Influence of RE-rich phase distribution in initial alloy on anisotropy of HDDR powders

The influence of the RE-rich phase distribution in the precursor alloys on the anisotropy of the hydrogenation disproportionation desorption recombination (HDDR) processed powders is investigated. The homogenized ingot alloy and the as-cast strip casting (SC) alloy with a uniform RE-rich grain boundary phase lead to high anisotropy of the refined powders, acquiring degrees of alignment (DOA) of 0.62 and 0.54, respectively. The RE-rich phase aggregation results in a deteriorated DOA of the powders due to the drastic disproportionation rate, while a thin and uniform RE-rich phase distribution is beneficial for DOA. A reaction model of the initial particle microstructure is proposed for optimizing the HDDR powder anisotropy.

[1]  L. Schultz,et al.  Structural and magnetic properties of heat-treated ultrafine single crystalline Nd2Fe14B particles obtained by ball-milling of dynamic hydrogenation disproportionation desorption and recombination powder , 2014 .

[2]  Yu Yan,et al.  Processing YCo 5 Permanent Magnetic Submicron Flakes by Surfactant-Assisted High-Energy Ball Milling , 2012 .

[3]  M. Sagawa,et al.  Microstructure of fine-grained Nd–Fe–B sintered magnets with high coercivity , 2011 .

[4]  Yingchang Yang,et al.  Self-organized rod-like nanostructure in Pr2Fe14B-type alloy and its role in inducing texture during the early stages of disproportionation , 2011 .

[5]  H. Sepehri-Amin,et al.  Coercivity enhancement of HDDR-processed Nd–Fe–B permanent magnet with the rapid hot-press consolidation process , 2011 .

[6]  G. Han,et al.  Anisotropic HDDR Nd–Fe–B magnetic powders prepared directly from strip casting alloy flakes , 2009 .

[7]  H. Kwon,et al.  Effect of hydrogen pressure on disproportionation kinetics of Nd–Fe–B alloy , 2009 .

[8]  T. Ohkubo,et al.  The role of grain boundaries in the coercivity of hydrogenation disproportionation desorption recombination processed Nd–Fe–B powders , 2009 .

[9]  Yingchang Yang,et al.  Microstructural evolutions of Pr13Fe80B7 alloys during solid HDDR process , 2007 .

[10]  H. Kwon,et al.  Effect of hydrogen pressure on anisotropy of HDDR-treated Nd–Fe–B-type powder , 2006 .

[11]  Y. Honkura,et al.  Texture memory effect of Nd Fe B during hydrogen treatment , 2005 .

[12]  K. Igarashi,et al.  Magnetic properties of anisotropic Nd–Fe–B HDDR powders prepared from strip cast alloys , 2004 .

[13]  I. R. Harris,et al.  The production and characterisation of highly anisotropic PrFeCoB-type HDDR powders , 2001 .

[14]  K. Morimoto,et al.  Anisotropic Nd–Fe–B bonded magnets made from HDDR powders (invited) , 1996 .

[15]  I. R. Harris,et al.  Nd-Fe-B Permanent Magnets: Hydrogen Absorption/Desorption Studies (HADS) on Nd16Fe76B8 and Nd2Fe14B , 1987 .

[16]  I. R. Harris,et al.  The hydrogen decrepitation of an Ndi15Fe77B8 magnetic alloy , 1985 .