Fe-Si-Cr系合金の高温酸化膜およびスケール

抄録

The present authors made observation on oxide films and scales produced on the surface layers of Fe-Si-Cr system alloys (ca. 1∼7%Si, 5∼19%Cr), when they came into contact with air at high temperatures (700∼1200°C) using the transmission electron diffraction, X-ray diffraction and a metallurgical microscope. Thereby the authors verified that ca. 3∼7%Si-Cr-Fe system alloys are covered mainly with Cr₂O₃ or α-(Cr,Fe)₂O₃ crystal films in the earliest stage of oxidation at 700° and 1000°C (Table 1). The authors have already reported that amorphous SiO₂ films were detected on the surfaces of ca. 1∼6%Si-Fe system alloys at 700∼1000°C oxidation, but this kind of oxide films has not been observed on the surfaces of ca. 1∼4%Si-Cr-Fe system alloys heated in air under the same 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 hrs are composed of fine Cr₂O₃ crystals (Table 1).