Synthesis and characterization of a MoWC-WC-NiC nanocomposite via mechanical alloying and sintering

• Spherical bimetallic carbide was synthesized by mechanical alloying and sintering.
• WC-MoWC-NiC nanocomposite with a crystallite size less than 11 nm was formed.
• TEM results showed that the particle size of the spheres ranged from 2.5 to 50 nm.
• As the milling time increased, the surface area specific increased.
• Microhardness properties was obtained for the sintered powders.

MoWC-NiC-WC was produced by mechanical alloying at different grinding times as follows: 0, 40, 80, 120, 160, 200 and 240 h. A mixture of elemental powders of W, Mo, C and Ni was submitted to mechanical alloying in a ball mill under an argon atmosphere. The milled powders were sintered at 900 °C for 1 h. The phases and morphology at each stage of milling were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD indicated that by increasing the milling time from 0 to 240 h, the nanostructured carbide phases were synthesized with a crystal size ranging from 125.6 to 10.1 nm. The experimental results demonstrated that after sintered milled powder at 240 h, particles with spherical morphology were formed. The elemental maps revealed the formation of heterogeneous spheres which are primarily MoWC. The TEM results of sintered composites that were milled for 240 h showed nanoparticles ranging from 2.5 to 50 nm. As the milling time increased, the microhardness increased from 70 to 248 Hv using the sintered powder milled for 240 h. The surface area specific properties of the milled powders ranged from 21.60 to 88.15 m2g− 1.

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