Ni-Al系金属间化合物价电子结构计算及界面反应预测

Valence Electron Structure Calculation and Interface Reaction Prediction of Phases in Ni-Al System

摘要:

应用固体与分子经验电子理论，计算了Ni-Al系各相的价电子结构和理论结合能，并应用理论结合能值进一步计算了各相的反应生成焓，通过各相生成焓的比较对界面反应生成相进行了预测。Ni、Al、Ni3Al、Ni5Al3、NiAl、Ni2Al3和NiAl3的结合能计算值分别为427.44，324.58，441.11，440.10，435.51，432.66，395.05 kJ/mol，与实验值吻合良好。在Ni/Al界面，Ni2Al3相的生成焓最小，保温过程中，Ni2Al3相将最先析出。随后，NiAl相将在Ni2Al3/Ni的界面形成，而Ni3Al相将在NiAl/Ni的界面形成。在NiAl/Ni3Al界面，Ni5Al3生成焓绝对值较小，需要在较高温度下保温较长时间才可能形成。界面反应生成相预测结果与实验结果吻合。

Abstract:

The valence electron structures, theoretical binding energies and forming enthalpy of phases in Ni-Al system were calculated based on the empirical electron theory of solids and molecules, and the interfacial reaction was predicted through comparison of the forming enthalpy of phases. The calculated binding energy values of Ni, Al, Ni3Al, Ni5Al3, NiAl, Ni2Al3 and NiAl3 are 427.44, 324.58, 441.11, 440.10, 435.51, 432.66 and 395.05 kJ/mol, which are in good agreement with experimental values. At the Ni/Al interface, Ni2Al3 phase has a minimum enthalpy of formation, so it will be the first to precipitate in heat process; then, the NiAl phase may be formed at the Ni2Al3/Ni interface, while the Ni3Al phase may be formed at the NiAl/Ni interface. At the NiAl/Ni3Al interface, the absolute value of forming enthalpy of Ni5Al3 is small, so its formation needs high temperature and long time. The predicted results agree well with the experimental.