Influence of the process temperature on the steel microstructure and hardening in pulsed plasma nitriding

In this paper we report the influence of temperature (260 to 510 °C) on the AISI H13 steel microstructure and hardness in pulsed plasma nitriding processes. The experimental results show that bulk nitrogen penetration is well represented by a temperature-activated law. Even at the lowest studied temperatures, grain boundary diffusion causes nitrogen to move relatively deep in the bulk sample. The microstructure was studied by X-ray diffraction analysis at grazing angle and in the Bragg–Brentano configuration. Scanning Electron Microscopy with spatially resolved X-ray energy disperse spectroscopy was also employed to map nitrogen influence on the morphology of the material. Also, surface (frontal) and profiling nano-indentation was utilized to elucidate the effect of the temperature on the nitrited material hardness.