High performance α-Fe/Nd2Fe14B-type nanocomposites

Abstract

The α-Fe/R2Fe14B-type exchange-coupled NdFeB nanocomposites with a coercivity (iHc) of more than 11 kOe and energy product, (BH)max, of more than 16 MGOe have been successfully obtained on melt spun (Nd0.95La0.05)7.5+xFebalCr2B10 alloy powders, where x ranged from 3 to 3.5. It was found that a slight substitution of Cr for Fe suppresses the formation of the R2Fe23B3 and Fe3B phases during crystallization and results in the formation of an α-Fe/R2Fe14B mixture. Increasing the total rare earth content was found to enhance the remanence, and the Hic of (Nd0.95La0.05)7.5+xFe80.5−xCr2B10 ribbons was also increased drastically with increasing values of x. A Br of 9.2–9.7 kG, Hic of 11.1–13.2 kOe, and (BH)max of 16.5–18.0 MGOe have been obtained on (Nd0.95La0.05)7.5+xFe80.5−xCr2B10 (x=3–3.5).

Effect of Pr concentration on the magnetic properties and phase evolution of Ti-substituted PryFe88−yTi2B10 (y=9.5–7) nanocomposite ribbons

“…Third, the magnetic properties are better and the applicable composition range is lager in the Pr 7-9.5 Fe bal. Ti 2 B 10 nanocomposites than those of the corresponding NdFeTiB nanocomposites [22][23][24][25]. This could be due to a higher anisotropy field of Pr 2 Fe 14 B than that of Nd 2 Fe 14 B.…”

“…For further understanding the exchange coupling effect between adjacent grains in the Pr 8.5 Fe 79.5 M 2 B 10 ribbons, the Henkel plots (δM versus H) which have been successfully used by many researchers to study the nature of interactions between phases in nanocomposite magnets are employed [8,[16][17][18]. The δM is defined as m d (H) − [1 − 2m r (H)], where m d is the reduced demagnetization remanence and m r the reduced magnetization remanence [19,20].…”

Effect of substitution of refractory elements for Fe on the magnetic properties of melt-spun Pr9.5Fe80.5B10 nanocomposites

“…In addition, compared with similar compositions and Co-free in the NdFeB series nanocomposites [14,15], Pr 9.5 Fe 78.5 Nb 2 B 10 ribbons show better magnetic properties is attributed to the fact that the anisotropy field of the Pr 2 Fe 14 B phase (87 kOe) is higher than that of Nd 2 Fe 14 B phase (67 kOe). Furthermore, Pr 9.5 Fe 78.5 Nb 2 B 10 ribbons exhibit more excellent coercivity than Pr 8.5 Fe 78.5 Ti 2 B 10 ribbons [19] because of larger volume fraction of the 2:14:1 phase.…”

“…In the literature of ␣-Fe/Nd 2 Fe 14 B nanocomposites [14,15], a slight substitution of refractory elements including Cr, Nb, Ti, V and Zr has been found to be very crucial in suppressing the formation of low magnetization R 2 Fe 23 B 3 [16,17].…”

Beneficial effect of the substitution of Co for Fe on the magnetic properties of melt-spun Pr2Fe14C/α-Fe-type nanocomposite magnets

“…Due to the remanence enhancement effect arising from intergranular exchange coupling, nanocomposites consisting of magnetically hard and soft phases have been extensively studied for bonded magnets application [1][2][3]. If the intergranular exchange coupling is strong enough, the magnetic properties of nanocomposites can be enhanced by optimizing the intrinsic properties of the magnetic phases such as saturation magnetization and anisotropy field [4,5].…”