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

Eguiberto Galego,Hidetoshi Takiishi,Rubens Nunes De Faria Jr

doi:10.1590/s1516-14392007000300010

Abstract

Microstructures and magnetic properties of Pr-Fe-Co-B bonded magnets were investigated. The magnets can be represented by the formulae, Pr14Fe63.9Co16B6M 0.1 (M = Ti, V, Cr, Ni, Zr, Nb or Mo), Pr14Fe63.8Co16B6Nb 0.1T0.1 (T/= Al, Si, P, Cu or Ga) and Pr14Fe63.6Co16B6Nb 0.1R0.3 (R = Gd, Tb or Dy). The effects of additions on the magnetic properties of PrFeCoB-based magnets have been studied. Magnetically hard powders have been produced from homogenised alloys using the hydrogenation, disproportionation, desorption and recombination (HDDR) process. The HDDR powders were isostatically pressed and bonded with cyanoacrylate adhesive to form permanent magnets.

Highlights

Neodymium- and praseodymium-based bonded magnets can be successfully prepared by the HDDR process[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17]
The results indicate that vanadium, nickel, zirconium and niobium can be used as a single addition to Pr14FebalCo16B6 HDDR bonded magnets
Niobium and zirconium induce considerably anisotropy whereas vanadium and nickel enhance the intrinsic coercivity

Summary

Introduction

Neodymium- and praseodymium-based bonded magnets can be successfully prepared by the HDDR process[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17]. A standard HDDR process appropriated for praseodymium-based bonded magnets[11] has been used in the present work. A number of variables affect the HDDR process[4] and, it is reasonable to use processing conditions that have yielded better results in the past and seek the dopant that imparts the best magnetic properties. For the present processing conditions, that uses a straightforward HDDR treatment, finding an element that induces high anisotropy or high coercivity was considered to be very important

Experimental

Results and Discussion

The effect of Cu or Ga additions

Conclusions