Unveiling the transpassive film failure of 3D printing transition alloys

The failure of transpassive films on transition metal alloys was investigated. results show that the film 3D printing nickel-based superalloy in flowing NaNO 3 solution is dominated by self-induced cracking niobium-segregated phases and erosion-induced degradation assisted cation vacancy condensation at metal/barrier layer interface. Secondary passivation induces formation a film, nature which has been debated for decades. findings are consistent with bi-layer structure comprising point-defective barrier grows into substrate alloy precipitated outer layer. • Failure mechanism investigated first time. exist vacancies confirmed. film.