Surface modification of low carbon steel and alloy steel by boriding diffusion coating

Abstract

In this study, Inconel 718 and mild steel rods with diameter 20 mm were undergo boriding diffusion coating by using pack cementation method at 900°C for 30, 60 and 90 minutes. This surface modification was conducted to improve surface properties in term of mechanical and morphology. Structural characterization was made by optical microscopy (OM) and X-ray diffraction (XRD) analysis. Mechanical characterization was made by Vickers microhardness. The OM micrograph shows that the greenish brown surface that indicate boride layer was formed on Inconel 718 and mild steel. Besides, XRD pattern revealed that borided samples comprised nickel silicide (Ni2Si), nickel boride (Ni4B3) and iron boride (FeB) layers for Inconel 718, while for mild steel consist of iron boride (FeB and Fe2B) layers. Upon boriding, surface hardness was significantly increased with a corresponding increase in heating time. Based on the results on this study, boriding diffusion coating can be applied in industry to upgrade the properties of material.