum powder, which includes the following steps.

[0032] Step 1: Weigh 2g of methylcellulose and dissolve it in 1L of deionized water in a reactor as a reaction base liquid; the oxidant solution is 100g of chloroplatinic acid solution with a platinum content and 3g of hydroxyethylethylenediaminetriacetic acid dissolved in 500mL of deionized water; 40% sodium hydroxide solution is used to adjust the solution pH to 8 as the oxidant solution; weigh 60g of hydrazine hydrate and dissolve it in 500mL of deionized water as the reducing agent solution.

[0033] Step 2: The reaction temperature is adjusted to 50° C. by circulating water in the jacket of the reactor. The oxidant and reducing agent solutions are added dropwise to the reactor at a flow rate of 30 mL / min for dropwise reaction.

[0034] Step 3: After the reaction is completed, the product is washed with deionized water to separate the solid and liquid phases, dried in a vacuum drying oven at 60° C., and then crushed to obtain a clustered platinum powder product.

[0035] Through SEM Figure 3 According to the analysis shown, 99.96 g of clustered platinum powder was obtained, and the particle size of the powder was 300 nm.

[0036] The technical content and features of the present invention are as shown above, but the protection scope of the present invention should not be limited to the contents described in the embodiments, but should include various replacements and modifications that do not deviate from the present invention and are covered by the claims of this patent application.

Claims

1. A method for preparing clustered platinum powder, characterized in that: Includes the following steps Step 1: Weigh 1-10g of a dispersant and dissolve it in 1L of deionized water in a reactor as a reaction base liquid; weigh 100g of a chloroplatinic acid solution with a platinum content and 3-5g of a stabilizer and dissolve them in 500mL of deionized water; use 40% by mass of a sodium hydroxide solution to adjust the solution pH to 2-12 as an oxidant solution; weigh 40-100g of a reducing agent and dissolve it in 500mL of deionized water as a reducing agent solution; wherein the mass of the dispersant is 1% to 10% of the platinum, and the mass ratio of the stabilizer to the platinum is 1:20-100; Step 2: Adjust the reaction temperature to 30-60°C, and add the oxidant solution and the reducing agent solution dropwise to the reactor at a flow rate of 5-30 mL / min; Step 3: After the reaction is completed, the product is washed with deionized water, the solid and liquid phases are separated, and the product is dried at 60-120° C. and then crushed to obtain clustered platinum powder.

2. The method for preparing a clustered platinum powder according to claim 1, characterized in that: The dispersant in step 1 is one of polyethylene glycol, methyl cellulose and gum arabic.

3. The method for preparing a clustered platinum powder according to claim 2, characterized in that: The stabilizer in step 1 is one or more of sodium edetate, aminotriacetic acid and hydroxyethylethylenediaminetriacetic acid.

4. The method for preparing a clustered platinum powder according to claim 3, characterized in that: The reducing agent in the step 1 is one of hydrazine hydrate, hydrazine hydrochloride and sodium borohydride.

5. The method for preparing a clustered platinum powder according to claim 4, characterized in that: The reaction temperature in step 2 is adjusted by the temperature of the circulating water in the jacket of the reactor.

6. The method for preparing a clustered platinum powder according to claim 5, characterized in that: In the step 3, a vacuum drying oven is used for drying.

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