Up-scalable preparation of nano zirconium carbide powder in liquid polymeric precursor and its pyrolysis mechanism

Abstract

Nano size ZrC powder was prepared by liquid polymeric precursor method. Zirconium n-butoxide (Zr(O n Bu) 4 ) and benzoylacetone (BA) were mixed directly with different molar ratios to synthesize transparent liquid zirconium carbide single-source precursors. The carbon content in the precursor could be changed by adding different amount of BA. X-ray pure ZrC was obtained when the molar ratio of BA/Zr(O n Bu) 4 was 4.6:1. The viscosity of the precursor was very low (<8 mPa s) without the addition of solvents. Zirconium carbide powders were fabricated by the pyrolysis at 800 °C in argon and subsequent heating at various temperatures in vacuum for carbothermal reduction reaction. The pyrolysis behavior, phase composition and transformation, and microstructure of the as-fabricated ZrC powders were analyzed. The gases of CH 4 , CO and CO 2 released due to decomposition and evaporation of the organic component and transformation from ZrO 2 to ZrC during pyrolysis resulted in total 60–70% mass loss. The average grain size of the synthesized X-ray pure ZrC powders was less than 30 nm. Meanwhile, the pyrolysis mechanism of nano zirconium carbide powder was deduced.