Role of ClO~- _4 in breakdown of tin passivity in NaOH solutions

摘要

The anodic behaviour of a tin electrode in NaOH solutions containing different concen- trations of NaClO_4 was studied by employing potentiodynamic, potential transient under constant current density methods and complemented with scanning electron microscopy (SEM). In perchlorate-free NaOH solutions, the E/i response exhibits active/passive transi- tion. The active region involves two anodic peaks corresponding to the formation of Sn(Ⅱ) and Sn(Ⅳ) species respectively. The permanent passive layer is duplex and consists of SnO and SnO_2.