3. Characterization techniques

As we have just seen, the corrosion systems that develop on archaeological ferrous objects, even if they are made up of phases of the same nature as the systems formed over shorter times, are different from the latter, particularly in terms of the thickness of the layers of corrosion products. These great thicknesses mean that we need to know how these layers control corrosion mechanisms and kinetics, and whether these are the same factors as those at shorter times. Characterizing the composition, structure and texture of these layers (linked to transport phenomena, local reactivity, phase conductivity, etc.) is therefore of the utmost importance. To achieve this, a set of complementary techniques is required, enabling us to understand the corrosion system from the nanometric to the micrometric scale.