The improved magnetic properties in phosphorus substituted Pr–Fe–P–B nanocomposites

Abstract

Phosphorus substituted (Pr,Tb)8(Fe,Nb,Zr,P)88B4 nanocomposites have been produced by melt-spinning. The effects of phosphorus substitution as well as wheel speed on the crystallization behavior and magnetic properties of the melt-spun samples have been investigated. With the substitution of phosphorus, the crystallization temperature of amorphous phase increases. The optimum wheel speed was found to be around 25 m/s for as-spun ribbons and 40 m/s for the annealed samples, both of which present excellent second quadrant hysteresis loop shapes due to the fine grain size of α-Fe which is around 20 nm. The addition of phosphorus also greatly improves the coercivity of Pr–Fe–B nanocomposites without a significant loss of saturation magnetization. A higher coercivity of 9.2 kOe in P-substituted samples was obtained as compared to 8.1 kOe in P-free samples. This is attributed to a narrower temperature span between the crystallization into TbCu7 structure and the transformation into the 2:14:1 phase caused by the phosphorus substitution.

Magnetic properties of Pr-Fe-Co-B bonded HDDR magnets with alloying additions

“…The remanence of the Pr 14 Fe bal Co 16 B 6 Nb 0.1 P 0.1 magnet was much higher than that of the Pr 14 Fe bal Co 16 B 6 Nb 0.1 magnet, showing that the combination Nb/P was very efficient to induce high anisotropy. The addition of P to an alloy (Pr 7 Tb 1 Fe 87-x Nb 0.5 Zr 0.5 P x B 4 ) prepared by melt-spinning led to the formation of a Pr-P phase 22 . This diminished the melting point of the alloy and refined the alloy microstructure.…”

Coercivity Mechanism and Magnetization Reversal Process in Nanocomposite Pr2Fe14B/α‐Fe Alloy with Phosphorous Addition

“…This can also be verified by the lower Hc of nanocomposite magnets than that of corresponding single‐hard‐phase magnets. [ 12 ] Fisher et al [ 26 ] also reported that the coercivity field of uncoupled magnets is larger than exchange‐coupled magnets, taking into account the exchange coupling of the grains. With further increase of P addition ( x = 0.5), the volume fraction of amorphous phase is subsequently increased, and the grain size of 2:14:1 phase is also decreased (around 16 nm).…”

“…It has been reported that P addition in Pr–Tb–Fe–Nb–B–Zr alloy raises the coercivity value from 650 to 732 kA m −1 . [ 12 ] Substitution of B by 5 at% P in Fe 55 Pt 25 B 20 ribbon can increase the volume fraction of hard magnetic and amorphous phases and increase coercivity value from 533 to 962 kA m −1 . [ 13 ] In Nd 9.5 Fe 84 B 6.5 alloy system, 0.1 at% P addition can achieve remanence value up to 1.18 T and (BH) max value of 190 kJ m −3 along the direction perpendicular to the ribbon plane.…”