Selected area visualization by FIB-milling for corrosion-microstructure analysis with submicron resolution

We report the successful use of focussed ion beam (FIB) milling of trenches in a material of complex microstructure in order to visualize a selected area (32×32 μm) for further multi-analysis with submicron resolution. This capability is demonstrated for a Zn–5 wt% Al coating Galfan™ on steel. The very same eutectic surface area was analyzed by three complementary and independent techniques providing consistent information on the lateral distribution of morphology and elemental composition (scanning electron microscopy with x-ray microanalysis, SEM/EDS), topography and Volta potential (scanning Kelvin probe force microscopy, SKPFM) and oxide composition (confocal Raman microspectroscopy, CRM). The approach enables a straightforward way to explore the interplay between microstructure and local corrosion of metallic materials.