为探究超声振动对热变形钕铁硼磁体晶粒尺寸和择优取向的影响及其机制,在其热变形过程中施加超声振动,通过SEM图像和Image Pro Plus软件对磁体的晶粒尺寸分布进行分析;通过XRD图谱和SEM晶粒形貌对磁体的晶粒取向度进行分析;并对磁体的...为探究超声振动对热变形钕铁硼磁体晶粒尺寸和择优取向的影响及其机制,在其热变形过程中施加超声振动,通过SEM图像和Image Pro Plus软件对磁体的晶粒尺寸分布进行分析;通过XRD图谱和SEM晶粒形貌对磁体的晶粒取向度进行分析;并对磁体的应变激活能和磁性能进行分析。结果表明,超声振动对热变形钕铁硼晶粒存在细化作用,细晶区的平均晶粒尺寸相较于常规热变形磁体减小约50%,且提高超声功率密度可使晶粒细化作用明显增强。超声振动促进了主磁相晶粒的转动,更多晶粒c轴转至压力方向,使整体择优取向得到改善。此外,超声振动促进了磁体径向方向晶粒取向的均匀分布,减小了热变形磁体剩磁沿径向方向的差异。展开更多
Fe3O4 magnetic particles were synthesize by chemical co precipitation. Sodium oleate and poly(ethyleneglycol) 4000 were used as bilayer surfactants toenvelope the ultra fine Fe3O4 particles. Then stabilized water base...Fe3O4 magnetic particles were synthesize by chemical co precipitation. Sodium oleate and poly(ethyleneglycol) 4000 were used as bilayer surfactants toenvelope the ultra fine Fe3O4 particles. Then stabilized water base magnetic fluid was obtained. Experiments indicated that surfactants and pH value of the solution had great effect on the stability and size of the magnetic fluid when Fe3O4 particles were synthesized and enveloped. It was the first time to employ this method to prepare magnetic fluid. Using laser diffraction particle size analyzer we found that the average diameter of magnetic fluid was lessen than 84 nanometer. Its magnetization was measured on magnetic balance and the result amounted to 3.84×103A·m-1. Further more, XRD and IR analysis measurements were employed to substantiate the existence of Fe3O4 and surfactant structure. The magnetic fluid can be used as targeted part of nanometer targeted drug delivery system.展开更多
文摘为探究超声振动对热变形钕铁硼磁体晶粒尺寸和择优取向的影响及其机制,在其热变形过程中施加超声振动,通过SEM图像和Image Pro Plus软件对磁体的晶粒尺寸分布进行分析;通过XRD图谱和SEM晶粒形貌对磁体的晶粒取向度进行分析;并对磁体的应变激活能和磁性能进行分析。结果表明,超声振动对热变形钕铁硼晶粒存在细化作用,细晶区的平均晶粒尺寸相较于常规热变形磁体减小约50%,且提高超声功率密度可使晶粒细化作用明显增强。超声振动促进了主磁相晶粒的转动,更多晶粒c轴转至压力方向,使整体择优取向得到改善。此外,超声振动促进了磁体径向方向晶粒取向的均匀分布,减小了热变形磁体剩磁沿径向方向的差异。
文摘Fe3O4 magnetic particles were synthesize by chemical co precipitation. Sodium oleate and poly(ethyleneglycol) 4000 were used as bilayer surfactants toenvelope the ultra fine Fe3O4 particles. Then stabilized water base magnetic fluid was obtained. Experiments indicated that surfactants and pH value of the solution had great effect on the stability and size of the magnetic fluid when Fe3O4 particles were synthesized and enveloped. It was the first time to employ this method to prepare magnetic fluid. Using laser diffraction particle size analyzer we found that the average diameter of magnetic fluid was lessen than 84 nanometer. Its magnetization was measured on magnetic balance and the result amounted to 3.84×103A·m-1. Further more, XRD and IR analysis measurements were employed to substantiate the existence of Fe3O4 and surfactant structure. The magnetic fluid can be used as targeted part of nanometer targeted drug delivery system.
