Abstract
A new bath for the electroless plating of silver has been investigated. Optimum bath composition and plating conditions were: silver nitrate 8.8×10-3M, ethylenediamine 5.4×10-2M, Rochelle salt 3.5×10-2M, 3, 5-diiodotyrosine 4×10-5M, pH10.0 and temperature 35°C. The most important additives for bath stability were 3-iodotyrosine and 3, 5-diiodotyrosine.
Bath life was strongly affected by pH. The effect of pH on the oxidation of reducing solutions without silver nitrate was examined by measuring the rest potential of silver and platinum electrodes. The coexistence of intermediates with the active hydrogen in the process of the oxidation of the reducing agent was predicted, and measurements of the UV absorption spectra of the reducing solution suggested that pH influences the structure of ionic species in the solution.
