抄録
The present authors observed oxide films and scales produced on the surface layers of Fe-Si-Cr system alloys (about 1 to 7% Si, 5 to 19% Cr), heated in air at high temperatures (700° to 1200°C), using the transmission electron diffraction method, the X-ray diffraction method and a metallurgical microscope. It was verified that 3 to 7% Si-Cr-Fe system alloys are covered mainly with Cr2O3 or α-(Cr, Fe)2O3 crystal films in the early stages of oxidation at 700°C and 1000°C (Table 1). It has already been reported that amorphous SiO2 films can be detected on the surface of 1 to 6% Si-Fe system alloys at 700° to 1000°C as a result of oxidation, but this kind of oxide film has not been observed on the surfaces of 1 to 4% Si-Cr-Fe system alloys heated in air under the above conditions. The present studies also clarified experimentally that the heat-resisting films of Fe-Si-Cr system alloys oxidized in air at 1100° and 1200°C for 7 hours are composed of fine Cr2O3 crystals (Table 1).
