EP0399665A1
Expired / Lapsed
EP
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Method of manufacturing ferrite crystals and method of producing ferrite powders preferably used therefor
Assignee: NGK Insulators Ltd
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Filing: 1990-04-26
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Granted: —
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Expires: 2010-04-26
Abstract
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.
Inventors
- 👤 Minoru Imaeda
- 👤 Emi Asai
- 👤 Katsunori Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 06:53
CPC Classifications
H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/34; H01F1/342; H01F1/344; H01F1/346; C; C01; C01G; C01G49/00; C01G49/0018; C01G49/0036; C01G49/0054; C04; C04B; C04B35/00; C04B35/01; C04B35/26; C04B35/622; C04B35/64; C04B35/645; C04B35/6455; C01P; C01P2002/00; C01P2002/30; C01P2002/50; C01P2004/00; C01P2004/51; C01P2004/52; C01P2004/60; C01P2004/61; C01P2004/62; C01P2006/00; C01P2006/42; C01P2006/60
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
74 words
A method of manufacturing ferrite crystals with garnet structure by forming raw powders to obtain formed bodies and sintering the formed bodies, comprising the steps of, effecting a composition controlling for the raw powders to obtain composition controlled raw powders; forming the composition controlled raw powders to obtain formed bodies; sintering the formed bodies to obtain sintered bodies; and effecting a hot isostatic press treatment for the sintered bodies to obtain ferrite polycrystal bodies.
Claim 2
Independent Claim
74 words
A method of manufacturing ferrite crystals with garnet structure by forming raw powders to obtain formed bodies and sintering the formed bodies, comprising the steps of, effecting a composition controlling for the raw powders to obtain composition controlled raw powders; forming the composition controlled raw powders to obtain formed bodies; sintering the formed bodies to obtain sintered bodies; and effecting a hot isostatic press treatment for the sintered bodies to obtain ferrite polycrystal bodies.
Claim 3
Dependent Claim
22 words
A method according to claim 1, wherein said hot isostatic press treatment is effected under ambient gases including oxygen component above 0.1%.
Claim 4
Dependent Claim
39 words
A method according to claim 1, wherein said composition controlling is effected by preparing two kinds of ferrite powders with garnet structure, compositions of which are different from each other, and mixing the ferrite powders at a predetermined ratio.
Claim 5
Dependent Claim
25 words
A method according to claim 1, wherein said composition controlling is effected in the manner such that composition controlling errors are within 0.1% preferably 0.05%.
Claim 6
Dependent Claim
59 words
A method according to claim 1, wherein said raw powders are manufactured by preparing mixed solutions containing at least ferrous ion and yttrium ion or rare earth metal ion, coprecipitating hydroxides with the aid of base from the mixed solution, synthesizing the coprecipitated compounds by oxidizing ferrous ion into ferric ion, and separating, drying and calcining the coprecipitated compounds.
Claim 7
Dependent Claim
48 words
A method according to claim 1, wherein said raw powders are manufactured by preparing mixed solutions containing at least ferric nitrate and nitrate of yttrium or rare earth metal, dropping the mixed solution into a base solution to coprecipitate hydroxides, and separating, drying and calcining the coprecipitated compounds.
Claim 8
Dependent Claim
31 words
A method according to claim 1, further comprising the steps of connecting a mother ferrite single crystal to said ferrite polycrystal body; and growing single crystal into said ferrite polycrystal body.
Claim 9
Dependent Claim
50 words
A method according to claim 7, wherein with respect to said single crystal growing step is effected a heat-treatment at 800∼1600°C under oxygen atmosphere in a normal pressure, a normal HIP treatment under Ar atmosphere in 100∼2000 atm, and an oxygen HIP treatment under 0.1∼20% oxygen atmosphere in 100∼2000 atm.
Claim 10
Independent Claim
51 words
A method of producing ferrite powders comprising the steps of, preparing mixed solutions containing ferrous ion and the other metal ion; coprecipitating hydroxides with the aid of base from the mixed solutions; synthesizing the coprecipitated compounds by oxidizing ferrous ion into ferric ion; and separating, drying and calcining the coprecipitated compounds.
Claim 11
Independent Claim
51 words
A method of producing ferrite powders comprising the steps of, preparing mixed solutions containing ferrous ion and the other metal ion; coprecipitating hydroxides with the aid of base from the mixed solutions; synthesizing the coprecipitated compounds by oxidizing ferrous ion into ferric ion; and separating, drying and calcining the coprecipitated compounds.
Claim 12
Independent Claim
41 words
A method of producing ferrite powders comprising the steps of, preparing mixed solutions containing ferric nitrate and nitrates of the other metal; dropping the mixed solutions into a base solution to coprecipitate hydroxides; and separating, drying and calcining the coprecipitated compounds.
Claim 13
Independent Claim
41 words
A method of producing ferrite powders comprising the steps of, preparing mixed solutions containing ferric nitrate and nitrates of the other metal; dropping the mixed solutions into a base solution to coprecipitate hydroxides; and separating, drying and calcining the coprecipitated compounds.
References Cited (Backward Citations)
EP0105122A2
Cited
DE3529756A1
Cited
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