放電プラズマ焼結法により作製したナノ結晶Fea_0Zr_7B_3バルク材の軟磁気特性 Soft Magnetic Properties of Bulk Nanocrystalline Fea_0Zr_7B_3 Alloys Consolidated by Spartk-Plasma Sintering
Nanocrystalline bulk Fe<SUB>90</SUB>Zr<SUB>7</SUB>B<SUB>3</SUB> alloys with grain sizes of 20 to 30 nm were prepared by spark-plasma sintering of amorphous powders and subsequent annealing. The bulk alloys sintered at the temperature (<I>T<SUB>s</SUB></I>) between 673 and 723 K are composed of a mostly single amorphous phase and the alloy sintered at <I>T<SUB>s</SUB></I> of 873 K is composed of a mostly single bcc-Fe phase in as-sintered state. The former alloys show better soft magnetic properties in spite of porous consolidated state than the latter alloy after annealing at 923 K. For the bulk alloy sintered at <I>T<SUB>s</SUB></I> of 723 K, the effective permeability (μ<SUB>e</SUB>) increases by accelerating the heating rate (α) in sintering and the density becomes higher by increasing the sintering pressure (<I>P<SUB>s</SUB></I>). The nanocrystalline alloy sintered at <I>T<SUB>s</SUB></I> of 723 K, <I>P<SUB>s</SUB></I> of 780 MPa and α of 1.7 K/s shows the maximum permeability of 29800, effective permeability of 3430 at 100 Hz and coercivity of 12 A/m with a relative density of 97 %.
粉体および粉末冶金 43(5), 613-618, 1996-05-15
Japan Society of Powder and Powder Metallurgy