The Effect Of Y Addition On The Properties Of Fe-Ni Amorphous Alloys

Fe,Ni-based metallic glassed alloys as good magnetic materials, which have important application in power transportation, computer storage and read-write magnetic apparatus, have great economic benefit and wide application prospect. In these years, they have become one of the most important research subjects.Fe-Ni-B-Si-Nb amorphous alloy system has been extensively studied because of its excellent soft magnetic properties and glass forming ability (GFA). In this thesis, with low Y content addition in Fe-Ni-B-Si-Nb alloys, glass forming ability has been improved, and then soft magnetic properties and Oxidation resistance were investigated.With the increasing Y content, thermal stability and glass forming ability of amorphous alloys of composition (Fe43Ni29B19Si5Nb4)100-xYx (x=3,4) were obtained. It was found that the amorphous alloys with x=3 or 4 exhibit the best GFA and thermal stability, the supercooling liquid region changes from 55oC to 58 and 65oC, and Tg and Tx change from 460 oC and 515 oC to 510,568oC and 508,573oC respectively.All the results show that the thermal stability and glass forming ability of Fe-Ni-B-Si-Nb alloy systems were enhanced with Y addition.The saturation magnetization of (Fe43Ni29B19Si5Nb4)100-xYx (x=3,4) amorphous alloys were 78和90emu/g, and their coercive force were 13 Oe,and 15 Oe. After heat treatment last at 450oC, the coercive force changed to 4 and 4.5Oe.With excelent properties, (Fe43Ni29B19Si5Nb4)97Y3 amorphous sample was used to test the Antioxidant capacity. Fe43Ni29B19Si5Nb4 and (Fe43Ni29B19Si5Nb4)97Y3 samples were prepared using low purity content under low pressure. DSC measurement show that the addition of Y could decrease the Oxidation, and enhance the glass forming ability. There are almost no change on the supercooling liquid region, glass trasition temperature and crystalline temperature with Y additions. However, the supercooling liquide region changed from 55oC to 40oC in Fe43Ni29B19Si5Nb4 sample, and the saturation magnetization changed from 95emu/g to 84emu/g, but this change is not showed in the samples containing Y content.The addition of Y can enhance the ability of impurity, the reason is that with the addition of Y, the supercooling liquid region is increased, which results in the decreasing of crystalline. Also the addition Y can react with the oxygen or the harmful other impurities and form the small particles. These particles do not trigger the formation of large crystalline phases around them, thus resulting in consuming the oxygen or the other harmful impurities in the alloy.