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

Barbosa, Luzinete Pereira; Takiishi, Hidetoshi; Lima, L.F.C.P.; Faria, Rubens Nunes de

doi:10.1016/j.jmmm.2004.05.032

Cited by 10 publications

(11 citation statements)

References 8 publications

(16 reference statements)

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“…If the base alloys did not contain other elements than the principal elements (Pr, Fe and B), the latter argument on the effects of very small amount of Cu addition might have sense, but the effects of Cu in such a small amount should be over-whelmed by the effects of Co and also by Pr. Previous work has shown that increase in Nb content from 0.1 to 0.5 at% decreases the B r of the magnets [28]. Increases in the amount of Cu to 0.5 at% also decreased the B r of the magnets prepared in this investigation.…”

Section: Resultssupporting

confidence: 63%

Evaluation of Mean Crystallite Size on Magnetic Powder by Scanning Electron Microscopy and Synchrotron Diffractometry

Galego¹,

Serna²,

Faria³

2014

MSA

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This paper presents the results of investigations carried out with Pr-based magnetic powders. The magnetically hard powders were produced from homogenised alloys using a high temperature hydrogen pulverization process. Alloys and powders were investigated by scanning electron microscopy and by energy dispersive X-ray analysis. Mean crystallite size of the pulverized material was estimated using synchrotron powder diffractometry and the Scherrer method. A comparison between these two investigation techniques has been carried out. The effects of copper on the properties of the magnetic powders have been studied. It has been shown that the addition of this alloying element had a marked effect on the microstructure of the powders.

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Section: Resultssupporting

confidence: 63%

Evaluation of Mean Crystallite Size on Magnetic Powder by Scanning Electron Microscopy and Synchrotron Diffractometry

Galego¹,

Serna²,

Faria³

2014

MSA

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“…More recently, it was shown that the praseodymium content (Pr x Fe 77.9Àx Co 16 B 6 Nb 0.1 ) also has a great influence in Pr-based alloys and HDDR materials [12]. Similar influence has been obtained with the niobium concentration (Pr 14 Fe 64Ày Co 16 B 6 Nb y ) in these magnets [13]. This paper reports the results of further investigations carried out on Pr 14 Fe 69.9Àx Co 16 B x Nb 0.1 alloys and magnets (x=4-8) and was undertaken to optimize the boron content in terms of the magnetic properties of the HDDR magnets.…”

Section: Introductionsupporting

confidence: 56%

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

Barbosa

Takiishi

Lima

et al. 2005

Journal of Magnetism and Magnetic Materials

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“…O hidrogênio vem sendo muito utilizado como agente pulverizador de ligas à base de terras raras e metais de transição, devido à sua taxa de difusão ser extremamente alta mesmo em temperaturas baixas. Estes materiais são usados em dispositivos de estocagem de hidrogênio, geração de eletricidade ou de campos magnéticos, que são produzidos através de um processo cuja primeira etapa é a transformação das ligas por moagem em um pó fino 2,3,4,5,6 .…”

Section: Lista De Tabelasunclassified

“…A medida de densidade hidrostática das amostras foi calculada pelo princípio de Arquimedes seguindo a Equação 1. é a densidade hidrostática (g/cm 3 ), é a massa (g) da amostra seca, é a massa (g) da amostra úmida, é a massa (g) da amostras imerssa em água e 2 é a densidade da água (g/cm 3 ).…”

Section: Caracterização Das Amostras Sinterizadasunclassified

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Caracterização mecânica e microestrutural do zircaloy-4 obtido por HD e metalurgia do pó

Cavalheira¹

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The machining step for manufacturing Zircaloy-4 (Zr-4) tubes and end caps used in pressurized water nuclear reactors (PWRs) to generate large amounts of tailings from this material. Due the high cost of the Zr-4 its requires recycling, which represents a great economy for Brazilian Nuclear policy and also avoids its disposal to the environment. In this work, the machining chips of Zr-4 were heated in the hydrogen atmosphere (923 K), and the powder from this step was sieved in the 200 and 325 mesh (<75 and <45 µm). In this stage, materials that did not absorb the hydrogen proven by the machining were removed, reducing the final contamination by Fe of the Zr-4 alloy . Grinding was performed in the high energy mill, using zirconia pot and spheres to reduce contamination. The experiments were performed at different milling times (0 to 120 min). One sample was pressed at 200 MPa (isostatic pressure) and sintered at 1423 K for 10 h. The microstructure was analyzed by scanning electron microscopy (SEM) and Vickers microhardness was determined. . The results showed that after 60 min milling the average particle size was 2.4 µm, Vickers microhardness after sintering was 425 HV and average grain size around 50 µm. The samples shown hydrostatic density values of 99% compared to the theoretical, and a microstructure shows typical morphology of phase alpha of Zr-4 and equiaxial grains. To reduce chip storage areas, a reduction of 27 times in the volume occupied by the chips after hydration, comminution and pressing was obtained. It was possible to machine the end caps from the samples with the lowest microhardness measurement.

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

Cited by 10 publications

References 8 publications

Evaluation of Mean Crystallite Size on Magnetic Powder by Scanning Electron Microscopy and Synchrotron Diffractometry

Evaluation of Mean Crystallite Size on Magnetic Powder by Scanning Electron Microscopy and Synchrotron Diffractometry

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

Caracterização mecânica e microestrutural do zircaloy-4 obtido por HD e metalurgia do pó

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