Fe/Fe$_3$O$_4$ nanocomposite powders with giant high magnetization values by high energy ball milling

[摘要] The present work reports on the relatively higher saturation magnetization values of Fe/Fe$_3$O$_4$ nanocomposites. For example, the nanocomposites of Fe obtained after milling for 10 h with 5, 10 and 15 wt% of Fe$_3$O$_4$ had displayed saturation magnetization values of 210, 238 and 216 Am$^2$ kg$^{−1}$, respectively, in contrast to 218 Am$^2$ kg$^{−1}$ of bulk Fe. Similarly, themaximum magnetization values for the nanocomposites after 20 and 30 h of milling were 215 and 190 Am$^2$ kg$^{−1}$ for the sample containing 5 and 15 wt% of Fe$_3$O$_4$, respectively. The values of $H_{\rm C}$ and $Mr$ suggest that nanocomposites exhibit soft ferromagnetic behaviour. The ball milling also reduced the crystallite and particle size of Fe from microndimension tonanometres. This was confirmed from X-ray diffraction, transmission electron microscopy and scanning electron microscopy analyses. The crystallite size of pure Fe decreased to 35, 20 and 19 nm, respectively, for the samples having 5, 10 and 15 wt% of Fe$_3$O$_4$ after 10 h of milling. The crystallite size decreased further with increased milling time.

[学科分类] 材料工程

[关键词] Nanocomposites;high energy ball mill;Fe$_3$O$_4$;magnetization.