Microwave property of micron and sub-micron Fe₉₀Al₁₀ flakes fabricated via ball milling and jet milling routes

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• 作者：Yang Yang ; Jun Ding ; ^{msedingj@nus.edu.sg}
• 关键词：Fe/Al flakes ; Ball milling and Jet mill ; Microwave ; Reflection loss
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：5 July, 2012
• 卷：528
• 期：Complete
• 页码：58-62
• 文件大小：1273 K

摘要

Fe₉₀Al₁₀ flakes with micron- and submicron-sizes were fabricated via different milling routes. Traditional wet ball-milling process with pure ethanol as additive was performed to prepare micro-sized Fe/Al flakes. With increasing wet-milling time, the flake size increases. For Fe/Al submicron-flakes, Micron-Master Jet Pulverizer (so called jet mill) was employed. The results reveal that Fe₉₀Al₁₀ submicron-flakes with an average lateral size of 500 nm could be obtained through the combination of ball milling and jet milling. Microwave performance of the obtained Fe₉₀Al₁₀ flakes with different sizes was further studied. The complex permittivity and permeability were measured by dispersing as-prepared flakes into epoxy resin with a powder-to-epoxy volume ratio of 1:10. The results showed that flaky particles possess obvious advantage over the quasi-spherical ones on the microwave property. The theoretical calculation on reflection loss (RL) was also investigated in the range of 0.1-18 GHz. The results show that the composite including 50 渭m flaky particles shows the strongest reflection loss peak. The optimal thickness was 3.1 mm and the RL value reached 鈭?4 dB at the frequency of 7.6 GHz. Compared with as-prepared micron-flakes, the resonance frequency of the submicron flakes shifted toward higher frequency band, which is probably due to the reduction of skin effect because of the smaller size. In our study of thickness effect, the resonance peak shifted to higher frequency range with decrease in thickness for the composite containing 500 nm flakes. And the optimal thickness of the submicron flakes was 1.9 mm with the resonance peak at 14.2 GHz with a reflection loss value exceeding 鈭?0 dB in the frequency range between 12.2 and 16.8 GHz. The results reveal that the submicron flakes have the potential for making lightweight broad-band microwave absorbers applied in high frequency range.