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Method for preparing granularity-controllable narrow-distribution spherical easily-dispersible silver powder through radiation reduction

A narrow-distribution, easy-to-disperse technology, applied in the field of preparing spherical easily dispersible silver powder with controllable particle size narrow distribution, can solve the problems of small particle size, unsuitable for application, uneven surface, etc.

Inactive Publication Date: 2011-05-25
EAST CHINA UNIV OF SCI & TECH
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  • Application Information

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Problems solved by technology

Chinese patent (publication number CN 1227148A) discloses "a method for preparing silver powder using formate as a reducing agent and mixing with a special nozzle", but it requires special nozzle equipment, which is not conducive to large-scale production
Chinese patent (publication number CN 101462164A) discloses "a method for preparing silver powder with high tap density by chemical reduction", but its particle size distribution is still wide
Chinese patent (publication number CN 1709618A) discloses "a method for preparing nanometer, submicron and silver powder", but its particle size is mainly at the nanometer level, and the particle size is relatively small
Chinese patent (publication number CN 101347841A) discloses "a method for preparing silver powder with controllable particle size and high tap density by pouring method", which may cause adhesion between particles during production
Chinese patent (publication number CN 101569937A) discloses "a method for preparing silver powder by adding silver nitrate solution and reducing agent to hyperdispersant solution at the same time", Chinese patent (publication number CN 1387968A) discloses "a method by adjusting silver nitrate solution pH value preparation method of silver powder", however, from their specific introduction content, the distribution of silver powder particle size prepared by these methods is relatively wide
Chinese patent (publication number CN 101612670A) discloses "a method for preparing nano-scale silver powder by using 60Co-γ-ray irradiation reduction in aqueous solution". produce any environmental pollution, however, its particle size is 10-50 nanometers, the particle size is small, not suitable for application
However, the existing technology for preparing silver powder by irradiation reduction can only prepare nano-scale silver powder, which affects its application range.
[0003] As can be seen from the open literature, most of the current silver powder preparation techniques are chemical reduction methods, and their shortcomings are: the prepared silver powder has a wide particle size distribution, and the surface Not smooth, easy to bond between particles, poor dispersion, and more complicated to operate than the irradiation method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Example 1 Preparation of 1.0 μm Monodisperse Spherical Silver Powder by Radiation Reduction

[0021] (1) Preparation of 200nm seed silver powder: First, add dispersant PVP (0.1% by weight) and ammonia water to 50L of silver nitrate aqueous solution (5% by weight), and the amount of ammonia water should just dissolve the system; then hydrate 50L Hydrazine aqueous solution (0.1% by weight) was added dropwise to the silver ammonia solution, and reacted at 35°C for 1 hour; the resulting silver powder was washed with deionized water several times until the aqueous solution contained no organic impurities, and a clean monodisperse Spherical seed silver powder with a particle size of 200nm;

[0022] (2) Take 1Kg of 200nm seed silver powder obtained in step (1) and add it to 10L deionized water containing dispersant PVP (0.5% by weight) and active particle capture agent (0.5% by weight), stir and disperse; then add nitric acid Silver solution (5% by weight) 10L, feed nitrog...

Embodiment 2

[0024] Example 2 Preparation of 2.0 μm Monodisperse Spherical Silver Powder by Radiation Reduction

[0025] (1) (same as embodiment 1);

[0026] (2) Take 1Kg of seed silver powder obtained in step (1) and add it to 10L deionized water containing gelatin (1% by weight) and active particle capture agent (0.5% by weight), stir and disperse; then add silver nitrate solution (weight fraction Fraction 10%) 10L, blow nitrogen and exhaust oxygen for 5 minutes;

[0027] (3) Put in the radiation source cobalt-60, and carry out the radiation reduction reaction under stirring conditions. The radiation dose rate is 0.5 kGy / h, and the absorbed dose is 5 kGy; the silver powder after the radiation reduction reaction is washed with deionized water several times , until no organic impurities are contained in the aqueous solution, a monodisperse spherical silver powder of 2.0 μm is obtained.

Embodiment 3

[0028] Example 3 Preparation of 5.0 μm Monodisperse Spherical Silver Powder by Radiation Reduction

[0029] (1) Preparation of 400nm seed silver powder: First, add dispersant PVP (0.5% by weight) and ammonia water to 10L of silver nitrate (10% by weight) aqueous solution. The amount of ammonia water should just dissolve the system; then add 5L Hydrazine hydrate aqueous solution (1% by weight) was added dropwise to the silver ammonia solution, and reacted at 35°C for 1 hour; the obtained silver powder was washed with deionized water several times until the aqueous solution contained no organic impurities, and a clean single Dispersed spherical seed silver powder with a particle size of 400nm;

[0030] (2) Take 0.5Kg of 400nm seed silver powder obtained in step (1) and add it to 20L deionized aqueous solution containing dispersant polyethylene glycol (2% by weight) and active particle capture agent (0.5% by weight), and stir to disperse , then add 20L of silver nitrate solut...

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Abstract

The invention relates to the technical field of preparing powder materials through nuclear radiation technology, in particular to a method for preparing granularity-controllable narrow-distribution spherical easily-dispersible silver powder through radiation reduction. Chemically reduced small-granularity monodisperse silver powder is taken as a seed, silver ions are reduced under the gamma-ray radiation generated by radioactive substances, and the narrow-distribution, granularity-controllable, spherical and smooth-surface silver powder is obtained. The method comprises the following steps of: (1) preparing seed silver powder; (2) preparing raw materials for preparing the silver powder, and stirring and mixing; and (3) performing radiation reduction reaction by using cobalt-60 with stirring to obtain the narrow-distribution, granularity-controllable, spherical and smooth-surface silver powder, wherein the granularity is controlled to be 0.5-5mu m. The method has the advantages that: the seed silver powder is taken as a template, the narrow-distribution, granularity-controllable and spherical silver powder is generated through radiation reduction, the design and arbitrary mixing of electronic paste are facilitated, and the silver powder can meet various application requirements and has great promotion effect on development of electronic devices and products.

Description

technical field [0001] The invention relates to the technical field of preparing powder materials by nuclear radiation technology, in particular to a method for preparing spherical easily dispersible silver powder with controllable particle size and narrow distribution through radiation reduction. Background technique [0002] At present, silver powder is mostly made by chemical reduction method. Chinese patent (publication number CN 1227148A) discloses "a method for preparing silver powder by using formate as a reducing agent and mixing with a special nozzle", but it requires special nozzle equipment, which is not conducive to large-scale production. Chinese patent (publication number CN 101462164A) discloses "a method for preparing silver powder with high tap density by chemical reduction", but its particle size distribution is still relatively wide. Chinese patent (publication number CN 1709618A) discloses "a method for preparing nanometer, submicron and silver powder", ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24
Inventor 方斌葛学平刘华蓉杨存忠
Owner EAST CHINA UNIV OF SCI & TECH
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