Influence of reaction temperature and time on nanoboron carbide morphology and its thermal stability, optical and electronic properties

Abstract

Boron carbide powder was prepared via the carbothermic reduction reaction (CRR) using lactose (C12H22O11) and boric acid (H3BO3) as carbon and boron sources. Starting materials were mixed with an excess amount of H3BO3 stoichiometric ratio to reduce the presence of free carbon content in the produced boron carbide samples caused by the great loss of boron during the reaction. The mixed solutions of starting materials were heated in a stainless steel pot at 280 °C for 24 h. The resulted powder was carbothermally reacted under the flowing of an argon gas at different reaction temperatures and times ranging from 1300 to 1500 °C for 3 h and at 1500 °C for 1–3 h, respectively. The synthesized samples at each procedure conditions were characterized using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) techniques. The results showed that the produced samples were in the nanocrystalline scale with no carbon traces. The structural morphology of the synthesized powder studied using scanning electron microscope (SEM) and transmission electron microscope (TEM). The results indicated the possibility of producing B4C with minimal carbon residue via controlling both reaction temperature and time. A significant morphology change of the produced samples was well detected by changing the reaction time. Thermochemical properties of the as-synthesized samples at 1500 °C for 1 and 3 h also studied in order to be exploited in the proper applications. In addition, the optical properties of boron carbide was investigated by UV/visible and photoluminescence measurements along with its electronic properties.