坡莫合金纳米粉的恒导磁性及其磁导率的压力、频率特性

 用蒸发冷凝法制备了Fe-50wt%Ni和Fe-84wt%Ni坡莫合金的纳米微粉。经透射电镜X光能谱微区成分分析证实：微粉的成分与原材料的一致；微粉的平均粒径分别为16 nm（Fe-50Ni）和19 nm（Fe-84Ni）。在室温和36个不同的流体静压力（0.000 1~2.205 GPa）下原位测量了它们的磁化和起始磁化曲线。结果表明：（1）Fe-50wt%Ni和Fe-84wt%Ni合金纳米微粉均具有恒导滋特性；（2）这两种纳米粉的起始磁导率随静水压的变化分别为μ_i=8.16+18.2p-24.7p²+18.1p³-6.55p⁴+0.908p⁵（Fe-50Ni合金）和μ_i=5.38-0.169p+0.232p²-0.0786p³（Fe-84Ni合金）；（3）纳米粉的起始磁导率μ_i在频率高于10 MHz才降低，而Fe-50Ni合金片的μ_i在频率高于1 MHz，Fe-84Ni高于100 kHz时就开始下降，故纳米压粉磁芯可应用的频率范围可以比相应组分合金片的大1~2个数量级。

CONSTANT MAGNETIC PERMEABILITY AND ITS BOTH PRESSURE AND FREQUENCY CHARACTERISTIC IN NANOMETER-SCALE ULTRAMICRON OF PORMALLOY

By means of vacuum evaporation and condensation technique, nanometer-scale ultramicrons of Pormalloy (Fe-50wt%Ni, Fe-84wt%Ni) were prepared. It is found out with the method of TEM and X-ray diffraction that the composition of the ultramicron coincides with that of its mother alloy, and the average grain size is 16 nm (Fe-50Ni) and 19 nm (Fe-84Ni). Under room temperature and hydrostatic pressure of 36 various magnitudes ranging from 0.000 1 to 2.205 GPa the magnetization curve and initial magnetization curve were measured to reveal their relation with pressure. It is concluded: (1) The nanometer-scale ultramicron of both Pormalloy Fe-50wt%Ni and Fe-84wt%Ni possesses constant magnetic permeability; (2) Initial differential magnetic permeability, μ_i varies with the pressure as follows: μ_i=8.16+18.2p-24.7p²+18.1p³-6.55p⁴+0.908p⁵ (for Fe-50wt%Ni), μ_i=5.38-0.169p+0.232p²-0.0786p³ (for Fe-84wt%Ni); (3) μ_i of these ultramicrons decreases when f≥10 MHz, but μ_i of alloy Fe-50Ni goes down when f≥1 MHz, μ_i of alloy Fe-84Ni drops when f≥100 kHz, so applied frequency range of magnetic ultramicron core is one-two order of magnitude more than that of Pormalloy with the same composition.