Al_2O_3型壳与DD6单晶合金的界面反应

Interface Reactions Between DD6 Single Crystal Superalloy and Al_2O_3 Molds

采用SEM、EDS、XRD等手段研究了DD6单晶合金与陶瓷型壳的界面反应。结果表明,DD6高温合金与Al_2O_3型壳的黑色界面反应产物主要是α-Al_2O_3,并伴有FeCr_2O_4、(Fe,Ni)固溶体等多种成分相,界面反应层的厚度一般为5～6μm;界面反应后陶瓷型壳内表面出现了TaO、NiO、HfO_2等多种反应产物;降低表面粗糙度、控制型壳矿化剂中的Fe_2O_3杂质含量,能够有效抑制界面反应的产生。

The interface reactions between DD6 single crystal superalloy and ceramic shells were investigated by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction analysis （XRD）. The results show that the black reaction products are α-Al2O3, accompanied by FeCr2O4 and taenite-（Fe, Ni） at the same time. The thickness of the interface reaction layer is about 5～6 μm. The reaction products TaO, NiO, and HfO2 appear on the prime coat of the ceramic shell. The interface reactions can be inhibited by reducing the surface roughness and controlling the content of Fe2O3 in the mineralizer.