Corroded microstructure of HDDR-NdFeB magnetic powders

L. Y. Zhu, M. Itakura, Y. Tomokiyo, N. Kuwano, K. Machida

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


The microstructure of corroded HDDR-NdFeB magnetic powders in bonded magnet has been investigated by transmission electron microscopy. Following an exposure time of 300h at 398K in air, the HDDR-NdFeB magnetic powders are found covered with an altered layer about 300nm thick on the surface. The layer is composed of α-Fe grains 5-10nm in diameter and h-Nd2O 3 grains smaller than 5nm. Under the altered layer, corrosion has proceeded along the Nd2(Fe,Co)14B grain boundaries to leave a wetting layer composed of a dense mixture of α-Fe and h-Nd 2O3 phase. The appearance of α-Fe grains in both of the altered layer wetting layer leads to the high magnetic flux loss of the corroded HDDR-NdFeB bonded magnet.

Original languageEnglish
Pages (from-to)353-358
Number of pages6
JournalJournal of Magnetism and Magnetic Materials
Issue number2-3
Publication statusPublished - Aug 2004

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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