Fabrication of tungsten nanopowder by combustion-based method

In this work, tungsten nanopowder was prepared by solution combustion synthesis (SCS) and hydrogen reduction. First, needle-like W18O49 as precursor was fabricated by SCS. Subsequently, hydrogen reduction of as-synthesized precursor was utilized to prepare tungsten nanopowder. The precursor synthesized by SCS exhibits high reduction reactivity and can be completely reduced to pure tungsten nanopowder at as low as 700 °C for 2 h. The tungsten particles reduced at 700 °C are spherical or elliptical and the particle size is 20-30 nm. The sintering behavior of the as-prepared tungsten nanopowder was investigated by analyzing the sintered compacts obtained at different sintering temperatures. 93.3% of relative density of the compact could be obtained at sintering temperature of 1200 °C. The microhardness of the compact sintered at 1500 °C reached the highest point of 587.14 Hv0.2.