Potentiostatic Electrodeposition of Au-Sn Alloys from a Non-Cyanide Bath for Soldering: Influence of Reagents Concentrations

Abstract

This work presents an extensive study of a non-cyanide Au-Sn bath to obtain potentiostatically deposited Au-Sn alloys. In addition, Au-Sn bath speciation was studied through a program for chemical equilibrium simulation (CHEAQS Pro) and the electrochemical mechanisms were investigated using Cyclic Voltammetry (CV). Also, Rutherford Backscattering Spectroscopy (RBS) was used to determine the deposits characteristics and composition. Some recipes using different concentrations of ammonium citrate, SnCl2 and Na2SO3, and L-ascorbic acid presented the formation of colloidal gold during the electrodeposition processes. The incorporation of tin in the deposits obtained varied from 2 to 16 atomic % (at%).