Abstract
	Electrochemical corrosion properties of lead-free solder alloys (Sn99Cu1; Sn95Sb3,5Cu1,5; Sn95Sb5; Sn95,5Ag3,8Cu0,7 and Sn96Ag4) and near eutectic Sn67Pb37 one are compared in the 0,1 mol/l KOH water solution at room temperature on the base of potentiodynamic polarization method (voltammetry).  These tin alloys were tested in the form of as-received wires and rods. Relative small differences were found out in corrosion potential values, passivation current densities and active peak width among these lead-free alloys. All these solders exhibit active–passive transition. There were registered significant differences between anodic polarization curves of lead-free and Sn-Pb solders. More anodic peaks were measured on the Sn63Pb37 solder, where transition to the transpassive region started at lower potential values in comparison with lead-free solders. Corrosion rate (according to current density and peak) was higher on Sb containing solders in the active state, on the other hand in the passive range the corrosion was higher for Sn-Pb one. The corrosion properties were not influenced by copper and silver in small quantity in the activity area, but in the transpassivity area they caused small peaks and current density increasing. The uniform corrosion was observed after potentiodynamic polarization tests. The results of chemical microanalysis of solders, including secondary phases and grain boundary areas are also given in the contribution. The main properties of tested tin solders (melting temperature range, surface stress, hardness, density) are compared too.