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Bismuth ferrite (BiFeO3) nanocomposites were synthesized using a novel nano-agitator bead milling method followed by calcination. Bismuth oxide and iron oxide nanoparticles were mixed in a stoichiometric ratio and milled for 3 h and calcined at 650 °C in air. X-ray diffraction with Rietveld refinement, scanning electron microscopy, and transmission electron microscopy techniques were used to elucidate the structure of BiFeO3. The particle diameter was found to be ∼17 nm. Magnetic and electrical measurements were performed, and these results were compared with those of similar methods. Mostly, BiFeO3 was obtained with minor secondary phase formation. The resulting powder was weakly ferromagnetic with a remnant magnetization of 0.078 emu/g. This can be attributed to residual strain and defects introduced during the milling process. Electrical testing revealed a high leakage current density that is typical of undoped bismuth ferrite.
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Effect of Ball Milling on the Magnetic Performance of Strontium Ferrite (SrFe12O19) Powders
The primary advantage of the high energy ball milling (HEBM) process is its ability to synthesize a homogeneous mixture with submicron (up to nanoscale) particle size. This approach is a viable process for particle size reduction and grain refinement of magnetic powders, which affects their domain structure and by extension the resulting magnetic properties. In this research, we designed a 9-ball milling experiment by keeping the rotational speed constant at 300rpm and varying the ball-to-powder ratio of 5:1, 8:1, and 10:1 for 6hrs, lOhrs, and 14hrs milling times. The strontium ferrite magnetic powders subjected to HEBM were analyzed for crystallite size and behavior via XRD, particle size reduction via SEM/ImageJ software/originLabPro, and magnetic performance via powder-based VSM measurement. The magnetic performance of the ball-milled strontium ferrite powders shows a good combination of appreciable increment in the S-values (a ratio of the remanence to saturation magnetization) and a considerable decline in coercivity (<10% decrease) at 6hrs of milling duration. The particle size obtained at 6hr-8:1BPR is 0.59 µm with about 44% reduction from the 1.05 µm particle size of the unmilled strontium ferrites, which is within the reported single-domain particle critical size (0.5 µm - 0.65 µm). The particle size reduction of 0.59 µm at 6hr-8: lBPR would be beneficial in enabling strong interfacial bonding when the ballmilled strontium ferrite powders are used in polymer-bonded magnets.
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- Award ID(s):
- 2216440
- PAR ID:
- 10539439
- Publisher / Repository:
- NA SAMPE
- Date Published:
- ISBN:
- 978-1-934551-45-5
- Subject(s) / Keyword(s):
- Strontium ferrite, High Energy Ball Milling, Milling Parameters, Magnetic domain structure - single and complex, Vibrating Sample Magnetometer
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.33599/nasampe/s.24.0225
