High-temperature characterization of reactively processed nanostructure nickel aluminide intermetallics
High-temperature characterization of reactively processed nanostructure nickel aluminide intermetallics
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DOI：
10.1016/j.jallcom.2006.09.049
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发表时间：
2007-08
影响因子：
6.2
通讯作者：
S. Moussa;M. S. El-shall
中科院分区：
文献类型：
--
作者：
S. Moussa;M. S. El-shall
从单质纳米粉末开始，在800℃和1000℃两种不同温度下（在10% SO2、90% He气氛下），对反应性粉末加工纳米结构镍铝化物Ni3Al和NiAl（添加和不添加微合金化物）的高温氧化行为进行了详细的研究，并对其在800℃下100h的硫化行为进行了详细的研究。讨论了在给定曝光时间t (h)和温度下氧化垢形成的单位面积增重（mg/cm2）。用热力学和动力学方法解释了氧化机理。纳米结构晶粒的形成提高了材料的高温抗氧化/或抗硫化性能。此外，添加少量Nb（高达4wt%）作为微合金化元素，与无微合金化的金属间化合物相比，其高温抗氧化/抗硫化性能显著提高。结果表明，纳米NiAl（含微量合金元素和不含微量合金元素）比纳米Ni3Al（含微量合金元素和不含微量合金元素）具有更好的高温抗氧化/抗硫化性能。利用XRD和SEM/ eds分析，分别对纳米结构铝化物在1000℃、200h和800℃、100h高温氧化/硫化处理后的氧化相进行了表征。
A detailed study of the high-temperature oxidation behavior of reactively powder processed nanostructure nickel aluminides Ni3Al and NiAl (with and without microalloying additions) starting from elemental nanopowders in air at two different temperatures (800 and 1000°C) for 200h was carried out, as well as the sulphidation behavior (in 10% SO2, 90% He atmosphere) at 800°C for 100h. The weight gain per unit area (mg/cm2) due to oxide scale formation at a given exposure time t (h) and temperature was discussed. Thermodynamics and kinetics were used to explain the oxidation mechanism. The high temperature oxidation/or sulphidation resistance was improved due to nanostructure grains formation. Also, additions of a small amount of Nb (up to 4wt%) as microalloying element resulted in a significant increase in the high temperature oxidation/ or sulphidation resistance compared to the microalloying free intermetallics. Also, the results indicated that nanostructure NiAl (with and without micro-alloying elements) showed superior high temperature oxidation/or sulphidation resistance compared to the nanostructure Ni3Al (with and without micro-alloying elements). Both XRD and SEM/EDS-analysis were used to identify the oxide phases present after the high temperature oxidation/or sulphidation exposure of nanostructure aluminides at 1000°C after 200h, and at 800°C after 100h, respectively.