Magnetic Characteristics of Nanocrystalline Co78Zr17B2Si1W2 Alloy Formed by Melt Spinning and Subsequent Annealing

Investigation the structural and magnetic properties of nanocrystalline Co78Zr17B2Si1W2 alloy during melt spinning and annealing processes were the main goal of this study. In this regard, samples were prepared using vacuum induction melting, melt spinning and subsequent annealing. The specimens were evaluated using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM). Based on results, nanocrystalline Co5Zr single phase with hard magnetic properties (Ms=29.5 emu/g and Hc=2.7 kOe) successfully formed during melt spinning process (at wheel speed of 40 m.s-1). The coercivity value of rapid solidified sample increased to about 3.2 kOe during annealing process up to 400°C. However, more increasing in annealing temperature lead to the transformation of non-equilibrium magnetic Co5Zr phase to stable Zr2Co11 phase, which has distractive effects on final magnetic properties

Synthesis, microstructure, magnetic and electromagnetic behavior of graphene oxide/hexagonal barium ferrite aerogel nanocomposites within the frequency range of 1–18 GHz

The fabrication of lightweight graphene oxide aerogel (GOA) composites with barium ferrite (BF) nanoparticles is investigated in this study as a method of shielding electronic and telecommunication equipment from electromagnetic radiation. The effects of various weight percentages of barium ferrite nanoparticles on the microstructure, phase, magnetic characteristics, and wave absorption were investigated. The XRD, FTIR, Raman spectroscopy, X-ray Photoelectron spectroscopy (XPS), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), FESEM, and vibrational magnetometry (VSM) and the vector network analyzer (VNA) were used to characterize the sample.Results show that barium ferrite nanoparticles had a saturation magnetization of 42.94 emu/g, whereas graphene oxide aerogel composite containing 67 wt% of barium ferrite nanoparticles had a saturation magnetization of 29 emu/g. The Coercivity of the composite rose when the amount of barium ferrite nanoparticles was reduced. Within the matched frequency of 12.1 GHz and an effective absorption bandwidth (RL < −10 dB) of 2.6 GHz, the graphene aerogel nanocomposite sample with a thickness of 4 mm and 40 wt% of barium ferrite nanoparticles had the highest level of reflection loss (−43 dB)