退火处理对FeCo纳米粒子吸波性能的影响

Effect of annealing treatment on microwave absorbing properties of FeCo nanoparticles

用KBH4作为还原剂,采用化学还原法制备FeCo纳米粒子,然后在400~600℃下退火。利用X射线衍射仪、扫描电镜、X射线光电子能谱仪和振动样品磁强计对FeCo纳米粒子进行表征,用网络矢量分析仪测定其电磁参数,并分析FeCo的吸波性能,研究退火温度对FeCo纳米粒子吸波性能的影响。结果表明,化学还原法制备的FeCo纳米粒子,在厚度为5 mm时对频率为2.24 GHz电磁波的反射损耗最大,为-14.9 dB,损耗机制以介电损耗为主。随退火温度从400℃升高到600℃,FeCo纳米粒子的介电损耗逐渐减小而磁损耗逐渐增大,在400℃退火后的FeCo粒子具有最优的电磁匹配特性和最高的反射损耗,在厚度为3.55 mm时对4.48 GHz电磁波的反射损耗为-49.14 dB。

FeCo nanoparticles were prepared using KBH4 as a reducing agent through chemical reduction method and then annealed at 400-600 ℃. FeCo nanoparticles were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS) and vibrating sample magnetometer(VSM). The electromagnetic parameters of FeCo nanoparticles were measured by network vector analyzer(NVA). The microwave absorbing properties of FeCo nanoparticles were analyzed. The effect of annealing temperature on the microwave absorbing properties of FeCo nanoparticles was studied. The results show that the sample prepared under chemical reduction has the maximum reflection loss of-14.9 dB at 2.24 GHz and at the thickness of 5.0 mm, and the main loss mechanism is dielectric loss. With annealing temperature increasing from 400 ℃ to 600 ℃, the dielectric loss decreases and the magnetic loss increases. The sample has the optimal matching performance and the strongest reflection loss after annealed at 400 ℃. The reflection loss of-49.14 dB at 4.48 GHz can be obtained at a thickness of 3.55 mm.