Fe-Si-Al系合金の高温における酸化膜およびスケール

抄録

The present authors observed the oxide films and scales produced on the surface layers of Fe-Si-Al alloys (ca. 1-6% Si-1-7% Al) by using the transmission electron diffraction, X-ray diffraction and metallugical microscopic methods, when the alloys came into contact with air at 700°-1200°C. And thereby the authors detected the special heatresisting films consisting of amorphous SiO₂ or fine Al₂O₃ crystals which were formed on the surfaces of Fe-Si-Al alloys in the earliest stage of oxidation at 700°C and 1000°C (Table 2). It was also clarified by X-ray diffraction measurments that fine α-Al₂O₃ crystals are formed on the surfaces of ca. 6% Al-Si-Fe alloys (FSA 3 and 6), and moreover, that ca. 6% Si-Al-Fe alloy is covered with SiO₂ crystals at 1100°C. Besides iron oxides, the X-ray diffraction patterns of the oxide scales produced on the Fe-Si-Al alloys at 1200°C illustrate the existence of Fe₂SiO₄ crystal layers. The eutectic point of Fe₂SiO₄ and FeO phases is 1170°C, therefore it should be reasonable to consider that the heatresisting nature of these alloys fall remarkably at 1200°C.