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。

HIGH TEMPERATURE OXIDATION OF SEVERAL Ni-Cr-Al LOW SEGREGATION SUPERXLLOYS

Three kinds of Ni-Cr-Al alloys with different amountB of Cr, Al, Co, Ti etc. and trace elements of S and Zr were oxidized isothermally and cyclicly at 1000～1100℃. For the alloy with relatively high amount of Cr(16 wt%) and low amounts of Al(3.5 wt%) and S(≤0.005 wt%), the oxide scale formed after oxidation at steady state stage consisted of a continuous and compact protective Cr2O3 outer layer and dendritic shape Al2O3 internal oxidation zone. The scale adherence demonstrated by cyclic oxidation was fairly good. For the alloy with relatively high amount of Al(5 Wt%) and low amounts of Cr(9 wt%) and S(≤0.005 wt%), the oxide scale consisted mainly of Al2O3,TiO2, Cr2O3 and spinels and the scale adherence was rather poor, but addition of S(0.1 wt%) and Zr(0.1 wt%) into this alloy improved the scale adherence. Small amount of S(≤0.005 Wt%) had no obviously adverse effects on the adherence of Cr2O3 scale. The simultaneous additions of relatively high amounts of S(0.1 Wt%) and Zr(0.1 Wt%) increased the oxidation rate of Al2O3 forming Ni-Cr-Al alloy. The addition of small of Zr(0.1 wt%) could minimize the negative effects of S on the adherence of AlO3 scale.