Flux-encased resilient solder preforms and process for the preparation thereof

摘要

Relatively resilient flux encasings for solder preforms are obtained when a mixture of 5 to 30 wt. % potassium silicate having a molar ratio of K2O:SiO2 ranging from 1:2.5 to 1:4.5, 0.5 to 10 wt. % concentrated phosphoric acid, 0.1 to 5 wt. % boric acid and 0 to 10 wt. % finely divided silicon dioxide, with the remainder water, is used as the binder.