Magnetic properties of Nd-Fe-Co-Cu-Nb-B system exchange-spring magnets

✍ Scribed by Hiroshi Yamamoto; Toru Niinomi; Satoshi Koumo; Masaaki Hamano; Minoru Yamasaki

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 552 KB
• Volume: 133
• Category: Article
• ISSN: 0424-7760
• DOI: 10.1002/1520-6416(20001130)133:3<1::aid-eej1>3.0.co;2-8

✦ Synopsis

The amorphous melt-spun ribbons of Nd-Fe-Co-Cu-Nb-B system alloys were prepared by single-roller rapidquenching method. The effects of composition, wheel velocity, and heat treatment on the magnetic properties were investigated. The amorphous Nd 9 Fe 75.5 Co 8 Cu 0.5 Nb 1 B 6 ribbon prepared at a wheel velocity of 15.0 m/s was crystallized by heat treatment, and the optimum heat-treatment condition was found to be 700 °C for 5 min, at which the value of (BH) max was 114.8 kJ/m 3 . The temperature coefficients of J r and H cJ for the ribbons crystallized from the amorphous Nd 9 Fe 75.5 Co 8 Cu 0.5 Nb 1 B 6 alloy were DJ r 0.064%/°C (reversible) and E(H cJ ) = 0.426%/°C (irreversible). The value of (BH) max for the compression molding Nd 9 Fe 75.5 Co 8 Cu 0.5 Nb 1 B 6 isotropic bonded magnet prepared by using the ribbons annealed at 700 °C for 5 min is 78.66 kJ/m 3 and the density is 6.23 Mg/m 3 .