The production and characterisation of highly anisotropic PrFeCoB-type HDDR powders

The effect of niobium content on the magnetic properties and microstructures of PrFECoBNb HDDR magnets and alloys

“…All the alloys contain about 0.1 wt% aluminium as an impurity (as per the supplier's specification). Details of HDDR magnet production, heat treatments to homogenize the alloy and magnetic measurements have been described in previous papers [1][2][3][4][5][6][7]. Permeameter measurements were performed after saturation in a pulsed field of 6.0 T. Remanence values were normalized assuming 100% density for the HDDR sample, and by considering a linear relationship between density and remanence.…”

“…Additions of niobium and zirconium are necessary to develop optimum anisotropic magnetic properties in praseodymium-based magnets produced by the hydrogenation, disproportionation, desorption and recombination (HDDR) process [1][2][3][4][5][6][7][8][9][10][11]. Powders based on the composition Pr 13.7 Fe 63.5 Co 16.7 B 6 Nb 0.1 can be produced with good remanence (B r $ 1 T) and reasonable intrinsic coercivity ( i H c $ 0:8 MA m À1 ) [3].…”

Effects of additives on hydrogen absorption and desorption characteristics of Nd(Fe,Mo)12 alloys

“…The recent results show that the formation of anisotropy in the HDDR ternary R 2 Fe 14 B material may differ from that in HDDR R 2 Fe 14 B materials with the additives. The addition of Co, Zr, Nb, or Ga is helpful for preparing anisotropic HDDR R 2 Fe 14 B-type powders [2][3][4], and it is found that some intermediate phase existing in their disproportionated products is the key to the formation of anisotropy [5][6][7]. Since the HDDR phenomena in the Nd(Fe,Mo) 12 alloys are very similar to those in R 2 Fe 14 B [8,9], it is possible to produce anisotropic Nd(Fe,Mo) 12 N X powders by the addition of additives.…”

Effect of boron content on magnetic properties and microstructure of PrFeCoBNb HDDR permanent magnets

“…Over the past five years, extensive research has been done to study Pr-Fe-Co-B-type magnets obtained by the hydrogenation, disproportionation, desorption and recombination (HDDR) process [1][2][3][4][5][6][7][8][9][10]. Recently, it was shown that the amount of cobalt (Pr 14 Fe 79.9Àx Co x B 6 Nb 0.1 ) has a significant influence on the microstructure of magnetic alloys and on the properties of HDDR magnets [11].…”