Method for preparing superfine spherical silver powder for barium-titanate-based semiconductor ceramic ohmic electrode slurry

An electrode slurry and semiconductor technology, which is applied in the field of industrialized preparation of ultrafine silver powder for barium titanate-based ceramic ohmic electrode slurry, can solve the problem that the process is complicated and cannot meet the performance requirements of barium titanate-based semiconductor ceramic ohmic electrode slurry , the particle size of ultra-fine silver powder is too large, and the effect of high purity, excellent ohmic contact performance and wide firing temperature range is achieved.

Active Publication Date: 2011-10-12
HEFEI SHENGDA ELECTRONIC TECH IND CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The invention patent "Surface Treatment Method of Ultra-fine Silver Powder" published by the China Intellectual Property Office on January 4, 2006, publication number 1234492C, the ultra-fine silver powder produced by this invention has too large particle size and complicated process operation, which cannot meet the requirements of barium titanate-based semiconductors. Performance requirements of ceramic ohmic electrode paste

Method used

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  • Method for preparing superfine spherical silver powder for barium-titanate-based semiconductor ceramic ohmic electrode slurry
  • Method for preparing superfine spherical silver powder for barium-titanate-based semiconductor ceramic ohmic electrode slurry
  • Method for preparing superfine spherical silver powder for barium-titanate-based semiconductor ceramic ohmic electrode slurry

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Embodiment 1

[0025] Example 1: A preparation method of ultrafine spherical silver powder for barium titanate-based semiconductor ceramic ohmic electrode slurry

[0026] Weigh 90gAgNO 3 Dissolve in 300ml deionized water, place in a 2000ml beaker with stirring device; add 1.3g polymer resin, and AgNO 3 Solution emulsification; dropwise adding 10wt% Na at room temperature and high rotation speed 2 CO 3 to pH8-12; add 1.2-2.0 times the amount of reducing agent, and carry out the reduction reaction for 1.5 hours. During the reaction, add 20ml of alcohol for defoaming; adjust the stirring speed to 80r / min, keep warm, and form ultra-fine silver powder particle aggregates. The reaction was kept for 2.0 hours; the natural sedimentation method was used to wash the reacted precipitate 6 times according to the volume ratio of powder to deionized water of 1:10, and then dried at 50°C. The ultrafine silver powder with complete sphericity is obtained, the specific surface area is 7.94m2 / g, the dispers...

Embodiment 2

[0029] Example 2: A preparation method of ultrafine spherical silver powder for barium titanate-based semiconductor ceramic ohmic electrode slurry

[0030] Weigh 90gAgNO 3 Dissolve in 300ml deionized water, place in a 2000ml beaker with stirring device; add 1.3g polymer resin, and AgNO 3 Solution emulsification; dropwise adding 10wt% Na at room temperature and high rotation speed 2 CO 3 to pH8-12; add 0.2g polymer surfactant, add 1.2-2.0 times the amount of reducing agent, and carry out the reduction reaction for 1.5h; adjust the stirring speed to 80r / min, keep warm, and form ultra-fine silver powder particle aggregates, react Insulate for 2.0 hours; use the natural sedimentation method to wash the reacted precipitate 6 times according to the volume ratio of powder to deionized water of 1:10, and dry it at 60°C. Obtain ultra-fine silver powder with good sphericity, and the specific surface area is 8.14m 2 / g, good dispersibility, narrow particle size distribution range, pu...

Embodiment 3

[0032] Example 3: A preparation method of ultrafine spherical silver powder for barium titanate-based semiconductor ceramic ohmic electrode slurry

[0033] Weigh 90gAgNO 3 Dissolve in 300ml deionized water, place in a 2000ml beaker with stirring device; add 1.3g polymer resin, and AgNO 3 Solution emulsification; dropwise adding 10wt% Na at room temperature and high rotation speed 2 CO 3to pH8-12; add 1.0g long carbon chain organic reagent, add 1.2-2.0 times the amount of reducing agent, and carry out the reduction reaction for 1.5h; adjust the stirring speed to 80r / min, keep warm, form ultrafine silver powder particle aggregates, and react Insulate for 2.0 hours; use the natural sedimentation method to wash the reacted precipitate 6 times according to the volume ratio of powder to deionized water of 1:10, and dry it at 60°C. Obtain ultra-fine silver powder with good sphericity, and the specific surface area is 7.95m 2 / g, good dispersibility, narrow particle size distribut...

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Abstract

The invention discloses a method for preparing superfine spherical silver powder for barium-titanate-based semiconductor ceramic ohmic electrode slurry, which comprises the following steps of: preparing silver nitrate solution, adding a polymer dispersant with high-speed stirring, and regulating the pH value of the silver nitrate solution to be between 8 and 12; and adding another polymer dispersant, a reducing agent and an antifoaming agent in turn, washing by using deionized water, and drying to obtain a finished product. By skillfully utilizing the change of high and low stirring rotating speeds and adding stirring heat preservation, superfine silver powder particle aggregate with an organic surface is formed, and the settling speed of the silver powder is greatly increased; an organicreagent with a dispersion function, and a polymer surfactant are selected as the antifoaming agent, so that the dispersion function and an antifoaming function are enhanced simultaneously; suitable polymer dispersants, reducing agent, antifoaming agent and alcohol are selected, so that the superfine silver powder with high purity and complete sphericity is prepared, and the barium-titanate-based semiconductor ceramic ohmic electrode slurry prepared from the superfine silver powder has high adhesion and ohmic contact performance and a wide firing temperature range; and the preparation method is nontoxic, low in cost and environment-friendly.

Description

technical field [0001] The invention relates to metallic silver powder for electronic paste, and is particularly suitable for the industrialized preparation of ultrafine silver powder for barium titanate-based ceramic ohmic electrode paste, and the whole reaction process achieves environmentally friendly production. Background technique [0002] Barium titanate-based ceramics is a semiconductor ceramic material. Eliminate the surface barrier of barium titanate-based ceramics, so that a good ohmic contact is formed between the electrode layer and the substrate, and its various electrical properties can be reflected. To eliminate the surface barrier of barium titanate-based semiconductor ceramics, it is necessary to form an ohmic electrode layer on its surface. The electrode layer is usually printed with ohmic electrode paste through a screen printing process, and then sintered at a temperature above 500°C. Ohmic electrode paste with excellent performance needs to be prepared...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24
Inventor 谭晶
Owner HEFEI SHENGDA ELECTRONIC TECH IND CO LTD
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