Synthesis, sintering, and order-disorder transitions of non-stoichiometric nanocrystalline VCx

The present study provides a detailed description of all phenomena related to fabrication of dense vanadium carbide ceramics from nanopowders. The solid-state synthesis and characterization of initial microcrystalline and milled nanocrystalline VCx particles with x of 0.70-0.86 are documented. Densification kinetics of milled powders is investigated and sintered ceramics are analyzed in terms of hardness, microstructure, and phase composition. The synthesized and milled powders demonstrate order-disorder transitions during heat treatment, but the transition point is shifted for milled samples due to decarburization and partial dissolution of oxygen impurities. Overall, milled VC0.86 was found to be the most promising material because it provided single-phase ceramics with 97% density and 19 GPa hardness after sintering at 1300 degrees C for 30 min under vacuum.

Automated summary

This study provides a detailed description of the fabrication process and characteristics of dense vanadium carbide ceramics from nanopowders. It investigates the solid-state synthesis, milling process, densification kinetics, and properties of the ceramics. The results show order-disorder transitions during heat treatment, and the most promising material is milled VC0.86, which achieved high density and hardness after sintering.