The cellular precipitation microstructure of 2:17-type magnetic compound was studied at various states of aging by transmission electron microscopy. It was shown that, the initial supersaturated solid solution phase (1175°C, 50 hours) exerts a great influence on the precipitation behavior in the subsequent isothermal aging process. When the supersaturated phase was a TbCu7-type disordered structure, it gives rise to a fine-scale continuous cellular precipitation microstructure which corresponds to a relatively high coercivity state. The cell interior is a Th2Zn17-type 2:17 phase which is separated by a thin continuous 1:5 boundary phase. On the other hand, when the supersaturated phase was Th2Zn17-type ordered structure, it only produces particle-like 1:5 phase precipitates along the large grain boundary of the Th2Zn17-type 2:17 phase, which corresponds to a very low coercivity state. An addition of copper stabilizes the TbCu7-type disordered phase, and therefore increases the coercivity.
|Number of pages||15|
|Journal||Memoirs of the Faculty of Engineering, Hokkaido University, Sapporo, Japan|
|Publication status||Published - 1989 Dec 1|
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