Ni and NiFe alloys with different compositions have been successfully synthesized using a simple, surfactant-free polyol method. The morphological analysis demonstrated a uniform spherical nature of the alloys, with size range ∼10–30 nm. A very thin oxide layer was found to form over the alloy nanoparticles (NPs) which is weakly visible in TEM and later confirmed by XPS analysis. The magnetic properties of the Ni and NiFe NPs were measured using a vibrating sample magnetometer (VSM) at room temperature. The saturation magnetization value was found to be lowest in Ni and keeps on increasing with increasing Fe content in the composition. The resistivity, as revealed from I–V characteristics, was shown to be lowest for the permalloy (Ni₈₀Fe₂₀) phase, while the values increase with further increment in the Fe content. The microwave shielding properties of the Ni and its Fe alloy NPs were investigated in the Ku band range. The lower EM wave transmittance with good reflection and absorption coefficients is responsible for the high shielding values. All of the alloys tested in this investigation showed excellent microwave shielding properties ranging from −21 to −41 dB in the entire Ku band, for ∼1 mm thick samples. The lowest EMI shielding range (−21 to −29 dB) was noted for Ni NPs while the highest was observed in the case of permalloy (−30 to −41 dB). The rest of the NiFe combinations show intermediate shielding effectiveness as compared to Ni and permalloy. Certainly, all of the NiFe alloy combinations we tested showed excellent EMI shielding above −30 dB, with significant enhancements in the absorption shielding efficiency. These alloys are good candidates for EMI shielding having the ability to attenuate 99.9% of electromagnetic radiation.

中文翻译：

---

多元醇衍生的Ni和NiFe合金可有效屏蔽电磁干扰†

使用简单的无表面活性剂多元醇方法已成功合成了具有不同成分的Ni和NiFe合金。形态分析表明，合金具有均匀的球形性质，尺寸范围约为10–30 nm。发现在合金纳米颗粒（NPs）上形成了非常薄的氧化物层，该氧化物层在TEM中微弱可见，后来通过XPS分析得到证实。使用振动样品磁力计（VSM）在室温下测量Ni和NiFe NP的磁性。发现饱和磁化值在Ni中最低，并且随着组合物中Fe含量的增加而保持增加。的电阻率，如从显示我- V特性，被证明是最低的为坡莫合金（镍₈₀的Fe ₂₀）相，而随着Fe含量的进一步增加而增加。在Ku波段范围内研究了Ni及其铁合金NPs的微波屏蔽性能。具有良好反射和吸收系数的较低EM波透射率是造成较高屏蔽值的原因。在这项研究中测试的所有合金均显示出优异的微波屏蔽性能，在大约1 mm厚的样品中，整个Ku波段的范围从-21到-41 dB。Ni NPs的最低EMI屏蔽范围（−21至-29 dB）被发现，而坡莫合金的最高EMI屏蔽范围（−30至-41 dB）被发现。与Ni和坡莫合金相比，其余的NiFe组合物表现出中等的屏蔽效果。当然，我们测试过的所有NiFe合金组合均表现出出色的EMI屏蔽性能，高于-30 dB，大大提高了吸收屏蔽效率。这些合金是EMI屏蔽的良好候选材料，能够衰减99.9％的电磁辐射。