A study on microstructural evolution and corrosion behavior of spark plasma sintered Fe–Cr alloy system

Iron (Fe) and chromium (Cr) powders at various concentrations of Cr (6, 9, 12 and 14 wt%) were mechanically alloyed via high-energy ball milling for 10 h. The milled Fe–Cr alloy powders were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) for understanding the impact of varying chromium content on the characteristics of the milled powder. The powder samples were then consolidated via spark plasma sintering (SPS) at 1000 °C for 45 min at 80 MPa pressure. The density of the consolidated samples was measured and found to reach a maximum of 98%. Microstructural characterization of the spark plasma sintered samples was performed using SEM and XRD. Electrochemical corrosion tests were performed on spark plasma sintered samples in 0.5 M H2SO4, 0.05 M NaH2PO4 and 1 M NaOH solutions using potentiodynamic polarization, electrochemical impedance spectroscopy and Mott–Schottky analysis. The corrosion behavior of the spark plasma sintered materials was compared with that of a wrought HT-9 steel (12Cr based ferritic–martensitic steel). The work presented here is a comparative study of microstructural evolution and corrosion behavior between the different spark plasma sintered Fe–Cr model alloys and wrought HT-9 steel.