The Cyclic Oxidation Behaviors of Fe_3 (Al, Cr, Zr) and Fe_3 (Al, Cr, Nb) Intermetallic Compound at High Temperature

The cyclic oxidation behaviors of Fe-28Al-5Cr-O. 1Zr (at%) and Fe-28Al5Cr-O.5Nb (at%) alloys have been investigated in air at high temperature. The results show that the distinctive whisker-like oxides were formed on the surface of Zr-containing Fe3 Al based alloy after 500 hrs. cyclic oxidation at 800℃ and 1000℃. The results also indicate that the addition of small amount of Zr to Fe3 Al based alloy can improve its adherence strength between the oxides and metal substrate and is beneficial to the oxidation resistance. However, for the Nb-containing Fe3 Al based alloy, porous convoluted oxides were formed after 350 hrs. cyclic oxidation at 1000℃, and this type of oxides didn't not contribute to the oxidation resistance.

Fe_3（Al，Cr，Zr）和Fe_3（Al，Cr，Nb）金属间化合物的高温氧化行为

用循环氧化法研究了Ｆｅ－２８Ａｌ－５Ｃｒ－０．１Ｚｒ（ａｔ％）和Ｆｅ－２８Ａｌ－５Ｃｒ－０．５Ｎｂ（ａｔ％）金属间化合物的高温氧化行为．结果表明，含Ｚｒ的Ｆｅ３（Ａｌ，Ｃｒ）金属间化合物在８００℃、１０００℃、５００ｈ循环氧化后形成一个独特的晶须状氧化物层，微量Ｚｒ能增加氧化物层与基体金属的粘附性，从而提高了该合金的高温抗氧化性能．而含Ｎｂ的Ｆｅ３（Ａｌ，Ｃｒ）金属间化合物在１０００℃、３５０ｈ循环氧化后形成多孔的卷绕状形貌，对Ｆｅ３（Ａｌ，Ｃｒ）金属间化合物的高温抗氧化性没有改善．

几种Ni-Cr-Al墓低偏析高温合金的抗氧化性能研究

在１０００～１１００℃之间，对三种Ｃｒ、Ａｌ含量及微量元素Ｓ、Ｚｒ含量不同的Ｎｉ－Ｃｒ－Ａｌ基合金进行了恒温和循环氧化实验。结果表明，高Ｃｒ（１６Ｗｔ％），低Ａｌ（３．５Ｗｔ％）、Ｓ（０．００５ｗｔ％）含量，且不含Ｚｒ的合金其氧化膜层主要由连续致密的Ｃｒ２Ｏ３外氧化层和树根状Ａｌ２Ｏ３内氧化层构成，氧化膜的粘附性较好。高Ａｌ（５ｗｔ％），低Ｃｒ（９ｗｔ％）、Ｓ（０３００５ｗｔ％）含量，且不含Ｚｒ的合金其氧化膜主要由Ａｌ２Ｏ３，ＴｉＯ２，Ｃｒ２Ｏ３构成，氧化膜的粘附性较差，但在该合金中加入０．１Ｗｔ％Ｓ和０．１Ｗｔ％Ｚｒ，氧化膜的粘附性变好，而恒温氧化速率增加。文中对实验结果进行了综合分析。