  Understanding elemental corrosion currents and visualizing corroding
topographies provide a detailed insight into corrosion mechanisms at the
nano-scale. Here, we develop a strategy to understand the elemental
composition, corrosion resistivity and local stability of passive materials.
Specifically, we utilize a pulse voltammetry approach in a novel
electrochemical AFM cell and complement this data by real-time dissolution
currents based on spectro-electrochemical online analysis in an ICP-MS flow
cell. We study the oxide properties and their protective behaviour, when formed
under different applied potentials using alloy 600 as model sample. Both AFM
and ICP-MS data show that passive films formed on alloy 600 at around +0.3 to
+0.4~V in neutral 1 mM NaCl solution are most stable during anodic corrosion at
+1.0~V, while AFM further demonstrates that local dissolution occurs,
indicating locally varying defect levels in the passive film. In combination of
both techniques, our approach provide real-time elementally resolved and
localized information of passive film quality under corrosive conditions, and
it may prove useful for other corroding materials.
