TY - JOUR
T1 - Magnetic properties on bulk exchange-spring magnets in Nd-Fe-Co-V-B system formed by Spark Plasma Sintering
AU - Ono, Hideaki
AU - Shimada, Munekatsu
AU - Fujiki, Akira
AU - Yamamoto, Hiroshi
AU - Sonoda, Masayuki
AU - Tani, Masato
PY - 2000/6
Y1 - 2000/6
N2 - Bulk exchange-spring magnets of Nd11Fe72Co8V1.5B7.5 and Nd9Fe76Co8V1B6 alloys were prepared by Spark Plasma Sintering (SPS) using the rapidly quenched ribbon powders. The effects of SPS process conditions on magnetic properties and structures were investigated. SPS is a type of solid compression sintering similar to hot-pressing (HP) and can be performed at lower temperature with a shorter holding time. Bulk magnets reached to approximately full density at a sintering temperature of higher than 650 °C for 5 min. and had magnetically isotropic properties. They indicated the spring back phenomenon peculiar to exchange-spring magnets and consisted of multiphase of the Nd2Fe14B type phase and the α-Fe type phase. Grain growth did not occurred between the powders of the starting ribbons, but the fine crystals were observed inner the powders of the ribbons with an increase in the sintering temperature. Optimum preparation conditions and magnetic properties were as follows: composition, Nd9Fe76Co8V1B6; surface velocity of the roller during melt spinning for starting ribbons, Vs = 20 m/s; SPS condition, at 675 °C for 5 min. under 490 MPa; magnetic and other properties, Bt = 0.99 T, HcJ = 415 kA/m, (BH)max = 107.8 kJ/m3, Hk/HcJ×100 = 23%, spring back ratio = 40% and D = 7.59 Mg/m3.
AB - Bulk exchange-spring magnets of Nd11Fe72Co8V1.5B7.5 and Nd9Fe76Co8V1B6 alloys were prepared by Spark Plasma Sintering (SPS) using the rapidly quenched ribbon powders. The effects of SPS process conditions on magnetic properties and structures were investigated. SPS is a type of solid compression sintering similar to hot-pressing (HP) and can be performed at lower temperature with a shorter holding time. Bulk magnets reached to approximately full density at a sintering temperature of higher than 650 °C for 5 min. and had magnetically isotropic properties. They indicated the spring back phenomenon peculiar to exchange-spring magnets and consisted of multiphase of the Nd2Fe14B type phase and the α-Fe type phase. Grain growth did not occurred between the powders of the starting ribbons, but the fine crystals were observed inner the powders of the ribbons with an increase in the sintering temperature. Optimum preparation conditions and magnetic properties were as follows: composition, Nd9Fe76Co8V1B6; surface velocity of the roller during melt spinning for starting ribbons, Vs = 20 m/s; SPS condition, at 675 °C for 5 min. under 490 MPa; magnetic and other properties, Bt = 0.99 T, HcJ = 415 kA/m, (BH)max = 107.8 kJ/m3, Hk/HcJ×100 = 23%, spring back ratio = 40% and D = 7.59 Mg/m3.
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U2 - 10.2497/jjspm.47.667
DO - 10.2497/jjspm.47.667
M3 - Article
AN - SCOPUS:0034204726
SN - 0532-8799
VL - 47
SP - 667
EP - 673
JO - Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
JF - Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy
IS - 6
ER -