Fe_3Al多孔材料预氧化性能研究

Research on the Preoxidation Performance of Fe_3 Al Porous Materials

以Cr改性的Fe3Al预合金粉末为原料,采用粉末冶金方法制备Fe3Al多孔材料,研究氧化温度、时间、降温速度对Fe3Al多孔材料氧化膜性能的影响。结果表明:Fe3Al多孔材料的氧化增重随温度的升高而增大,氧化动力学遵循四次方规律,在800℃的大气中氧化9h,氧化膜已完全将烧结颈覆盖,晶粒细小;随着温度的升高和时间的延长,晶粒变得粗大;900℃氧化5h,膜层已出现裂纹;而降温速度对氧化增重的影响不大,也没有出现由于热膨胀不匹配而产生的裂纹。

Fe3 Al porous materials were fabricated by the powder metallurgy method with Cr-modified Fe3 Al pre-alloy powder as starting material.The effects of oxidation temperature and time,and cooling rate on properties of oxidation scales of Fe3 Al porous materials were researched.The results show that oxidation mass gain is increased with the temperature increasing.Oxidation kinetics of Fe3 Al porous materials follows the fourth power rules.The oxidation scales with small grain size have completely covered the sintered neck of Fe3 Al porous materials after 9 h oxidation in atmosphere at 800℃.The grains become coarse with higher temperature and longer time.The cracks have appeared on oxidation scales after 5 h oxidation in atmosphere at 900℃.Cooling rate has little effect on mass gain and the cracks do not appear due to the unmatched thermal expansion coefficient.