Eddy-current-resistant SmCo₅/CaF₂ magnets produced via high-energy milling in polar and non-polar liquids

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• 作者：A.M. Gabay^a ; ^{gabay@udel.edu} ; ^{gabay@physics.udel.edu} ; M. Marinescu-Jasinski^b ; C.N. Chinnasamy^b ; J.F. Liu^b ; G.C. Hadjipanayis^a
• 关键词：Permanent magnet ; Eddy current loss ; High-energy ball milling ; Milling process control agent
• 刊名：Journal of Magnetism and Magnetic Materials
• 出版年：2012
• 期刊代码：31_03048853
• 类别：ph
• 出版时间：September, 2012
• 卷：324
• 期：18
• 页码：2879-2884
• 文件大小：1267 K

摘要

Processes of high-energy ball milling of SmCo₅ alloys were compared for three single-liquid environments without using additional surfactants. Both coarsely grained as-cast and nanocrystalline pre-milled SmCo₅ precursors showed tendency toward formation of thin flakes if milled in polar liquids (acetone and ethanol) in a marked contrast to milling in non-polar heptane. CaF₂ dielectric powder added prior to milling in the polar liquids tends to become attached on the flake surfaces. Milling in heptane in the presence of CaF₂ produces flake-like SmCo₅ particles which with increasing the milling time are found to incorporate an increasing amount of CaF₂. The SmCo₅鈥? wt%CaF₂ mixtures milled for the optimum time in both the polar and non-polar liquids were successfully hot-pressed into laminated composite magnets having intrinsic coercivity of 25-30 kOe, maximum energy product of approximately 6.5 MG Oe and electrical resistivity of 500-600 渭惟 cm, which is more than 7 times the resistivity of conventional Sm-Co magnets.