Papers by Author: Z. Hamlati

Abstract: Ternary Fe₇₂Al₂₆Sn₂ and Cu₇₀Fe₁₈Co₁₂ alloys were obtained by mechanical alloying of pure Fe, Al, Sn, Cu and Co powders using a high energy ball mill. X-ray diffraction and electron microscopy supported by magnetic measurements have been applied to follow changes in the microstructure, phase composition and magnetic properties in dependence on milling time. With the increase of milling time all Al and Sn atoms dissolved in the bcc Fe and the final product of the MA process was the nanocrystalline Fe (Al, Sn) solid solution in a metastable state with a large amount of defects and mean crystallite size of 5 nm. However, the obtained crystallite size value is about 10 nm for the ball milled Cu₇₀Fe₁₈Co₁₂ powders. The electron microscope observations show the morphology of powder particles. Magnetic properties of the nanocrystalline mechanically alloyed FeAlSn and CuFeCo were also investigated and were related to the microstructural changes.

Abstract: In this work, we study the synthesis of Fe-Co powders via planetary ball milling with different particle sizes. The morphology is a factor that influences the microwave properties of materials. The prepared samples are characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), X-band wave guide and resonator cavity associated with network analysis. The microwave-absorbing characteristic effects are investigated in a frequency range 8.5–10.5 GHz using network analyser. They enhanced between 0 and 54 h of milling time with an increase in the relative dielectric permittivity (ε'r).

Abstract: Fe60Co40 and Fe72Al28 nano-alloys were synthesized from elemental powders via highenergy mechanical alloying. The prepared samples were characterized using X-ray diffraction, scanning electron microscopy and X-band waveguide to measure the reflection loss in a frequency range of 9-10 GHz. The XRD patterns show that disordered Fe60Co40 solid solution with a bodycentred cubic structure is formed for milling times longer than 12 h, and after 4h milling, the solid solution Fe72Al28 has been largely formed. Morphological studies indicate an average grain size of 10 to 15 nm. The microwave- absorbing characteristic reveal good performance for Fe60Co40 compared to Fe72Al28, the maximum reflection loss is about -12 dB for the absorber.