Electrodeposition of lead–tin alloy from methanesulphonate bath containing organic surfactants

The article discusses the process of electrodeposition of lead-tin alloy (tin content in the deposit up to 10–12 wt %) from methanesulfonate electrolytes. A composition was proposed of organic additives to the electrolyte providing attainment of high quality microcrystalline coatings with the alloy of predetermined composition at relatively low content of Sn 2+ in the solution. It has been shown that the tin content in the deposit increases at an increase in current density and decrease in the electrolyte temperature. For production of anti-frictional Pb-Sn alloys with the tin content of about 10% the electrolysis should be performed at a current density of about 4 A/dm 2 and the temperature not exceeding 25°C. The effect of a decrease in the discharge rate of the Sn 2+ ions into the alloy at deposition from electrolyte without organic additives was discovered, that is stipulated by deceleration of crystallization stage of tin on foreign substrate. When the alloy is deposited from electrolyte containing a composition of organic additives, the effect of super-polarization of discharge of Sn 2+ ions is reduced.