摘要
Ball milling for long time (such as 10, 20, and 30 h) can transform Fe84.94Si9,68A15.38 alloy powders with irregular shapes into flakes. X-ray diffraction (XRD) and M6ssbauer measurements have proven that the unmilled particles and the flakes obtained by milling for 10 h have the same D03-type superlattice structure. The flakes obtained by milling for 20 h and 30 h have the same disorder a-Fe(Si, A1) structure. There are more than 6 absorption peaks in the transmis- sion MSssbauer spectra (TMSs) for the particles with D03-type superlattice structure, which can be fitted with 5 sextets representing 5 different Fe-site environments. However, only 6 TMS absorption peaks have been found for particles with a disorder a-Fe(Si, A1) structure, which can be fitted with the distributions of M6ssbauer parameters (Bhf, isomer shift). The TMS results show that the flaky particles have a stronger tendency to possess the planar magnetic anisotropy. As the result, the flakes have larger microwave permeability values than particles with irregular shapes. The conversion electron M6ssbauer spectra (CEMSs) also show the significantly different Fe-sites environments between the alloy surface and the inside.
Ball milling for long time (such as 10, 20, and 30 h) can transform Fe84.94Si9,68A15.38 alloy powders with irregular shapes into flakes. X-ray diffraction (XRD) and M6ssbauer measurements have proven that the unmilled particles and the flakes obtained by milling for 10 h have the same D03-type superlattice structure. The flakes obtained by milling for 20 h and 30 h have the same disorder a-Fe(Si, A1) structure. There are more than 6 absorption peaks in the transmis- sion MSssbauer spectra (TMSs) for the particles with D03-type superlattice structure, which can be fitted with 5 sextets representing 5 different Fe-site environments. However, only 6 TMS absorption peaks have been found for particles with a disorder a-Fe(Si, A1) structure, which can be fitted with the distributions of M6ssbauer parameters (Bhf, isomer shift). The TMS results show that the flaky particles have a stronger tendency to possess the planar magnetic anisotropy. As the result, the flakes have larger microwave permeability values than particles with irregular shapes. The conversion electron M6ssbauer spectra (CEMSs) also show the significantly different Fe-sites environments between the alloy surface and the inside.
基金
supported by the National Key Basic Research Program of China(Grant No.2010CB334702)
the China National Funds for Distinguished Young Scientists(Grant No.51025208)
the International Collaboration Project of Sichuan Province,China(Grant Nos.2011HH0001 and 2012JQ0053)
the Program for New Century Excellent Talents in Universities,China(Grant No.NCET-11-0060)