Synthesis and Characterization of New Intermetallic Compounds for the grant entitled: Laser Processing of Advanced Magnetic Materials

摘要

This six-month work is focused mainly on the properties of novel magnetic intermetallics. In the first project, we synthesized several 2:17 intermetallic compounds, namely Nd2Fe15Si2, Nd2Fe15Al2, Nd2Fe15SiAl and Nd2Fe15SiMn, as well as several 1:12 intermetallic compounds, such as NdFe10Si2, NdFe10Al2, NdFe10SiAl and NdFe10MnAl. In the second project, seven compositions of NdxFe100-x-yBy ribbons were prepared by a melt spinning method with Nd and B content increasing from 7.3 and 3.6 to 11 and 6, respectively. The alloys were annealed under optimized conditions to obtain a composite material consisting of the hard magnetic Nd2Fe14B and soft magnetic -Fe phases, typical of a spring magnet structure. In the third project, intermetallic compounds of the type Zr1Cr1Fe1T0.8 with T=Al, Co and Fe were subjected to hydrogenation. In the fourth project, we performed three crucial experiments. In the first experiment, we subjected a mixture of Fe3O4 and Fe (80-20 wt %) to mechanochemical activation by high-energy ball milling, for time periods ranging from 0.5 to 14 hours. In the second experiment, we ball-milled Fe3O4:Co2+ (x=0.1) for time intervals between 2.5 and 17.5 hours. Finally, we exposed a mixture of Fe3O4 and Co (80-20 wt %) to mechanochemical activation for time periods ranging from 0.5 to 10 hours. In all cases, the structural and magnetic properties of the systems involved were elucidated by X-ray diffraction (XRD), Mossbauer spectroscopy and hysteresis loop measurements. The four projects resulted in four papers, which are currently being considered for publication in Intermetallics, IEEE Transactions on Magnetics, Journal of Materials Science Letters and Journal of Materials Science. The contributions reveal for the first time in literature the effect of substitutions on the hyperfine magnetic field of neodymium-based intermetallics, the correlation between structure and magnetic properties in spring magnets, the unique effects induced by hydrogenation on the hyperfine parameters of iron-rich intermetallics and the characteristics of the ball milling process in systems containing magnetite.