- Guo, Pengfei;
- Lin, Xin;
- Macdonald, Digby D;
- Ter-Ovanessian, Benoît;
- Liu, Jianrui;
- Song, Guangling;
- Zhang, Yufeng;
- Ren, Yongming;
- Lan, Hongbo;
- Huang, Weidong
The failure of transpassive films on transition metal alloys was investigated. The results show that the failure of the transpassive film on 3D printing nickel-based superalloy in flowing NaNO3 solution is dominated by self-induced cracking of the film on niobium-segregated phases and the erosion-induced degradation on the film assisted by cation vacancy condensation at the metal/barrier layer interface. Secondary passivation induces the formation of a transpassive film, the nature of which has been debated for decades. The findings are consistent with a bi-layer structure comprising a point-defective barrier layer that grows into the substrate alloy and a precipitated outer layer.