Encapsulated oxidation-resistant iron-neodymium-boron permanent magnet
US5272008A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1992 |
| Grant date | Dec 21, 1993 |
| Priority date | — |
| Expiry date | Mar 16, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31855
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Oxidation-resistant, individually encapsulated neodymium-iron-boron permanent magnet particles are provided. The particles are individually coated with, preferably, three distinct organic layers and are useful for the subsequent formation of a molded permanent magnet article. The first coating is an antioxidant layer employed for the retardation of oxidation of the coated particle. The second intermediate layer consists of an appropriate thermosetting epoxy to provide the adhesion required during subsequent molding of the particles. The third and outermost layer consists of polystyrene and is employed to keep the particles free flowing, since the epoxy layer may be tacky after deposition, thereby hindering the free flowability of the particles. The coatings are applied sequentially using fluidized bed coating techniques. The encapsulated particles can then be molded and appropriately cured. In addition, the encapsulated particles exhibit enhanced oxidation resistance, including at elevated temperatures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.