Synthesis of cobalt boride nanoparticles using RF thermal plasma

•We report the first thermal plasma synthesis of cobalt boride nanoparticles.•Cobalt borides of Co2B and CoB were synthesized in boron rich conditions.•The diameter of spherical cobalt boride nanoparticles is to be 18–22 nm.•Yield and crystalline diameter of product are increased in high powder feeding.

Nanosize cobalt boride particles were synthesized from the vapor phase using a 30 kW–4 MHz radio frequency (RF) thermal plasma. Cobalt and boron powder mixtures used as precursors in different composition and feed rate were evaporated immediately in the high temperature plasma and cobalt boride nanoparticles were produced through the quenching process. The X-ray diffractometry (XRD) patterns of cobalt boride nanoparticles prepared from the feed powder ratio of 1:2 and 1:3 for Co:B showed peaks that are associated with the Co2B and CoB crystal phases of cobalt boride. The XRD analysis revealed that increasing the powder feed rate results in a higher mass fraction and a larger crystalline diameter of cobalt boride nanoparticles. The images obtained by field emission scanning electron microscopy (FE-SEM) revealed that cobalt boride nanoparticles have a spherical morphology. The crystallite size of the particles estimated with XRD was found to be 18–22 nm.

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