A 70% Sn-30% Zn layer is deposited from a neutral non-cyanide bath. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) show, that it is composed of Sn and Zn phases. By use of an electrochemical quartz crystal microbalance (EQCM), the plating current efficiency is determined. When the plated sample is exposed to a 0.5 M Na2SO4 (pH 3.6) Solution at open circuit potential (OCP), the EQCM measures the corrosion rate. The open circuit potential shows that the Zn dissolution reaction is the major reaction Occurring at OCP. A linear potential scanning experiment shows that the anodic polarization current of this system is rather small in a wide range of potentials until it reaches the anodic dissolution potential of pure Sn in the same solution.