Method of manufacturing ferrite crystals
AssigneeNGK Insulators, Ltd.
InventorsMinoru Imaeda, Emi Asai, Katsunori Okamoto
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Abstract
A method of manufacturing ferrite crystals such as single crystal bodies and polycrystal bodies with garnet structure is disclosed, which includes the steps of effecting a composition controlling for raw powders, forming raw powders, sintering formed bodies and effecting hot isostatic press treatment for sintered bodies. Also, a method of producing ferrite powders preferably used for the ferrite crystal manufacturing method mentioned above. The thus obtained ferrite crystal bodies with garnet structure show good magnetooptical properties such as light transmissivity, Faraday rotation angle and Verdet constant, and are preferably used for magnetooptical elements such as optical isolators and optical magnetic field sensors etc.
Claims7
A method of manufacturing ferrite crystals with garnet structure, comprising the steps of:
- preparing first and second ferrite powders each having garnet structure, said powders having components, the molar percentages of which are higher and lower, respectively, than a target composition;
- mixing said first and second ferrite powders at a predetermined ratio to obtain a composition controlled ferrite powder such that the components of the composition controlled ferrite powder have molar percentages which are within 0.1 mol % of the target composition;
- forming said composition controlled ferrite powder to obtain a formed body;
- sintering said formed body to obtain a sintered body;
- and
- subjecting said sintered body to a hot isostatic pressing treatment to obtain a ferrite polycrystal body.
A method of manufacturing ferrite crystals with garnet structure, comprising the steps of:
- preparing first and second ferrite powders each having garnet structure, said powders having components, the molar percentages of which are higher and lower, respectively, than a target composition;
- mixing said first and second ferrite powders at a predetermined ratio to obtain a composition controlled ferrite powder such that the components of the composition controlled ferrite powder have molar percentages which are within 0.05 mol % of the target composition;
- forming said composition controlled ferrite powder to obtain a formed body;
- sintering said formed body to obtain a sintered body;
- and
- subjecting said sintered body to a hot isostatic pressing treatment to obtain a ferrite polycrystal body.
Dependencies are inferred from the claim text.