Fabrication of Ti2AlN/TC4 interpenetrating phase composites and their corrosion resistance in marine environment

Ti₂AlN/TC4 interpenetrating phase composites (Ti₂AlN/TC4 IPCs) were successfully fabricated via hybrid SLM 3D printing and hot-pressing techniques. The electrochemical behavior of Ti₂AlN/TC4 IPCs in 3.5 wt% NaCl solution was studied. The results showed that the surface of IPCs with network structure Ti₂AlN reinforcement exhibited remarkably lower current density, higher impedance and fewer passive film defects compared to the TC4 alloy. The higher content and optimized ratio of Al₂O₃ and TiO₂ across the film depth made the excellent chemical stability of TiO₂ fully combined with the better sealing of Al₂O₃, which improved the stability and compactness of surface passive film of the network structure IPCs. Furthermore, the abundant Ti(OH)_x on the film surface contribute additional stabilization to the passive film.The continuous Ti₂AlN network physically blocked the diffusion of corrosion while the optimized passivation capability of transition layer chemically stabilized vulnerable metal/ceramic interface. This dual protection mechanism, combining physical barrier effects and electrochemical passivation, fundamentally accounted for the superior corrosion resistance of the Ti₂AlN/TC4 IPCs.