Investigation of the effect of Argon flow on the morphology of B4C nanoparticles synthesized by the VLS method

Abstract

In this paper, new various morphologies of boron carbide were successfully synthesized using carbon black, activated carbon and boron oxide precursors as well as using cobalt nanoparticles as catalysts. Almost the whole morphology of synthesized boron carbide are consisted of smooth nanowires and nanobelts. With decreasing the carbon black particles size from 29 nm to 13 nm (29, 23, 17 and 13), the synthesis efficiency of nanowires and nanobelts are increased. With increasing the temperature from 1500 °C to 1700 °C, the amounts of nanowires and nanobelts are decreased and the amounts of nano particles and synthesizing the nanoworms are increased. By placing the catalyst nanoparticles on the crucible lid and being subjected to the argon gas flow, new morphologies of boron carbide are appeared (flower-shaped and needle-shaped are synthesized by using carbon black and activated carbon, respectively). The argon gas flow creates new branches on the main wires. The specimens were characterized by the X-ray diffraction and a scanning electron microscopy.