LAUSR

In this study, plasma nitriding process was carried out on a H13 tool steel for a duration of 12 h at 510 °C in an atmosphere of 75% nitrogen and 25% hydrogen gas. X-ray diffraction (XRD), scanning electron microscopy (SEM), and microhardness techniques were employed to study the microstructure and properties of the nitrided steel. The results of XRD analysis showed that Fe4N, Fe2N and Fe3N phases were formed at the surface of the nitride steel. Moreover, potentiodynamic polarization and electrochemical impedance spectroscopy tests in 3.5 wt% sodium chloride solution were executed to understand corrosion behavior of the nitride steel. The results of potentiodynamic polarization curves revealed that by removing the white layer from the surface of the nitrided sample, the corrosion resistance improved significantly.