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Preparation method of grain size controllable single dispersed nano silver powder

A nano-silver powder and monodisperse technology, which is applied in the field of preparation of monodisperse nano-silver powder, can solve the problems of small silver sol particle size, low silver concentration, and preparation of nano-silver powder, and achieve narrow particle size distribution, high purity, and good dispersion. Effect

Inactive Publication Date: 2005-10-26
SICHUAN UNIV
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

The photochemical reduction method is mainly to prepare nano-silver powder by reacting silver salt and iodide, and the particle size of the silver powder can be 10-30nm. The disadvantage is that the reaction speed is slow, especially for the preparation and production of large-scale samples such as kilograms.
[0003] At present, most of the liquid-phase chemical reduction methods prepare nano-silver powder. Due to insufficient control of the reaction process and process conditions, there are mainly two problems in the preparation of silver powder: one is that a specific method can only prepare a specific average The nano-silver powder of particle size cannot be prepared according to the particle size requirement, and the nano-silver powder of any required particle size can not be prepared; the second is that the solid monodisperse nano-silver powder cannot be separated from the nano-silver sol.
The silver sol prepared by this method has small particle size and good dispersibility, but the silver concentration is low, and in the process of preparing nano-silver powder from the silver sol, due to the use of high-speed centrifugation, the efficiency is low and the energy consumption is large, which is not conducive to industrialized production; in addition, This method can only prepare nano-silver powder with a single particle size

Method used

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  • Preparation method of grain size controllable single dispersed nano silver powder
  • Preparation method of grain size controllable single dispersed nano silver powder
  • Preparation method of grain size controllable single dispersed nano silver powder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Embodiment 1: as attached figure 1 , 2 , 7, prepare silver nitrate solution: take 34g silver nitrate, dissolve with 200mL deionized water; the preparation of reducing solution: sodium hypophosphite (NaH 2 PO 2 ·H 2 O) 14g, PVP 34g, sodium hexametaphosphate 4.3g, 10% H 2 SO 4 25mL, deionized water 1200mL; put the reducing solution in a stirred 3000mL three-necked bottle, and heat it in a water bath at 40°C; add the silver nitrate solution dropwise at 20 drops / min at a speed of 300r / min, after the dropwise addition is completed, Stirring was continued for 60 minutes; a silver sol was obtained. Place the prepared silver sol together with the three-necked bottle in an ultrasonic vessel, ultrasonically at 300W, while stirring at a speed of 1000r / min, add dropwise an ammonia solution with a mass fraction of 10% until the pH of the sol is 2; Set aside for 15 minutes, filter with 5 layers of slow-speed quantitative filter paper, soak the filter paper with ammonia water wi...

Embodiment 2

[0030] Embodiment 2: as attached figure 1 , 3 , 7, prepare silver nitrate solution: take 17g silver nitrate, dissolve with 200mL deionized water; the preparation of reducing solution: sodium hypophosphite (NaH 2 PO 2 ·H 2 O) 7g, PVP 15g, sodium hexametaphosphate 2.5g, 10% H 2 SO 4 10mL, deionized water 500mL; put the reducing solution in a stirred 1000mL three-necked flask, and heat it in a water bath at 50°C; add silver nitrate solution dropwise at 20 drops / min at a speed of 500r / min; silver sol is prepared. Place the prepared silver sol together with the three-necked bottle in an ultrasonic container, ultrasonically at 400W, while stirring at a speed of 600r / min, add dropwise an ammonia solution with a mass fraction of 2% until the pH of the solution is 3; Set aside for 15 minutes, filter with 4 layers of slow-speed quantitative filter paper, soak the filter paper with ammonia water with a mass fraction of 5%; passivate with a 1,2,3-benzotriazole solution with a mass f...

Embodiment 3

[0031] Embodiment 3: as attached figure 1 , 4 , 7 shown. The preparation of silver sol in this example is the same as the method described in Example 1. Ultrasonic the prepared silver sol at 500W, while stirring at 1000r / min, dropwise add ammonia solution with a mass fraction of 5%, until the pH of the sol is 4; let stand, and filter with 5 layers of slow quantitative filter paper , the filter paper was soaked with ammonia water with a mass fraction of 3%; passivated with a 1,2,3-benzotriazole solution with a mass fraction of 1%; washed 4 times with deionized water, and then washed with absolute ethanol and acetone Each was washed once, and dried under vacuum at 60°C. Gained silver powder has carried out TEM and XRD detection respectively, as Figure 4 , 7 As shown, the particles of the product are basically spherical, with good dispersion, an average particle size of 40nm, and high purity.

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Abstract

A process for preparing the dispersed silver nanopartjicles with controllable granularity includes such steps as preparing silver sol from solution of silver nitrate and reducer by reaction, high-speed stirring while adding pH value regulator under the active of ultrasonic waves, regulating pH=1-7 according to needed granularity, laying aside, filtering, passivating, washing and vacuum drying.

Description

technical field [0001] The invention relates to a method for preparing silver powder and a method for separating silver powder from silver sol, in particular to a method for preparing monodisperse nanometer silver powder with controllable particle size. Background technique [0002] At present, the commonly used methods for preparing silver powder at home and abroad are: thermal decomposition method, chemical reduction method, electrochemical method, sol-gel method, etc. The preparation of silver ultrafine powder mainly adopts liquid phase chemical reduction method, photochemical reduction method, laser gas phase method, laser ablation method and so on. The photochemical reduction method is mainly to prepare nano-silver powder by reacting silver salt and iodide, and the particle size of silver powder can be 10-30nm. The disadvantage is that the reaction speed is slow, especially for the preparation and production of large-scale samples such as kilograms. Physical methods su...

Claims

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Application Information

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IPC IPC(8): B22F9/24
Inventor 刘恒孙红刚尹光福
Owner SICHUAN UNIV
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