Microstructure and Magnetic Properties of NdFeB Magnets Using Fluorides Nano-Coated Process
Nd2Fe14B magnets could be sintered using terbium fluoride coated Nd2Fe14B powders. Fluorine atoms were segregated at the triple junctions and grain boundary after sintering and aging process. NdOF with fcc structure was grown at the triple junction. Terbium atoms were also distributed near grain boundaries by interdiffusion between the fluoride and Nd2Fe14B. No fluorine atoms were detected in Nd2Fe14B phase. The coercivity for 0.5wt% terbium fluoride coated magnet showed 1.23 MA/m which was 1.2 times higher than that for non-coated magnet with 1.04MA/m. The distribution of terbium and fluorine atoms increases the coercivity without reduction of remanence.
T. Chandra, N. Wanderka, W. Reimers , M. Ionescu
M. Komuro et al., "Microstructure and Magnetic Properties of NdFeB Magnets Using Fluorides Nano-Coated Process ", Materials Science Forum, Vols. 638-642, pp. 1357-1361, 2010