Grant-in-Aid for General Scientific Research (B)
|Allocation Type||Single-year Grants |
|Research Institution||CHUBU UNIVERSITY |
NARITA Kenji CHUBU UNIV., ELECTRICAL ENGINEERING, PROF., 工学部, 教授 (90037664)
FUKUNAGA Hirotoshi NAGASAKI UNIV., ELECTRICAL ENGINEERING, ASSOC. PROF., 工学部, 助教授 (10136533)
TERADA Hiroshi CHUBU UNIV., ELECTRICAL ENGINEERING, LECTURER, 工学部, 講師
KATO Akira CHUBU UNIV., MECHANICAL ENGINEERING, ASSOC. PROF., 工学部, 助教授 (00113085)
MIYAZIMA Sasuke CHUBU UNIV., APPLIED PHYSICS, PROF., 工学部, 教授 (80029173)
|Project Period (FY)
1988 – 1989
Completed (Fiscal Year 1989)
|Budget Amount *help
¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 1989: ¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1988: ¥3,300,000 (Direct Cost: ¥3,300,000)
|Keywords||Rapid quenching / Rapid microcrystalization / High coercive ribbons / Amorphous rare-earth Iron Boron ribbons / NdーFeーBアモルファス薄帯 / 瞬間結晶化 / Nd-Fe-Bアモルファス薄帯|
(1) Mn-Al-B and Al-Ni-Co-B Ribbon Magnets
Magnets is not obtainable for Mn-Al-B alloy by rapidly crystallized techniques, The coercivity of 600 Oe, however, turns to be out of Fe-Ni-Co-Cu-B amorphous ribbons by the 700ﾟC rapidly crystallized processing.
(2) R-Fe-B Microcrystallized Amorphous Ribbon Magnets
(2.1) Automatic High-magnetic-field Impulse Measurement of Demagnetization Curves
The system that demagnetization curves of magnets with super-high coercivities are automatically measured by applying a high impulsed magnetic field of 7-8 T on the sample has been completed so that it becomes possible to measure automatically them.
(2.2) Crystallization of Amorphous Ribbon without Applied Magnetic Field
In a viewing of the shapes of virgin magnetization curves of samples, it has been shown that pinning mechanism prevails in determining the coercivity of magnets with low containing of elements Nd and B, and that the coercivity is dominated by nucleation mechanism for the comparatively Nd,B-ri
ch magnets. The coercivity of the latter is above 15KOe.Because the remanence of ribbons is perpendicularly larger than it is longitudinally, it could be concluded that crystallization aligns in a perpendicular direction.
(2.3) Crystallization of Amorphous Ribbon within Applied Magnetic Field
It is shown in Nd-(Fel-xCox)-B ribbon magnets that these magnets features in high Curie temperature larger than their crystallized temperatures while x is greater than 0.4, and a coercivity greater than 10 KOe is obtained while x less than 0.6. Remanence will increase by 30% by means of crystallization of amorphous ribbons within applied magnetic field.
(2.4) Analysis of Magnetization Process
As a results of computer calculation of the influences of decrease in both anisotropic and exchange constants at the crystalline boundaries of Nd2Fe14B in Nd-Fe-B systems on the magnetization process, we could come to conclusions that (a) if only anisotropic constant gets decreased while the size of inhomogeneities remains less than 1.40 A, coercivity is determined by nucleation mechanism and, (b) if the exchange constant gets less and less, there is almost no effects imposed on nucleation field. Less