Fabrication and Characterization of Magnetic Nanocomposite Powders in Hematite-Ca System by Mechanical Alloying

Abstract:

We have applied mechanical alloying technique to produce magnetic nanocomposite material using a mixture of Fe₂O₃ and Ca powders at room temperature. An optimal ball milling and heat treatment conditions to obtain magnetic α-Fe/CaO composite with fine microstructure were investigated by X-ray diffraction, scanning electron microscope and vibrating sample magnetometer measurements. We have revealed that the magnetic α-Fe /CaO nanocomposite powders can be produced by solid state reduction during ball milling. It is found that α-Fe/CaO nanocomposite powders in which CaO is dispersed in α-Fe matrix with a grain size of 45 nm are obtained by mechanical alloying of Fe₂O₃ with Ca for 5 hours. The saturation magnetization of ball-milled powders increases with increasing milling time and reaches to a maximum value of 65 emu/g after 7 hours of MA. The average grain size of a-Fe in 5 hours MA powders estimated by diffraction line-width are gradually decreased with increasing milling time, and tend to reach at 45 nm. The magnetic hardening due to the reduction of the α-Fe grain size by MA is also observed.

• Periodical: Key Engineering Materials (Volume 753)
• Pages: 78-83
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.753.78
• Online since: August 2017
• Authors: Chung Hyo Lee*
• Keywords: Magnetic Composite Powders, Mechanical Alloying, Saturation Magnetization, Solid State Reduction

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