A preparation method of silver micropowder capable of precisely controlling specific surface area

Abstract

The invention relates to a silver micro-powder preparation method capable of accurately controlling specific surface area. The method comprises the following steps: (1) preparing a silver nitrate solution at a concentration of 0.5 to 1.5 mol / L; (2) dropwise adding a sodium carbonate solution at the concentration of 1.2 to 1.6 mol / L to the silver nitrate solution, and regulating the pH to be 10 to 13; (3) preparing a mixed solution at the mass fraction of 0.05 to 0.1% through polyvinyl alcohol and gelatin; (4) uniformly mixing the mixed solution and the silver nitrate solution; (5) dropwise adding a triethanolamine solution to the silver nitrate solution to obtain silver micro-powder paste; (6) washing, filtering and drying the prepared silver micro-powder paste. According to the method, different mixing ratio of a dispersing agent and a protecting agent in the reduction reaction of the silver powder is controlled to realize the accurate control of the specific surface area of the silver micro-powder; the process of the method is simple, and the production cost is low; the method is applicable to industrial mass production; the prepared silver micro-powder is widely applicable to intermediate-temperature sintering and high-temperature sintering of electronic paste.

Description

technical field [0001] The invention relates to a preparation method of silver micropowder, in particular to a preparation method of silver micropowder capable of precisely controlling the specific surface area. Background technique [0002] Metal ultrafine powder itself has superior catalytic properties, magnetic properties, electrical properties, etc., so it has more and more applications in aerospace, electronics, chemical medicine, powder metallurgy, etc. Among them, silver micropowder has good electrical and thermal conductivity, and is widely used in the electronics industry as a raw material for the production of components such as piezoelectric ceramics, capacitors, and potentiometers, as well as conductive pastes and conductive inks. With the development of the electronics industry, the demand for conductive paste is increasing, and the performance requirements for conductive paste are getting higher and higher. [0003] The silver paste used in electronic componen...

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Problems solved by technology

Song Xiangang et al [Song Xiangang, Lou Hongtao, Liang Binglian. Research on factors affecting specific surface area in the preparation process of silver micropowder [J]. Electronic Components and Materials, 2013, 32(10), 29-32.], disclosed a preparation process of silver micropowder In the study of the factors affecting the specific surface area, the liquid-phase chemical reduction method was used, with hydrazine hydrate as the reducing agent, polyvinylpyrrolidone (PVP) and gum arabic as the dispersant, and sodium carbonate as the pH regulator, and a silver with a high specific surface area was prepared. Micropowder, to study the influence of factors such as the amount of PVP dispersant, silver mass concentration, sodium carbonate dosage, reaction temperature and co-current pressure on the specific surface area of ​​silver micropowder, but this research has not yet been mass-produced

[0004] At present, the sintered silver powder produced in China generally has problems such as poor sintering activity, large sintering shrinkage and poor compactness.

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