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M-h characteristics and demagnetization resistance of samarium-cobalt permanent magnets to 300 c
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Niedra, Janis M. |
| Copyright Year | 1992 |
| Description | The influence of temperature on the M-H demagnetization characteristics of permanent magnets is important information for the full utilization of the capabilities of samarium-cobalt magnets at high temperatures in demagnetization-resistant permanent magnet devices. In high temperature space power converters, such as free-piston Stirling engine driven linear alternators, magnet demagnetization can occur as a long-term consequence of thermal agitation of domains and of metallurgical change, and also as an immediate consequence of too large an applied field. Investigated here is the short-term demagnetization resistance to applied fields derived from basic M-H data. This quasistatic demagnetization data was obtained for commercial, high-intrinsic-coercivity, Sm2Co17-type magnets from 5 sources, in the temperature range 23 to 300 C. An electromagnet driven, electronic hysteresigraph was used to test the 1-cm cubic samples. The observed variation of the 2nd quadrant M-H characteristics was a typical rapid loss of M-coercivity and a relatively lesser loss of remanence with increasing temperature. The 2nd quadrant M-H curve knee point is used to define the limits of operation safe against irreversible demagnetization due to an excessive bucking field for a given flux density swing at temperature. Such safe operating area plots are shown to differentiate the high temperature capabilities of the samples from different sources. For most of the samples, their 2nd quadrant M-H loop squareness increased with temperature, reaching a peak or a plateau above 250 C. |
| File Size | 547649 |
| Page Count | 10 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19920019480 |
| Archival Resource Key | ark:/13960/t1bk68w3q |
| Language | English |
| Publisher Date | 1992-08-01 |
| Access Restriction | Open |
| Subject Keyword | Electronics And Electrical Engineering Permanent Magnets High Temperature Piston Engines Thermal Energy Power Converters Domains Quadrants Losses Flux Density Temperature Effects Electromagnets Stirling Engines Demagnetization Linear Alternators Remanence Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
