Preparation of the micro-size flake silver powders by using a micro-jet reactor

Abstract

The micro-size flake silver powders were prepared through wet-chemical reduction method by using a micro-jet reactor. Herein ascorbic acid was used as a reducing agent, and sulfuric acid was used as a stabilizer. And the lauric acid was used as a dispersing agent to prevent particles’ agglomeration. The micro-jet reactor collides the two solutions together and uniformly mixes outside the reactor, to avoid the problem of clogging in the microchannel. The effects of dispersant addition and micro-jet flow rate on the morphology, particle size, and other parameters of silver powder is investigated in the present work. Interestingly, the addition of dispersant agent and stabilizer have a significant impact on the morphology and parameter of the silver particles. Under the conditions of micro-jet flow rate of 50 mL·min−1, sulfuric acid addition amount of 2%, and lauric acid addition amount of 0.8% by the weight of silver nitrate, a kind of flake silver powders with 4.40–4.70 μm can be prepared. The volume resistivity of the silver paste prepared from the obtained flake silver powders is in the range of 1.4–1.6 × 10−4 Ω·cm−1, which meets the application test requirements of conductive silver paste.

Optimizing Silver Paste Conductivity with Controlled Convection for Nanowrinkle Growth

“…The production of nanosilver particles poses technical challenges such as low preparation efficiency, susceptibility to agglomeration, or requiring high process conditions, while the preparation conditions for submicron and micron silver powders are relatively straightforward . In the specific preparation process of silver powder, the mixing of the reaction solution significantly impacts the consistency and process stability across different batches in quantity production. , The Lamer theory, encompassing nucleation and growth dynamics, has elucidated the concept of explosive nucleation, allowing for the preparation of silver powder with a narrow particle size distribution through rapid injection. Consequently, the speed of mixing in the reaction solution plays a pivotal role in the liquid-phase chemical method for silver powder preparation. , Achieving low silver powder content, high conductivity, and sintering submicron silver powder at low temperatures is a challenge.…”

“…10 In the specific preparation process of silver powder, the mixing of the reaction solution significantly impacts the consistency and process stability across different batches in quantity production. 11,12 The Lamer theory, encompassing nucleation and growth dynamics, has elucidated the concept of explosive nucleation, allowing for the preparation of silver powder with a narrow particle size distribution through rapid injection. Consequently, the speed of mixing in the reaction solution plays a pivotal role in the liquid-phase chemical method for silver powder preparation.…”