In-situ Stress Determination in Thermally-grown Iron Oxide Scales using X-Ray Diffraction of Synchrotron Radiation

Abstract

The development of residual stress in the iron-oxide layers growing on phosphated α-Fe in the temperature range 375–450°C was investigated by in-situ X-ray diffraction of synchrotron radiation during oxide growth. As such, the stress state in the oxide layer for very short oxidation times which corresponds to low thickness of the oxide layer (≤1 µm) has been determined. The microstructural state of the oxide layers is first presented. Then a detailed study of the residual strains in the oxide layers is undertaken. Correlations between the residual stress measurements and the evolution of the microstructural state leads to a better understanding of the oxidation behaviour of phosphated α-Fe.