Synthesis and Densification of Nano-Sized W Powders Prepared by Hydrogen Reduction of Ball-Milled WO3 Powders

The synthesis and consolidation of nano-sized W powders are attempted with the combination process of hydrogen reduction of ball-milled WO(3) powder and spark plasma sintering. The reduction behavior of WO(3) is analyzed by temperature-programmed reduction. The reaction peaks for reduction of WO(3) are observed in the temperature range of 590-782 degrees C. XRD and TEM analysis reveals that oxide powder is changed to metallic W with an average particle size of 100 nm by hydrogen reduction at 900 degrees C for 1 h. The densified specimen by spark plasma sintering at 1700 degrees C under an applied pressure of 50 MPa using nano-sized W powder shows increased relative density compared with that using micron-sized W powder. The results suggested that the W bulk with increased relative density fine microstructure can be fabricated by spark plasma sintering of hydrogen-reduced WO(3) powder, more effectively.