Abstract: In order to obtain high-quality rare earth containing single crystal blades， the effect of La content on the wettability and interface reaction between CMSX-4 single crystal alloy and ceramic mould was studied by the droplet method.The experimental results show that when the 90×10^-6 La is added， the wetting angle between the alloy and the mould decreases slightly， and only Al reacts with SiO₂ in the mould and the reaction product is Al₂O₃. When the La content in the alloy reaches 143×10^-6， and the wetting angle between the alloy and the mould decreases significantly， and both La and Al in the alloy react with SiO₂ in the mould. Subsequently the La content continue to increase， and the lanthanum aluminate compounds with different La and Al atomic ratios are precipitated at the interface， and the wetting angle changes little. It can be seen that in the present experitment 143×10^-6 is the critical content of interfacial reaction of La in CMSX-4 single crystal alloy， and the reaction between La and SiO₂ can improve the wettability of the alloy/mould system.

Key words: La Content, CMSX-4 Single Crystal Alloy, Wettability, Interfacial Reaction

摘要： 为了获取高质量的含稀土单晶叶片，采用座滴法研究了La含量对CMSX-4单晶合金与陶瓷型壳润湿性及界面反应的影响。实验结果表明，添加90×10^-6 La时，合金与型壳的润湿角略有下降，合金中仅发现Al与型壳中的SiO₂发生反应，形成产物为Al₂O₃；当合金中w［La］达到143×10^-6时，合金与型壳的润湿角显著下降，合金中的La和Al都与型壳中的SiO₂发生反应；随后继续增加La含量，界面处析出不同La、Al原子比的铝酸镧化合物，润湿角变化不大。由此可见，实验中，143×10^-6为CMSX-4单晶合金中La发生界面反应的临界含量，而且，La与SiO₂的反应可以提高合金/型壳体系的润湿性。

关键词: La含量, CMSX-4单晶合金, 润湿性, 界面反应