| 摘要 |
PURPOSE:To obtain silver powder for a conductive adhesive agent having a low concn. of residual ion and the narrow width of a grain size distribution in a method for adding a reducing agent to an aq. silver salt soln. and precipitating silver powder by using the specific aq. silver salt soln. CONSTITUTION:The reducing agent is added to the aq. ammonical silver nitrate soln. directly or after adding water soluble nitrate thereto to precipitate silver powder. The silver powder is thus obtd. The aq. ammonical silver nitrate soln. refers to the soln. prepd. by adding about >=30pts.wt. 30% ammonia water by 100pts.wt. silver nitrate to silver nitrate soln. The precipitated silver powder has the small width of the grain size distribution and has good reproducibility thereof even if the silver salt is reduced by hydrazine according to the above-mentioned method. Harmful residual ions are not contained in the precipitated silver powder if caustic alkali is not used and therefore a rinsing stage, etc. which are post-stage are made simpler.
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