| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1603931 | International Journal of Refractory Metals and Hard Materials | 2011 | 7 Pages |
Nanocrystalline tungsten carbide has been obtained by reduction/carburization at low temperature from precursors obtained by freeze-drying of aqueous solutions. Nanocrystalline WC powders with a adequate content of carbon were mixed with submicrometric Cobalt powder (12 wt.%), obtained by same synthesis method, and sintered in vacuum furnace. The cemented carbides fabricated from experimental powders were compared with both commercial ultrafine and nanocrystalline WC-12Co mixtures consolidated by the same route. The synthesised powders were characterized by X-ray powder diffraction, elemental analysis and scanning and high resolution transmission electron microscopy. On the other hand, density, microstructure, hardness and fracture toughness together with X-ray diffraction analysis of the sintered materials were evaluated. The cemented carbides obtained from synthesised powders exhibited a WC platelet-based homogeneous microstructure. This anisotropic growth might be due to the presence of stacking faults parallel to the basal plane in the starting WC powder, which would promote the defect-assisted preferential growth. These materials showed excellent mechanical properties, with a superior hardness/fracture toughness combination compared to materials prepared from commercial mixtures.
Research Highlights►Nanocrystalline WC powder has been obtained by reduction/carburization at low temperature from freeze-dried precursors. ►The cemented carbides obtained from synthesised powders exhibit a WC platelet-based homogeneous microstructure. ►The WC morphology is due to the presence of staking fault of the starting powder that promotes a defect-assisted preferential growth. ►The cemented carbides obtained from synthesised powders show an excellent hardness/fracture toughness combination.
