Magnetostrictive materials and method for improving AC characteristics in same
US6273965A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1997 |
| Grant date | Aug 14, 2001 |
| Priority date | — |
| Expiry date | Oct 17, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10N35/85
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention provides Terfenol-D alloys ("doped" Terfenol) having optimized performances under the condition of time-dependent magnetic fields. In one embodiment, performance is optimized by lowering the conductivity of Terfenol, thereby improving the frequency response. This can be achieved through addition of Group III or IV elements, such as Si and Al. Addition of these types of elements provides scattering sites for conduction electrons, thereby increasing resistivity by 125% which leads to an average increase in penetration depth of 80% at 1 kHz and an increase in energy conversion efficiency of 55%. The permeability of doped Terfenol remains constant over a wider frequency range as compared with undoped Terfenol. These results demonstrate that adding impurities, such as Si and Al, are effective in improving the ac characteristics of Terfenol. A magnetoelastic Gruneisen parameter, .gamma..sub.me, has also been derived from the thermodynamic equations of state, and provides another means by which to characterize the coupling efficiency in magnetostrictive materials on a more fundamental basis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.