Preparation of anisotropic hexagonal barium ferrite sintered magnet
US5811024A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 1996 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Jun 25, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/2683
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An anisotropic hexagonal barium ferrite sintered magnet is prepared by molding a powder barium ferrite raw material in a magnetic field into a compact and sintering the compact; or by molding a powder barium ferrite raw material in a magnetic field into a compact, disintegrating the compact into particles, compacting the particles in a magnetic field into a second compact, and sintering the second compact. In either case, the raw material contains calcined hexagonal barium ferrite, a silicon component, and a barium component. The resulting anisotropic hexagonal barium ferrite sintered magnet has improved sintered density and coercivity while the method minimizes deformation during sintering which is otherwise caused by the difference between the shrinkage factors in axis c and a directions, and simplifies or omits post-treatment like polishing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.