Synthesis and classification of WC and W metals via organic–inorganic complex precursors

Abstract

Mono-tungsten carbide (WC) and tungsten (W) have been successfully synthesized and classified by controlling organic inorganic hybrid precursors. Tungstic acid (H 2 WO 4 ) was dissolved into ammonium water and then citric acid (C 6 H 8 O 7 ) as a carbon source was dissolved into the H 2 WO 4 solution. The precursors, which were obtained by drying the chemical complex solutions, were heated at 1473 K for 1 h with Ar gas flow by a conventional electric furnace. Classification of WC and W was achieved by controlling the precursor processing conditions. In terms of making WC only, two important processing factors were revealed. One, the C/W molar ratio of an organicinorganic hybrid precursor should be more than 4.0, and two, the obtained chemical complex should be re-dissolved and aged for more than 24 h. Tungstic ions in the re-dissolved chemical complex solution may be changed into polyanions. The sizes of the obtained WC particles and W metal were approximately 100 nm and 2¯m, respectively.