Highly crystalline silver powder and process for production of the same

A manufacturing method and high crystallization technology, applied in metal processing equipment, transportation and packaging, etc., can solve the problems of low crystallinity, insufficient elements, unstable shape of silver particles, etc., and achieve stable crystallite size, large crystallite size, etc. The effect of particle size

Inactive Publication Date: 2008-07-09
MITSUI MINING & SMELTING CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Moreover, it clearly records that the crystallite diameter of the silver particles obtained here is in the range of 400 to 600 Ȧ, and when it is lower than 400 Ȧ, the crystallinity is low as the silver grains for high-temperature firing conductor paste, and when it is greater than 600 Ȧ When Å, the shape of silver particles is unstable
In addition, although there is a bulk density of silver particles at 5g / cm2 in Patent Document 5 3 Above, the specific surface area of ​​silver particles is 0.15m 2 / g The following description, but because the two elements are based on the premise of the relationship with the original particle size, and because there is no description of the particle size at all, the document is not sufficient to limit the elements of the powder

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] Preparation of the first aqueous solution: 1.0 g of gelatin, 50 g of silver nitrate, and 26.4 g of nitric acid were added to 250 g of pure water, and the solution was heated to 50° C. while stirring to dissolve it.

[0058] Preparation of the second aqueous solution: 26.4 g of erythorbic acid as a reducing agent and 4.2 g of DL-malic acid as a water-soluble organic acid were dissolved in 250 g of pure water to prepare a solution.

[0059] Reduction precipitation of highly crystalline silver powder: To the above-mentioned first aqueous solution at a liquid temperature of 50° C., slowly add the second aqueous solution over 30 minutes. After the mixing and addition of the first aqueous solution and the second aqueous solution was terminated, the mixture was stirred for 5 minutes to grow precipitated silver particles.

[0060] Filtration of high crystalline silver powder: After 5 minutes of stirring, leave it as it is to precipitate the generated silver powder, discard the ...

Embodiment 2

[0062] Preparation of the first aqueous solution: the same as in Example 1, and its description is omitted to avoid duplication of description.

[0063] Preparation of the second aqueous solution: 26.4 g of erythorbic acid as a reducing agent and 3.6 g of citric acid as a water-soluble organic acid were dissolved in 250 g of pure water to prepare a solution.

[0064] Reduction precipitation of highly crystalline silver powder: To the above-mentioned first aqueous solution at a liquid temperature of 50° C., slowly add the second aqueous solution over 30 minutes. After the 1st aqueous solution and the 2nd aqueous solution were mixed and added, it stirred for 5 minutes, and precipitated silver particle was made to grow.

[0065] Filtration of high crystalline silver powder: After 5 minutes of stirring, leave it as it is to precipitate the generated silver powder, discard the supernatant, filter and wash in the usual way to obtain high crystalline silver powder. The powder proper...

Embodiment 3

[0067] Preparation of the first aqueous solution: 3.3 g of gelatin, 55 g of silver nitrate, and 27 g of nitric acid were added to 550 g of pure water, and the solution was heated to 50° C. while stirring to dissolve it.

[0068] Preparation of the second aqueous solution: 28.1 g of erythorbic acid as a reducing agent and 4.47 g of DL-malic acid as a water-soluble organic acid were dissolved in 250 g of pure water to prepare a solution.

[0069] Reduction precipitation of highly crystalline silver powder: To the above-mentioned first aqueous solution at a liquid temperature of 50° C., slowly add the second aqueous solution over 30 minutes. After the 1st aqueous solution and the 2nd aqueous solution were mixed and added, it stirred for 5 minutes, and precipitated silver particle was made to grow.

[0070] Filtration of high crystalline silver powder: After 5 minutes of stirring, leave it as it is to precipitate the generated silver powder, discard the supernatant, filter and was...

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Abstract

The invention aims at providing a process for the production of highly crystalline silver powder which comprises silver particles falling within the fine particle region and has an excellent particle size distribution and highly crystalline silver powder obtained by the process. The aim is attained by a process for the production of highly crystalline silver powder which is characterized by preparing the first aqueous solution containing gelatin, silver nitrate and nitric acid and having a temperature of 45 to 55 C and the second aqueous solution containing erythorbic acid and / or ascorbic acid and a water-soluble organic acid, adding the second aqueous solution mildly to the first aqueous solution, stirring the mixed solution after the completion of the addition to form silver particles through particle growth, allowing the resulting system to stand to settle the silver particles, removing the supernatant, and then subjecting the remainder to filtration and washing to recover the silver particles.

Description

technical field [0001] The present invention relates to silver powder, especially high crystallization silver powder and the manufacturing method of the high crystallization silver powder. Background technique [0002] Conventionally, highly crystalline (large crystallite size) silver powder has excellent thermal shrinkage resistance during firing, and has been processed into silver ink or silver paste and widely used. For example, in addition to simultaneous firing with ceramic substrates to form circuits at relatively high temperatures, there are also various applications such as wiring circuits for printed wiring boards, via hole filling, and adhesives for component mounting. The use of mixing and curing resin components. In particular, silver powders used in silver inks or silver pastes used to form wiring such as circuits or electrodes are required to have excellent thermal shrinkage resistance during firing from the viewpoint of improving the shape accuracy of conduct...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24B22F1/00
CPCB22F1/0044B22F9/24B22F1/07B22F1/00
Inventor 藤本卓佐佐木卓也吉丸克彦
Owner MITSUI MINING & SMELTING CO LTD
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