Effects of Heat Treatment on Microstructures and Properties of Cold Rolled Ti-0.3Ni Sheets as Bipolar Plates for PEMFC

As promising materials for bipolar plates substrate, as-cold rolled Ti-0.3Ni (wt.%) sheets were heat treated with three different processes in this work. As-cold consist of α matrix and dispersed Ti2Ni intermetallic precipitates, typical Widmanstatten microstructure can be observed after treatment. Lamellar precipitates inside the colonies. Elongation equals less than 7% while value rises up to around 20%, tensile strength decreases by more 47% Open circuit potentials at 950 °C 1 h followed wind cooling (950 °C/1 h/WC), aged 500 3 air h/WC + °C/3 h/AC), furnace h/FC) −0.536 V, −0.476 −0.486 −0.518 respectively. A potentiodynamic polarization test reveals that all specimens exhibit active–passive transition behavior. Sheets possess lowest corrosion current density (155.4 μA·cm−2). Results electrochemical impedance spectroscopy (EIS) show largest resistance (Rpol), 122.6 Ω·cm2. Moreover, steady-state densities (Iss) increase order h/WC, h/AC, h/FC according results potentiostatic polarization. This attributed various amounts precipitation caused rates.