Oxidation behavior of HT9 steel in 700 °C – 900 °C steam

Oxidation behavior of the HT9 steel exposed to 700 degrees C -900 degrees C steam was investigated with gravimetry, X-ray diffraction and scanning electron microscopy. It was found that the oxidation kinetics of the HT9 steel followed the parabolic law. The mass gain increased with a decreasing temperature. The steam oxidation of the HT9 steel at 800 degrees C and 900 degrees C was selective. The oxides formed on the HT9-steel surface displayed a double-layer structure, consisting of an outer columnar Fe2O3 layer and an inner (Fe, Cr)(3)O-4 layer.