Effect of C and Hf Contents on the Interface Reactions and Wettability between a Ni3Al-Based Superalloy and Ceramic Mould Material

The influence of active elements C and Hf on the interface reactions and wettability between a Ni3Al-based superalloy and the ceramic mould material was studied by using a sessile drop experiment. The microstructure of the alloy interface was investigated by scanning electron microscopy analysis and the phase identification was performed by X-ray diffraction analysis. The results show that interface reactions occur as C and Hf contents reach a critical value. The critical values for C and Hf to cause interface reactions are 0.12 wt% and 1.17 wt%, respectively. The reaction products contain HfO2 and 9Al2O3·Cr2O3. Adsorptions of Hf and interface reactions improve the wettability obviously.