Electroless silver plating on Pb-based glass frits by a one-step activation method without stannum and palladium

In this paper, a new activation method—taking ethylene glycol as reducing agent for the formation of metallic silver (Ag0) from silver ions (Ag+)—has been introduced to form silver nuclei on Pb-based glass frits for silver paste. Electroless silver plating on glass frits is successfully realized by adding the activated glass frits into two kinds of electroless plating baths. The result shows that the silver particles with an average grain size around 100 nm are well distributed on the glass frits. Compared with the traditional electroless plating method, this process avoids the interference of chloride ions which may cause AgC1 precipitation as well as the tin ions which are harmful to human health. Furthermore, roughening treatment is not involved in the activation, so composition change will not happen to glass frits and front silver paste in the follow-up process.