Download citation:
BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks
Send citation to:

---

In this research barium hexaferrite was partially reduced with graphite or carbon black in the mechanical milling medium, to form BaFe12O19/Fe3O4 nano-composites. The resulted nano-composites were heat treated in air at 300, 350, 400 and 500 °C. The milled and heat treated samples were characterized by XRD, VSM and FE-SEM. The peaks of Fe3O4 were appeared in XRD patterns of barium hexaferrite and graphite mixture with molar ratio of C:O=0.9 after 40 hrs milling and for molar ratio of C:O=1.1 after 20 hrs milling. For barium hexaferrite and carbon black mixtures, Fe3O4 peaks were appeared after 20 hrs for molar ratios of C:O=0.9 and 1.1. This was attributed to the more activity of carbon black compared to graphite. FE-SEM images showed that 20 hrs milled samples were consisted of aggregates with mean particle size of 30 nm. Heat treatment of milled mixtures resulted in an increase in coercivity and saturation magnetization due to the elimination of carbon and reducing of residual stresses. The saturation magnetization was 50.1 emu/g for barium hexaferrite and graphite mixture after 20 hrs milling and heat treating at 400 °C and this value was 55.3 emu/g for barium hexaferrite and carbon black mixture for the same conditions. The difference in the saturation magnetization was attributed to the amount of magnetite phase in the composites.

Keywords: Barium ferrite, mechanical milling, heat treatment, magnetic properties

Full-Text [PDF 379 kb]   (1901 Downloads)    

Add your comments about this article : Your username or Email:

---