Passive layer investigation on tin and tin solder alloys

The present work investigates the passive film formation and properties on tin and tin solder alloys in weakly acidic nitrate solution by using conventional electrochemical methods as well as electrochemical impedance spectroscopy and Mott-Schottky analysis. It is observed that the influence of the main alloying elements, antimony and copper, positively influences the formation and properties of native oxide films on the respective alloys. If the oxide film is anodically formed, the process can be interpreted as a high-field mechanism. In this case, antimony, as well as copper, increases the electron conductivity of the anodic formed layers analogous to the transparent conducting oxide layers (e.g., ATO layers).