Radiation-induced changes in magnetic properties of Nd-Fe-B permanent magnets

Conference · Thu Jan 01 00:00:00 EST 1987

DOI:https://doi.org/10.1063/1.340734· OSTI ID:6128960

Brown, R D; Cost, J R

The high remanence and intrinsic coercivity of Nd-Fe-B magnets make them desirable for use in the accelerators. Use in the radiation environment of an accelerator requires that the sensitivity of these magnets to radiation be determined and the mechanisms responsible be understood. We present results comparing the relative radiation sensitivity of a number of commercially available Nd-Fe-B magnets. Small samples of these magnets were irradiated at the Omega West Reactor in a neutron flux of 2 x 10/sup 13/ n/cm/sup 2/s at a temperature of 350/sup 0/K (77/sup 0/C). At various time intervals during the irradiation, samples were removed from the reactor and the open-circuit remanence measured. We also measured the second quadrant demagnetization curve of samples before and after neutron irradiation to monitor changes in remanence and intrinsic coercivity. Our results show that the sensitivity to radiation varies widely among magnets from different vendors. In general, these samples showed a decrease in the remanence and an increase in the intrinsic coercivity. We present results showing that the rate of remanence decay decreases monotonically with increasing length-to-diameter (L/D) ratio for samples of the same material. Thus, it is important to compare decay rates corrected to some constant L/D ratio. 7 refs., 3 figs., 2 tabs.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 6128960
• Report Number(s): LA-UR-87-3043; CONF-871126-3; ON: DE88000528
• Resource Relation: Journal Volume: 63; Journal Issue: 8; Conference: 32. annual conference on magnetism and magnetic materials, Chicago, IL, USA, 9 Nov 1987; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
36 MATERIALS SCIENCE
ACCELERATORS
PERMANENT MAGNETS
PHYSICAL RADIATION EFFECTS
BORON ALLOYS
DEMAGNETIZATION
EXPERIMENTAL DATA
IRON ALLOYS
IRRADIATION
MAGNETIC PROPERTIES
NEODYMIUM ALLOYS
ALLOYS
DATA
INFORMATION
MAGNETS
NUMERICAL DATA
PHYSICAL PROPERTIES
RADIATION EFFECTS
RARE EARTH ALLOYS
430303* - Particle Accelerators- Experimental Facilities & Equipment
360104 - Metals & Alloys- Physical Properties
360106 - Metals & Alloys- Radiation Effects