Chronological study of the oxidation of phosphated α-iron

In the present work, the morphological evolution of the iron-oxide layers growing at 400 °C on α-Fe and phosphated α-Fe in artificial air at 1 atm is investigated. The oxidation kinetics of α-Fe and phosphated α-Fe are firstly presented for various oxidation times. Then a detailed chronological study is undertaken of the microstructural states in the different stages of the complex oxidation kinetics. Correlations are established between the morphology of the oxides layers and the successive parabolic oxidation stages. It is shown that the phosphate conversion layers seem to modify the growth mechanisms of the oxides.