The preparation and thermal stability study of nanocrystalline tungsten carbide powder

Nanocrystalline tungsten carbide (nano-WC) powder with an average grain size of 15 nm was prepared by carbonating nanocrystalline α-W powder at 800°C in a fixed vapor reactive bed. The grain size of the nano-WC powder annealed at various temperatures was measured by X-ray diffraction. The results indicated a grain size increase of from 15 nm to 47 nm when the annealing temperature rose to 1500°C. The DSC curves of nano-WC powder were measured at heating rates of 5 K/min, 10 K/min, 15 K/min and 20 K/min, respectively. According to the Kissinger equation, the activation energy for grain growth of nano-WC was calculated to be 3.494 eV or 337 kJ/mol.