REAL-TIME OBSERVATIONS OF THE OXIDATION OF MILD-STEEL AT HIGH-TEMPERATURE BY NEUTRON-DIFFRACTION

The in situ characterization of the phase composition of iron oxides, ''scale,'' that form on low carbon steel during oxidation at elevated temperatures was carried out using the neutron diffraction technique. Growths in the intensities of diffraction peaks from the crystal plane s of the various oxides (FexO, Fe3O4, and Fe2O3) were monitored on-lin e. The volume fractions of the oxides in the scale were calculated on the basis of ideal structure factors and measured relative intensities of diffraction peaks. These were selected from a small region of the diffraction pattern. Calculated volume fractions of these oxides in th e scale layer were in agreement with the area fractions obtained from scanning electron microscopy (SEM) analysis of the scale.