Metal oxide systems studied by analytical electron microscopy

SUMMARY Detailed analysis of thin oxide films is providing a better understanding of the mechanisms of oxidation and corrosion. The analytical electron microscope used to study thin layers on iron-chromium alloys has shown that even after oxidation times as short as 10 min at 600°C the ratio of iron to chromium in the surface oxide will be different from that in the underlying alloy and discrete nodules may well have a higher iron content than the protective film in which they are growing. Progressive changes in different morphological features of the oxide films grown at varying times and temperatures can be followed by micro-probe analysis in EMMA 4. Results obtained from the oxidation in air of iron with 10% and iron with 20% added chromium are presented.