Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

The purpose of this study is to prepare WO₃ nanopowders by high-energy milling in mixture gas (7 % H₂+Ar) with various milling times (10, 30, and 60 min). The phase transformation, particle size and light absorption properties of WO₃ nanopowders during reduction via high-energy milling are studied. It is found that the particle size of the WO₃ decreases from about 30 μm to 20 nm, and the grain size of WO₃ decreases rapidly with increasing milling time. Furthermore, the surface of the particles due to the pulverization process is observed to change to an amorphous structure. UV/Vis spectrophotometry shows that WO₃ powder with increasing milling times (10, 30, 60 min) effectively extends the light absorption properties to the visible region. WO₃ powder changes from yellow to gray and can be seen as a phenomenon in which the progress of the color changes to blue. The characterization of WO₃ is performed by high resolution X-ray diffractometry, Field emission scanning electron microscopy, Transmission electron microscopy, UV/Vis spectrophotometry and Particle size analysis.