Method for demagnetizing and measuring remanence and coercivity characteristics of a magnetic sample
US6201386A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1998 |
| Grant date | Mar 13, 2001 |
| Priority date | — |
| Expiry date | Apr 23, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for determining remanence and coercivity of high strength rare earth magnets, without full determination of their hysteresis characteristics and subsequent computation, enables high speed, high throughput testing of such magnets in a production facility. The magnets are first fully magnetized by capacitor discharge through a pulsing magnetizing coil, if not already fully magnetized, and their remanence can be noted at zero applied field. Then the magnets are progressively demagnetized, again by capacitor discharge through a pulsing coil, and, with the state of magnetization of the magnets and the strength of demagnetizing field continuously monitored, note is taken of the strength of the demagnetizing field when the magnetization of the magnet is reduced to zero. Based on this sole measurement, the coercivity of the magnet is derived. The apparatus employs a Hall effect probe with a Teslameter or coil system with a fluxmeter to monitor the state of magnetization of the test magnets and employs a peak-reading current meter to monitor the strength of the demagnetizing field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.