Oxidation of Iron in the Temperature Range of 260°–470°C

The kinetics of the oxidation of ingot iron in 19 mm O 2 has been studied over the temperature range of 260°–470°C. Both Fe 3 O 4 and α ‐ Fe 2 O 3 , were observed to be present at all temperatures and times. Initially Fe 3 O 4 grows to reach a value which becomes constant for some time and then starts to increase again. When the Fe 3 O 4 layer recommences growth there is also an increase in the over‐all oxidation rate. The rate constant for the early part of the oxidation is about half that of the latter part. In all cases the total oxidation rate is essentially parabolic.