微量の硫黄を添加した耐熱合金の高温酸化挙動

抄録

High-temperature oxidation behavior of Fe-20Cr-4Al alloys with 3, 7, 35, 53, 104, 171, 185, 491, 1300 and 6300ppm of sulfur was studied for 18.0ks in oxygen at 1273, 1373, 1473, 1573 and 1673K by mass change measurements, observation of surface appearance of the alloys, X-ray diffraction, scanning electron microscopy and electron probe microanalysis. Mass change of the alloys increased roughly with increasing oxidation temperature. However, the mass changes of the alloys with 7, 35 and 53ppm of sulfur at 1473K, with 7, 35, 53 and 104ppm of sulfur at 1573K and with 7ppm of sulfur at 1673K showed negative values. This fact was in good agreement with spalling of the oxide on the alloys. On the other hand, mass changes of the alloys with more than 171ppm of sulfur decreased with increasing content of sulfur at 1673K. The oxide adherence of these alloys with more than 7ppm of sulfur may be attributed to the size and shape of chromium sulfide particles at the oxide/alloy interface.