In-situ observation and evaluation of silver precipitation behavior in borosilicate glass

Abstract

Applying voltage to alkali-containing glass, doped with silver ions by the solid-state ion-exchange method, yields silver precipitates inside the glass. We attempted in-situ observation of the precipitation phenomena to elucidate the silver precipitation mechanisms, where the direction of the voltage application was rotated 90 deg. to increase the precipitation area compared to that of our previous method. The results show that the shape of the precipitate changed from clumpy to dendritic as the applied voltage increased. The shape of the precipitate, predicted by the dielectric breakdown model, implied that the higher the precipitation probability (i.e., the higher the frequency of a silver ion to encounter with the precipitate), the more branches the precipitate formed. In addition, the un-doped, silver-doped, and silver-precipitated areas inside the glass were modeled as electrical resistances to predict the growth behavior of the precipitated areas.