Evolution of structural and thermal properties of carbon-coated TaC nanopowder synthesized by single step reduction of Ta-ethoxide

Abstract

Carbon-coated nano tantalum carbide (TaC) has been synthesized at 800 °C using tantalum-ethoxide precursor by the single step chemical reaction route without using any external carbon source. The XRD results of the synthesized samples indicate that formation of TaC starts immediately upon heating but the complete transformation is observed only after 10 h of holding at 800 °C. The 10h sample shows distinct decarburization and oxidation peaks in DSC/DTG. The surface weighted sizes obtained from double-Voigt method were confirmed by BET. The BET analysis shows that synthesized powders have large surface area and contain a mixture of micropores and mesopores. The morphology and particle size distribution analysis shows that the powders are of faceted to spherical shape with thin carbon coating having size variation primarily between 20–40 nm. DSC/TG, XRD and microstructure analysis results have been used to predict the mechanism for the formation of the carbon coated nano-TaC particles.