Boron-modified 2:17-type Sm(Co,Fe,Cu,Zr)z sintered magnets

Journal Article · Tue Nov 15 00:00:00 EST 1988 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.342168· OSTI ID:6696206

Mukai, T; Fujimoto, T

The addition of a small amount of boron (8--380 ppm by weight) to the alloy with composition Co-25 wt. % Sm-19 wt. % Fe-6 wt. % Cu-2.5 wt. % Zr caused a remarkable increase in the coercive force (/sub i/H/sub c/) of the sintered magnets: /sub i/H/sub c/ = 13.7 kOe for 140-ppm B relative to /sub i/H/sub c/ = 7.1 kOe for 0-ppm B under the same aging condition. For the B-free alloy, a heterogeneous precipitation of the Cu-rich Sm/sub 2/ Co/sub 7/ -type phase (2:7 phase) was observed. The addition of B above 80 ppm completely suppressed the precipitation of the 2:7 phase. Boron was found to segregate at grain boundaries and subgrain boundaries. The results suggest that B substitutes for Co in the 1:5 phase and stabilizes a fine-scale cellular microstructure which consists of the 2:17 and 1:5 phases.

• Research Organization: Research and Development Laboratories-I, Nippon Steel Corporation, Nakahara-ku, Kawasaki 211, Japan
• OSTI ID: 6696206
• Journal Information: J. Appl. Phys.; (United States), Vol. 64:10
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON
METALLURGICAL EFFECTS
COBALT ALLOYS
MAGNETIC PROPERTIES
SINTERING
COPPER ALLOYS
IRON ALLOYS
PERMANENT MAGNETS
SAMARIUM ALLOYS
ZIRCONIUM ALLOYS
BORON ADDITIONS
COERCIVE FORCE
FABRICATION
MICROSTRUCTURE
PRECIPITATION HARDENING
ALLOYS
BORON ALLOYS
CRYSTAL STRUCTURE
ELEMENTS
HARDENING
MAGNETS
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
SEMIMETALS
360101* - Metals & Alloys- Preparation & Fabrication
360104 - Metals & Alloys- Physical Properties