In situ synthesis of WC–Co nanocomposite powder via core–shell structure formation

Cemented carbide WC–Co nanocomposite powders were synthesized through in situ reduction and carbonization of a core/shell precursor in vacuum. Samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The results revealed that WC–Co composite powders can be obtained at 950 °C for 1 h and the particle size is in the range from 30 to 50 nm with good dispersion. The formation mechanism of the WC–Co composite by in situ reduction and carbonization reactions was proposed. The preparation process could be divided into three steps: first, the reagents were dissolved and mixed to an aqueous solution; second step is to synthesize a carbon encapsulated core/shell nanostructure precursor using hydrothermal route, and finally, in situ reduction and carbonization of the precursor to the desired nanocomposite powders in vacuum.

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► The hydrothermal method was firstly used to synthesize core–shell structured precursor to prepare WC–Co powder.
► WC–Co nanocomposite powder was obtained through in situ reduction and carbonization of the precursor in vacuum at 950 °C for 1 h.
► Particles of WC–Co composite indicated to have a crystallite size of 30–50 nm.