Magnetic property enhancement and characterization of nano-structured barium ferrite by mechano-thermal treatment
- School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box: 14395-553, Tehran (Iran, Islamic Republic of)
- Ceramic Department, Materials and Energy Research Center, Karaj (Iran, Islamic Republic of)
- Nanostructured Materials (NSM), Faculty of Applied Sciences, Delft University of Technology, Julianalaan 136, 2628 BL Delft (Netherlands)
- National Center for HREM, Kavli Institute of Nanoscience, Delft University of Technology, Rotterdamseweg 137, 2628 AL, Delft (Netherlands)
- Electricity and Electronics Department, Basque Country University UPV/EHU, P.O. Box: 644, 48080 Bilbao (Spain)
In this research a mixture of barium ferrite and graphite powders was milled in a planetary ball mill and then heat treated in vacuum to produce BaFe{sub 12}O{sub 19}/Fe{sub 3}O{sub 4} and Fe/Fe{sub 3}O{sub 4} magnetic nano-composites. The effects of milling time and heat treatment temperature on the characteristics of powder mixture were investigated by X-ray diffraction analysis, vibrating sample magnetometer, transmission electron microscopy and Moessbauer spectroscopy. Phase analysis results showed that Fe{sub 2}O{sub 3} in barium ferrite partially reduced to Fe{sub 3}O{sub 4} during milling; hence, the reduced phase and remaining barium ferrite formed a nano-composite of BaFe{sub 12}O{sub 19}/Fe{sub 3}O{sub 4} after 20 h of milling. Heat treatment of the 40 h milled samples at 750-900 Degree-Sign C resulted in formation of Fe containing nano-composite. Magnetic measurements indicated that the coercivity of 267.92 Oe for 40 h milled sample decreased to 22.57 Oe by heat treatment at 900 Degree-Sign C, while its saturation magnetization increased from 31.56 to 169.43 emu/g due to the formation of Fe nano-crystallites. - Highlights: Black-Right-Pointing-Pointer Barium hexaferrite and graphite were treated mechano-thermally. Black-Right-Pointing-Pointer After 20 h milling, a nano-composite of BaFe{sub 12}O{sub 19}/Fe{sub 3}O{sub 4} formed. Black-Right-Pointing-Pointer Heat treatment of milled sample resulted in formation of Fe/Fe{sub 3}O{sub 4} composite. Black-Right-Pointing-Pointer Increasing heat treatment temperature results in higher saturation magnetization. Black-Right-Pointing-Pointer The milled and heat treated samples were nano-crystalline.
- OSTI ID:
- 22066410
- Journal Information:
- Materials Characterization, Vol. 63, Issue Complete; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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