Effect of crystallographic orientation on the corrosion resistance of Ni-based single crystal superalloys

The corrosion behaviour and passive films formed on Ni-based single crystal superalloys with different orientations were investigated through the electrochemical testing and microstructural analysis. The results show that the corrosion rates of the different planes increases in the order of (001)<(111)<(011), which can be attributed to the higher equivalent atomic packing density and more compact products on the (001) plane. A parameter R-cp related to product composition is introduced to quantitatively describe the corrosion resistance of the samples. Finally, the mechanism is proposed to explain the orientation-dependent corrosion behaviour.