WC-VC/Cr3C2 composite powders prepared by a carbothermic reduction-carburization process.

Ultrafine WC-VC/Cr 3 C 2 composite powders with uniform distribution of V/Cr were synthetized by a novel method composed of carbothermic reduction of the mixture of WO 3 and V 2 O 5 /Cr 2 O 3 at 1050 °C and the following carburization process at 1300 °C under hydrogen atmosphere. The effects of addition amount of VC or Cr 3 C 2 on the phase constitution, particle size and micromorphology of WC-VC/Cr 3 C 2 composite powders were investigated. The results revealed that W, C, V/Cr elements were evenly distributed in the WC-VC/Cr 3 C 2 composite powders. Moreover, the particle size of WC-0.5wt.%VC composite powder was obviously smaller than that of pure WC powder, but decreased slightly with the further increase of VC content. Furthermore, it was found that the inhibition result of Cr 3 C 2 on WC grain growth was significantly worse than that of VC. In terms of micromorphology, pure WC and WC-VC powder had the round shaped WC particles originated from the isotropic growth, while there were triangular prism shaped WC particles because of the faceting of WC particles caused by the minimization of surface energy in WC-Cr 3 C 2 composite powders. Moreover, there were also a few WC particles with the layer-by-layer microstructure owing to the anisotropic growth under the action of Cr 3 C 2. • Ultrafine WC-VC/Cr 3 C 2 powders were prepared by reduction‑carbonization process. • Particle size of WC-VC was obviously smaller than that of pure WC powder. • WC and WC-VC powders had round shaped WC particles resulted from the isotropic growth. • WC-Cr 3 C 2 powder show triangular prism shaped WC particles because of the faceting of WC. [ABSTRACT FROM AUTHOR]