Microstructure analysis of boronized pure nickel using boronizing powders with SiC as diluent

Abstract

In this study, boronizing of 99.9% pure nickel was performed by means of a powder-pack method using Commercial LSB-II powders (that contained SiC) at 850, 900 and 950 °C for 2, 4, 6 and 8 h, respectively. The coated samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and hardness tests. The presence of boride (Ni 2B) and silicide (Ni 5Si 2, Ni 2Si) phases, formed on the surface of boronized pure nickel, were confirmed by X-ray diffraction analysis. The Ni 3Si phase was found when pure nickel was boronized at 850 °C for 2 h. Depending on boronizing time and temperature, the thickness of coating layer ranged from 36 to 237 μm. The hardness values were 832 HV 0.01 for the silicide layer, 984 HV 0.01 for boride layer, and 139 HV 0.01 for the Ni substrate.