Thermal stability of five sintered rare-earth--cobalt magnet types

Journal Article · Fri Apr 15 04:00:00 EDT 1988 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.340571· OSTI ID:5419404

Li, D; Mildrum, H F; Strnat, K J

Five commercially available magnet types: SmCo/sub 5/, high- and low-coercivity Sm/sub 2/(Co,Fe,Cu,Zr)/sub 17/, (Sm,Ce)(Co,Cu,Mn)/sub 7/, and Ce(Co,Cu,Fe)/sub 5/: were systematically studied to obtain a comprehensive overview of the following magnetic properties of interest to the user: reversible and irreversible losses during thermal cycling between 20 /sup 0/C and 250 /sup 0/C; open-circuit remanent flux loss during aging at 150 /sup 0/C and 250 /sup 0/C up to 2100 h, at permeances of p = -2.5 and -0.5. Room-temperature demagnetization curves before and after aging are compared to distinguish recoverable (magnetic) from irrecoverable (structural) aging effects. The Sm/sub 0.5/Ce/sub 0.5/(Co,Cu,Mn)/sub 7/ magnets had the best long-term stability under all test conditions, followed by the high-H/sub c/ 2-17 and SmCo/sub 5/. The low-H/sub c/ 2-17 exhibited the greatest absolute flux loss under all conditions, but it stabilized fairly well after 10 h, and the loss was recoverable by remagnetizing. In contrast, for Ce(Co,Cu,Fe)/sub 5/ the losses continued up to 2100 h without a sign of flux stabilization.

• Research Organization: Central Iron and Steel Research Institute, Beijing, People's Republic of China
• OSTI ID: 5419404
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 63:8; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ALLOYS
COBALT ALLOYS
DEMAGNETIZATION
HYSTERESIS
MAGNETIC FLUX
MAGNETISM
MAGNETIZATION
MAGNETS
MATERIALS
PERMANENT MAGNETS
RARE EARTH ALLOYS
SAMARIUM ALLOYS
SINTERED MATERIALS
THERMOMAGNETISM