Preparation of the NiFe2O4 electrochemical film for the solid-state reference electrode based on EB-PVD

As the key material of the solid-state reference electrode, NiFe2O4 electrochemical film, was prepared by the electron beam-physical vapor deposition technique for the corrosion monitoring sensors of the reinforced concrete structures. The Ni–Fe binary alloy film was obtained by two-source evaporation based on the evaporation currents control. After the heat treatment and the post-oxidation processes, NiFe2O4 spinel film was achieved successfully. Furthermore, the microstructure, phase composition, component and texture of the prepared state, heat treatment state and oxidized state films were investigated in detail, respectively. The results indicate that the NiFe2O4 electrochemical film was very suitable for mass production by using the optimized preparation processes.