Preparation of high-power permanent magnets from platelike Nd-Fe-B alloys

Попов, А. Г.; Kudrevatykh, N. B.; Vyatkin, V. P.; Vasilenko, D. Yu.; Bratushev, D. Yu.; Puzanova, T. Z.; Gerasimov, E. G.

doi:10.1134/s0031918x10030051

Cited by 10 publications

(9 citation statements)

References 5 publications

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“…When the LOT was realized, the alloy N31 and special equipment available at the FSUE Ural Electrome chanical Plant were used. This equipment allows one to prepare powders in a jet mill and to perform the sub sequent treatment in sealed molds without any contact with air oxygen [4,5]. By varying the milling condi tions, powders with different average particle sizes (from 2.5 to 3.9 μm), which were determined by the Fisher method, were prepared.…”

Section: Introductionmentioning

confidence: 99%

Preparation of sintered Nd-Fe-B magnets by pressless process

Попов

Шитов

Gerasimov

et al. 2012

Phys. Metals Metallogr.

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Pressless process used for the preparation of sintered Nd-Fe-B magnets has been studied. The effect of the average particle size D av , filling density ρ f , and powder texturing conditions for obtaining density ρ and desired magnetic hysteretic properties of sintered magnets has been investigated for both traditional technology (TT) and low oxygen technology (LOT). The ρ f magnitude ensuring the optimum relation between the density ρ of sintered magnets and their degree of texture was shown to be 2.5-3.0 and 2.2 g/cm 3 for the TT and LOT, respectively. At lower ρ f magnitudes, no required density of sintered magnets is reached, whereas at higher filling densities, a low level of texture and low remanence are realized. Optimum param eters of pulsed field inducing the high degree of texture in powders have been determined. The following properties were achieved for magnets prepared by pressless LOT: B r ≥ 14.2 kG, H c ≥ 8 kOe, and (BH) max ≥ 47.9 MG Oe.

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Section: Introductionmentioning

confidence: 99%

Preparation of sintered Nd-Fe-B magnets by pressless process

Попов

Шитов

Gerasimov

et al. 2012

Phys. Metals Metallogr.

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“…The improvement in the degree of texture is related to changes (shown in Fig. 6) in the morphology of the powders and the par ticle size distribution, which is accompanied by a decrease in the fraction of particles with remainders of dendritic blocks 10-15 μm in size, in which the easy axes of the Nd 2 Fe 14 B grains are slightly misoriented [10]. A similar change in the ratio between the intensi ties of the (105) and (006) lines was also observed for magnets prepared with an addition of zinc stearate; therefore, the sharp decrease in B r in the magnet pre pared from a powder with D av = 2.55 μm appears to be due to the decrease in ρ noted above and a very low Н с , which decreases monotonically in this series of mag nets (see Fig.…”

Section: Effect Of Size Of Powder Particles On Properties Of Sinteredmentioning

confidence: 99%

“…The degree of texture induced by the magnetic field in the powders was esti mated using the technique described in detail in [4]. In the descending segments of the hysteresis loops of the powders, which were measured in the closed circuit of the hysteresigraph in a field of 10 kOe, the value of the magnetization 4πM was determined, which was denoted as B 10 and was used as the measure of the degree of texture. The powders were sintered directly in molybdenum containers.…”

Section: Effect Of Additions Of Zincmentioning

confidence: 99%

Effect of additions of zinc stearate on the properties of sintered Nd-Fe-B magnets

Попов

Gerasimov

Терентьев

et al. 2013

Phys. Metals Metallogr.

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Abstract-Zinc stearate additions have been used to increase the remanence of sintered Nd-Fe-B magnets produced by the powder metallurgy without powder pressing. Zinc stearate acts as an internal lubricant, i.e., it decreases the friction forces between the particles and favors an increase in the degree of texture of the pow ders, which is induced by the magnetic field. It is shown that the density and the magnetic hysteresis charac teristics of sintered magnets produced using additions of 0.15 wt % zinc stearate exceeds the corresponding values obtained for magnets produced without this addition at a filling density of powders in containers of more than 2.9 and 3.0 g/cm 3 in dry and wet states, respectively. Using additions of zinc stearate in the amount of 0.15% with respect to the weight of the powder, magnets with a density of 7.55 g/cm 3 , B r = 14.02 kG, H c = 7.91 kOe, and (BH) max = 46.1 MG Oe have been produced.

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“…The alloys were subjected to hydrogen decrepitation and rough grinding. Since, unfortunately, in this work we did not implement low-oxygen technology based on jet-milling of the powder [15], grinding of the powder was performed in a ball mill in protective fluids. Particularly, in the experiments described the toluene was used.…”

Section: Methodsmentioning

confidence: 99%