The effect of silicon and boron doping on the microstructure of arc melted boron carbide

Abstract

In this study, B₄C, boron-doped boron carbide, and Si/B co-doped boron carbide (1.5 at.% and 2.5 at.% made with Si and SiB₆) were arc melted. Melted ingots were characterized by X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, and Vickers hardness. According to the results, doping of boron carbide with both silicon and boron was successfully achieved by arc melting. When Si/B doped boron carbide samples were examined, the same boron carbide, silicon boron, and silicon phases were found regardless of the silicon source. It was observed that dissolving silicon in boron carbide was more difficult than dissolving boron in boron carbide, and therefore, diffusion of silicon is believed to be rather short distance. It was determined that Si/B co-doped samples had higher hardness values ​​than undoped B₄C and boron doped B_6.5C. Moreover, since very high temperatures are reached in the arc melting method, it has been determined that the oxides present in the starting powders evaporate during the melting process and therefore the oxygen content of the final melt ingots is very low.