Ferrite sintered magnet
US8980116B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 27, 2008 |
| Grant date | Mar 17, 2015 |
| Priority date | — |
| Expiry date | Feb 2, 2030 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2235/788
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A sintered ferrite magnet having a ferrite phase with a hexagonal structure as the main phase, wherein the composition of the metal elements composing the main phase is represented by the following general formula (1):RxCamA1−x−m(Fe12−yMy)z: (1),x, m, y and z in formula (1) satisfying all of the conditions represented by the following formulas (2)-(6):0.2≦x≦0.5: (2)0.13≦m≦0.41: (3)0.7x−m≦0.15: (4)0.18≦yz≦0.31: (5)9.6≦12z≦11.8: (6),and wherein the density of the sintered ferrite magnet is at least 5.05 g/cm3, and the crystal grains of the sintered ferrite magnet satisfy all of the conditions represented by the following formulas (7) and (8), where L μm is the average for the maximum value and S μm is the average for the minimum value among the diameters passing through the center of gravity of each grains in the crystal cross-section parallel to the c-axis direction of hexagonal structures.L≦0.95: (7)1.8≦L/S≦2.5: (8).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.