Papers by Keyword: α-Fe

Abstract: In order to fabricate flake-shaped core-shell micro particles (FCMP) with light weight efficiently, deposition on diatomite was carried out by thermal decomposition. The deposition of Fe on diatomite was accomplished by thermal decomposition of pentacarbonyl iron (Fe(CO)₅). The scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) are used to make clear their morphology microstructure, chemical composition, and crystal structure. The average diameter of FCMP is around 40μm, and the average aspect ratio is over 15. The main chemical composition of the FCMP is Fe, Si, Oand C. The XRD result revealed that crystal structures of the FCMP is close to α-Fe. The vibrant sample magnetometer (VSM) result revealed that the FCMP belong to soft magnetic material. The density test results show that the density of FCMP is close to the 2.6, which is lower than the density of pure carbonyl iron powder.

Abstract: The impurity diffusion coefficients of Cu in Fe have been determined in the temperature range of 1073 - 1163 K by means of Laser Induced Breakdown Spectrometry (LIBS). The volume diffusion coefficients for Cu impurity diffusion in a-iron found in this work are in good agreement with the previously published result. The grain boundary diffusion coefficient gb D s d was also calculated using the volume diffusivity and processing the tails of the measured profiles. The values of the activation energy for volume and grain boundary diffusion were approximately 280 and 161 kJmol-1, respectively. This indicates the possibility of a monovacancy diffusion mechanism in case of volume diffusion. The results for the diffusion coefficients are Dv= 2.2 ×10-2exp(-280 kJmol-1/RT) m2s-1 and gb D s d = 2.6 ×10-11exp(-161 kJmol-1/RT) m3s-1.