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.

Abstract
1. 서 론
2. 실험방법
    2.1 WO3 나노분말의 제조
    2.2 특성분석
3. 결과 및 고찰
4. 결 론
References

• 김명재(숭실대학교 유기신소재공학과) | Myung-Jae Kim (Department of Organic Material & Fiber Engineering, Soongsil University)
• 이광석(강원대학교 신(기능)소재공학과) | Kwang-Seok Lee (Department of Advanced Materials Engineering, Kangwon National University)
• 김경남(강원대학교 신(기능)소재공학과) | Kyung-Nam Kim (Department of Advanced Materials Engineering, Kangwon National University) Corresponding author