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Characterization of the Microstructure of Gas-atomized Nd-Fe-B Alloy Particles of Non-peritectic Chemical Compounds

Gao, J. and Volkmann, T. and Reutzel, S. and Herlach, D.M. (2005) Characterization of the Microstructure of Gas-atomized Nd-Fe-B Alloy Particles of Non-peritectic Chemical Compounds. Journal of Alloys and Compounds, 388 (2), pp. 235-240. DOI: 10.1016/j.jallcom.2004.07.027.

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Abstract

Gas-atomized Nd-Fe-B droplets of non-peritectic chemical compositions Nd<sub>16</sub>Fe<sub>76</sub>B<sub>8</sub>, Nd<sub>17</sub>Fe<sub>74.5</sub>B<sub>8.5</sub>, and Nd<sub>18</sub>Fe<sub>73</sub>B<sub>9</sub> were undercooled and solidified in an 8-m drop tube filled with helium. The microstructure of the received particles was investigated by means of scanning electron microscopy and powder X-ray diffractometry. It was found that in each alloy composition, in excess of 71% of the particle population shows a microstructure comprising primary Nd<sub>2</sub>Fe<sub>17</sub>B<sub>x</sub> dendrites plus interdendritic Nd<sub>2</sub>Fe<sub>14</sub>B grains plus intergranular Nd<sub>1.1</sub>Fe<sub>4</sub>B<sub>4</sub> and Nd-rich grains, where the metastable Nd<sub>2</sub>Fe<sub>17</sub>Bx dendrites are partially or completely decomposed into a mixture of <font face="Symbol">g</font>-Fe plus Nd<sub>2</sub>Fe<sub>14</sub>B depending on particle size. There is often a certain amount of Nd<sub>2</sub>Fe<sub>14</sub>B dendrites in these particles, resulting in a dual microstructure. On the other hand, the rest of the particle population shows a microstructure consisting of primary Nd<sub>2</sub>Fe<sub>14</sub>B grains, either columnar or dendritic, plus intergranular Nd<sub>1.1</sub>Fe<sub>4</sub>B<sub>4</sub> and Nd-rich phase grains. Additionally, a tiny amount of <font face="Symbol">g</font>-Fe dendrites is formed in some of the particles independent of the type of the microstructure. They are exclusively distributed near the particle surface, and are surrounded either by Nd<sub>2</sub>Fe<sub>14</sub>B grains or by Nd<sub>2</sub>Fe<sub>17</sub>B<sub>x</sub> grains in individual particles.

Document Type:Article
Additional Information: LIDO-Berichtsjahr=2005,
Title:Characterization of the Microstructure of Gas-atomized Nd-Fe-B Alloy Particles of Non-peritectic Chemical Compounds
Authors:
AuthorsInstitution or Email of Authors
Gao, J.Northeastern University, Shenyang, China
Volkmann, T.UNSPECIFIED
Reutzel, S.Ruhr-Universität Bochum
Herlach, D.M.UNSPECIFIED
Date:2005
Journal or Publication Title:Journal of Alloys and Compounds
Refereed publication:Yes
In ISI Web of Science:Yes
Volume:388
DOI:10.1016/j.jallcom.2004.07.027
Page Range:pp. 235-240
Status:Published
Keywords:Unterkühlung von Materialien
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W FR - Forschung unter Weltraumbedingungen (old)
DLR - Research area:Space
DLR - Program:W FR - Forschung unter Weltraumbedingungen
DLR - Research theme (Project):W - Vorhaben Materialwissenschaftliche Forschung (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Materials Physics in Space > Institute of Space Simulation > Center for Solidification of Undercooled Melts (ZEUS)
Deposited By: Astrid Herrmann
Deposited On:13 Jun 2006
Last Modified:14 Jan 2010 15:17

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