A Novel Approach to the Rapid in situ Synthesis of Tungsten Carbide Nanopowder by Plasma Milling and Carbothermal Reduction

Abstract

This work prepares nanocrystalline tungsten carbide (WC) powder using conventional ball milling or plasma milling (P‐milling) to process tungsten trioxide (WO3)–carbon (C) mixtures, with subsequent carbothermal reduction. The aim is to assess the effects of a discharge plasma on the microstructure of these materials. The results indicates that WC powders with particle sizes of less than 100 nm could be fabricated through heating at a relatively low temperature of 1150 °C for 1 h under vacuum after P‐milling. This process is found to allow a lower processing temperature and provided more complete carburization in comparison with conventional ball milling. P‐milling is determined to produce more loosely adhering WO3 nanoparticles and a higher surface area, resulting in more reactive sites and a larger contact area between WO3 nanoparticles and C atoms. This technique simultaneously generates more oxygen vacancies and defects on the surfaces of the WO3 and C, respectively, based on the use of a plasma discharge. It is evident that this new technology permits nanocrystalline WC to be readily obtained from WO3 and C in a reduced time span and at a lower cost and greater efficiency. This technique could also be used to fabricate WC nanopowders on an industrial scale.

Fabrication of TiN-doped Ti nanocomposites with high strength and ductility by plasma-assisted ball milling and selective laser melting

“…The Ti-TiN nanocomposites were synthesized from raw atomized spherical CP-Ti powder with a diameter of about 15-53 µm (Changsha TIJO Metal Materials Co., Ltd., China) using a plasma milling device (PBMS, South China University of Technology, China). The working principle of this device has been reported previously [22][23][24][25]. In this work, mechanical ball milling was conducted during exposure to a homogeneous non-thermal N 2 gas plasma, which was generated with a pulse peak voltage of 25 kV and discharge frequency of 11.5 kHz using a single dielectric barrier discharge reactor.…”