Process for making fine magnetic ferrite powder and dense ferrite blocks
US4440713A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 30, 1982 |
| Grant date | Apr 3, 1984 |
| Priority date | — |
| Expiry date | Sep 30, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2002/32
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A manufacturing process for making a finer ferrite powder which can then be used to make a very dense block of the ferrite ceramic. The process for making the powder includes the steps of co-precipitation of an aqueous solution of metal ions and an ammonium oxalate solution. The co-precipitation particles are separated, washed and dried. The particles are low-temperature calcined and then vibro-energy or ball milled and dried. The particles are fluffed and broken up in a blender and pressed into a mold for sintering and pressing in a hot isostatic press procedure. The ferrite blocks are then post annealed in an oxygen atmosphere and cooled to form a dense magnetic ceramic particle. Preferably the process is for use in the production of nickel-zinc ferrite used for magnetic heads.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.