Studies on Glass Silvering Solution

Abstract

The author studied on silver plating solution which was composed of a ammonical water solution of silver nitrate and a water solution of rochelle salt. The results were briefly summerised as follows:1. Ammonia water, when used in excess to dissolve a precipitate of Ag2O, was found to hinder the reduction of silver, while in the case of insufficient quantity, a white precipitate of silver tartrate, which results the loss of available silver, was produced. Just quantity of ammonia water to dissolve Ag2O was necessary to obtained a good mirror.2. Relative quanities of silver nitrate and rochelle salt were found to be changeable in some range in a mirror making, that is, a solution of low content of silver nitrate and high content of rochelle salt or vice versa showed the same results, but below 0.0014gr or of silver nitrate per cm2 of glass surface good mirror could not be made.3. The reduction of silver was accelerated by rising of temperature of increase of concentration of the solution.4. The addition of silver nitrate to the water solution of rochelle salt coursed the increase of the reducing action of the latter, and the more quantity of silver nitrate the more increase was found.The boiling hours of the rochelle salt solution which contained silver nitrate effectad upon the reducing action of it, and the boiling for an hour was found to be most effective to obtained a powerful solution.The increase of the reducing power of a rochelle salt solution which contained silver nitrate was found to be owed to neither silver ion or colloidal silver, nor NO3 radical or acidic substance in the solution.