• Title/Summary/Keyword: HDDR

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EFFECT OF THE MICROSTRUCTURE ON MAGNETIC PROPERTIES OF $Nd_{2}(Fe,Co)_{14}B_{1}Ga$-BASED ALLOYS DURING HDDR PROCESS

  • Jeung, W.Y.;Lee, S.H.;Vintaikin, B.E.
    • Journal of the Korean Magnetics Society
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    • v.5 no.5
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    • pp.408-411
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    • 1995
  • Microstructure and magnetic properties of $Fe-Nd_{13.5}-Co_{15}-B_{6-8}Ga_{0-1}-Zr_{0.2-1}$ alloys during HDDR process were studied. $ZrB_{2}$ phase was detected and identified by X-Ray diffraction. Influence of Ga, Zr and Ga+Zr additions on phase relations at different stages of HDDR process was studied by X-ray diffraction and magnetic measurements.

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Effect of Grain Boundary Modification on the Microstructure and Magnetic Properties of HDDR-treated Nd-Fe-B Powders

  • Liu, Shu;Kang, Nam-Hyun;Yu, Ji-Hun;Kwon, Hae-Woong;Lee, Jung-Goo
    • Journal of Magnetics
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    • v.21 no.1
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    • pp.51-56
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    • 2016
  • The microstructure and magnetic properties of HDDR-treated powders after grain boundary diffusion process (GBDP) with Nd-Cu alloy at different temperatures have been studied. The variation of GBDP temperature had multifaceted influences on the HDDR-treated powders involving the microstructure, phase composition and magnetic performance. An enhanced coercivity of 16.9 kOe was obtained after GBDP at $700^{\circ}C$, due to the modified grain boundary with fine and continuous Nd-rich phase. However, GBDP at lower or higher temperature resulted in poor magnetic properties because of insufficient microstructural modification. Especially, the residual hydrogen induced phenomenon during GBDP strongly depended on the GBDP temperature.

Texture Study in HDDR-treated Nd-Fe-B-type Particles

  • Kim, Jung-Hwan;Kwon, H.W.
    • Journal of Magnetics
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    • v.10 no.4
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    • pp.152-156
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    • 2005
  • Effects of the disproportionating hydrogen pressure and alloy composition on the texture in the HDDR-treated Nd-Fe-B particles were examined using the $Nd_{12.6}Fe_{81.4}B_6$ and $Nd_{12.6}Fe_{68.7}B_6Co_{11.0}Ga_{1.0}Zr_{0.l}$ alloys. Disproportionation kinetics of the $Nd_2Fe_{14}B$ phase in the Nd-Fe-B alloy was retarded significantly by the addition of Co, Ga and Zr. The retarded disproportionation kinetics of the $Nd_2Fe_{14}B$ phase ensured a wider processing win­dow in terms of disproportionating hydrogen pressure for achieving a texture in the HDDR-treated Nd-Fe-B alloy particles.