Evolution study of microstructure and electromagnetic behaviors of Fe–Co–Ni alloy with mechanical alloying

Comprehensive utilization of experimental measurement and quantum-mechanical calculation were implemented to study the properties of Fe–Co–Ni alloy prepared by mechanical alloying using planetary ball mill. The related properties were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), vector network analyzer. Moreover, the theoretical calculation was conducted based on density functional theory (DFT) within the generalized gradient approximation (GGA). The systematical discussions about microstructures, including morphology, phase structure, grain size, internal strain, were carried out. The electromagnetic properties were also talked combining with the microstructure analysis, including saturation magnetization (MS), coercivity (HC), electromagnetic parameter (permeability μ and permitivity ɛ) and microwave reflection loss (RL). Results showed that the above properties changed with the alloying process: α-Fe (Co) powders milling for 25 h had the maximum MS (153 emu/g). The microwave absorbing ability was enhanced with increased milling time, and the minimum RL (−32.4 dB) was obtained at about 9 GHz after milling for 90 h.