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 unmi...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.展开更多
The effect of Si on the austenite stabilization, martensite morphology, and magnetic properties in Fe-26%Ni-x%Si （x=3.5, 5, and 6） alloys have been studied by means of transmission electron microscopy （TEM） and M...The effect of Si on the austenite stabilization, martensite morphology, and magnetic properties in Fe-26%Ni-x%Si （x=3.5, 5, and 6） alloys have been studied by means of transmission electron microscopy （TEM） and M？ssbauer spectroscopy techniques. TEM observations reveal that the martensite morphology is closely dependent on the Si content. The volume fraction changes of martensite and austenite phases, the hyperfine magnetic field, and isomer shift values have been determined by Mssbauer spectroscopy. The M？ssbauer study reveals that the hyperfine magnetic field, the isomer shift values and the volume fraction of martensite decrease with increasing Si content.展开更多
Fe96-xZrxn4 （1〈x〈12） nanowires were prepared by electrodepositing into anodic aluminum oxide templates. The diameter of nanowires used is 100 nm and the aspect ratio is 75. The structure of the nanowire arrays was...Fe96-xZrxn4 （1〈x〈12） nanowires were prepared by electrodepositing into anodic aluminum oxide templates. The diameter of nanowires used is 100 nm and the aspect ratio is 75. The structure of the nanowire arrays was studied by selected area electron diffraction, X-ray diffraction and MOssbauer spectrometer. The phase structure of Fe96_xZrxB4 nanowires is changed from a crystalline phase to a homogenous amorphous phase with the increasing of Zr content. The Fe96_xZrxB4 nanowires are com- posed of a-Fe-like and Zr-rich FeZrB phases. With the increasing of Zr composition, the atoms of Fe site in both phases are more disorderly, and the ct-Fe-like phase decreasing with the FeZrB phase increasing. The anisotropy of Fe96_xZrxB4 nanowires becomes more obvious with the increasing of Zr content, and the easy magnetizing axis is parallel to the nanowire arrays.展开更多
An X-ray diffraction and 57Fe MOssbauer effect study of mechanically alloyed Fe80Al20 is presented. X-ray measurements indicate that the disordered bcc α-Fe（A1） solid solution was formed after 2 h of milling, while...An X-ray diffraction and 57Fe MOssbauer effect study of mechanically alloyed Fe80Al20 is presented. X-ray measurements indicate that the disordered bcc α-Fe（A1） solid solution was formed after 2 h of milling, while the analysis of Mrssbauer spectra suggested that total dissolution of aluminium is achieved after 10 h of milling. These differences can be attributed to： （i） rapid nanocrystallization of aluminium and/or （ii） small particles with small amounts of aluminium cannot be detected by the X-ray diffraction technique.展开更多
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)+1 种基金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)
文摘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 Research Fund of Kirikkale University (No.2006/15)
文摘The effect of Si on the austenite stabilization, martensite morphology, and magnetic properties in Fe-26%Ni-x%Si （x=3.5, 5, and 6） alloys have been studied by means of transmission electron microscopy （TEM） and M？ssbauer spectroscopy techniques. TEM observations reveal that the martensite morphology is closely dependent on the Si content. The volume fraction changes of martensite and austenite phases, the hyperfine magnetic field, and isomer shift values have been determined by Mssbauer spectroscopy. The M？ssbauer study reveals that the hyperfine magnetic field, the isomer shift values and the volume fraction of martensite decrease with increasing Si content.
基金supported by the National Natural Science Foundation of China(Grant No.11074312)the Fundamental Research Funds for the Central Universities(Grant No.1112KYQN35)+3 种基金the"985 project"(Grant No.98507-012009)the Ministry of Education of Chinathe National Innovation and Training(Grant No.GCCX 2012110014)the Undergraduate Research Training Program of Minzu University of China(Grant Nos.URTP 2012110009 and URTP 2012110010)
文摘Fe96-xZrxn4 （1〈x〈12） nanowires were prepared by electrodepositing into anodic aluminum oxide templates. The diameter of nanowires used is 100 nm and the aspect ratio is 75. The structure of the nanowire arrays was studied by selected area electron diffraction, X-ray diffraction and MOssbauer spectrometer. The phase structure of Fe96_xZrxB4 nanowires is changed from a crystalline phase to a homogenous amorphous phase with the increasing of Zr content. The Fe96_xZrxB4 nanowires are com- posed of a-Fe-like and Zr-rich FeZrB phases. With the increasing of Zr composition, the atoms of Fe site in both phases are more disorderly, and the ct-Fe-like phase decreasing with the FeZrB phase increasing. The anisotropy of Fe96_xZrxB4 nanowires becomes more obvious with the increasing of Zr content, and the easy magnetizing axis is parallel to the nanowire arrays.
文摘An X-ray diffraction and 57Fe MOssbauer effect study of mechanically alloyed Fe80Al20 is presented. X-ray measurements indicate that the disordered bcc α-Fe（A1） solid solution was formed after 2 h of milling, while the analysis of Mrssbauer spectra suggested that total dissolution of aluminium is achieved after 10 h of milling. These differences can be attributed to： （i） rapid nanocrystallization of aluminium and/or （ii） small particles with small amounts of aluminium cannot be detected by the X-ray diffraction technique.
