Laser Raman spectroscopy: A technique for rapid characterisation of oxide scale layers

A laser Raman microscope was used to collect spectra from individual phase regions visible in a polished cross-section of a thick oxide scale grown on a steel at high temperature. The technique was shown to be capable of unambiguously distinguishing the three iron oxides, FeO, Fe₃O₄, and Fe₂O₃. The standard spectra were then used to analyse the phases within thin (<10 μm) millscales developed on the steel during the hot rolling stage of steel strip production. Poor quality surface appearance was demonstrated to be associated with the development of fragmentary Fe₂O₃ regions.