Effect of growth promoters on chemistry synthesis of Cr3C2 nanowhiskers from water-soluble precursors

Cr3C2 nanowhiskers with a diameter size of ~50 nm were synthesized at mild condition (800 °C for 2 h) by a new precursor method. The process has two steps in which the amorphous Cr2O3-C mixtures containing whisker growth promoters were first produced from water-soluble precursor solution by air drying and subsequent calcining at 400 °C for 1 h, and secondly carburized at 750-800 °C. Phase composition and morphology of as-prepared products were discussed by X-ray diffraction and scanning electron microscopy, respectively. Furthermore the transmission electron microscope was used to identify the fine structure of the as-prepared products. The results showed that the melting point and addition amount of the selected grow agent were two critical controlling factors during synthesizing Cr3C2 nanowhiskers, in which the addition of 4 wt% NaCl + KCl (molar ratio of 1:1) mixture with the melting point of ~650 °C is optimal. Fe/Co/Ni catalysts are not suitable for the synthesis of Cr3C2 nanowhiskers as whisker growth promoters by the precursor method.