Plasma electrolytic surface carburizing and hardening of pure iron

Abstract

In this study, surface carburizing of pure iron was investigated in aqueous solution, which consists of water, glycerin, and NH 4Cl, for a very short period of time. The formation of hard carbon-rich layer on the surface of pure iron was confirmed by XRD analysis. SEM study combined with EDS showed the presence of carbon in the coated layer. Moreover, RF-Glow Discharge Optical Emission Spectrometry (RFGDOES) presents only carbon diffusion into the base material. Metallographic and SEM studies revealed that a uniform and compact carbon-rich layer was firmly sticking to the surface of the pure iron, and there was no crack observed between a carburized layer and a substrate. The average thicknesses of carbon-saturated layers were changing from 12 μm for 10 s to 78 μm for 60 min. The hardness of the carbon-rich layer on the substrate was 850 HV, while the hardness of the substrate was 150 HV.