Method producing composite oxides for use as starting materials for producing ferrites
Patent 5190740 Issued on March 2, 1993. Estimated Expiration Date: 
December 7, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 7, 2010. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesHard ferrite powder and process for the preparation thereof Preparation of finely divided ferrite powders Process for producing ferrites High temperature process for producing fine magnetic particles of M-phase structure Patent #: 4765920 Inventors
AssigneeApplicationNo. 624054 filed on 12/07/1990US Classes:423/594.1, Iron (Fe) containing252/62.62, With Group II metal or lead252/62.64MagnesiumExaminersPrimary: Langel, Wayne A.Attorney, Agent or FirmForeign Patent References
International ClassC01G 049/02Foreign Application Priority Data1990-06-21 JPAbstractA method for producing an oxide useful as a starting material for making soft ferrites comprised mainly of iron, zinc and at least one metal selected from manganese, magnesium, nickel and copper is described. In the method, while chlorides of metals other than zinc are roasted for oxidation to produce a composite oxide, zinc oxide is added during the roasting. This method ensures addition of zinc oxide at high yield without use of zinc chloride having a high vapor pressure. The resultant oxide for ferrites has desired ratios of metal constituents and contains spinel ferrites which are intermediate products with zinc oxide being uniformly dispersed. The use of the starting oxide leads to omission of a calcination step and a powder mixing step in the production process of ferrites. Ferrites with good quality can be obtained by direct sintering.An alternative method using zinc chloride instead of zinc oxide is also described which can provide an equivalent oxide for making ferrites.Other References
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