METHOD OF MANUFACTURING A CERAMIC, POLYCRYSTALLINE, MAGNETICALLY ANISOTROPIC SPINEL FERRITE BODY AND SPINEL FERRITE BODY MANUFACTURED BY THIS METHOD

摘要

1,225,228. Ferrites. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 4 Sept., 1969 [7 Sept., 1968], No. 43839/69. Heading C1A. [Also in Division H1] ] A polycrystalline magnetically anisotropic spinel ferrite body is made by mixing a crystallized ferrite having axial or planar crystal anisotropy and defined by the formula with an oxide A"O, shaping the mixture while magnetically orientating the individual crystals by magnetic and/or mechanical .means, And then sintering the shaped body. ASPII/SPand BSPII/SP are each one or more of FeSPII/SP NiSPII/SP MnSPII/SP, CoSPII/SP Zn, Mg, CuSPII/SP and LiSPI/SP + FeSPIII/SP/2; and x is 6 or 8. At least part of the ASPII/SPO may be replaced by one or more compounds convertible to ASPII/SPO on heating, and part of the FeSPIII/SP in the ferrite may be replaced by at least one of Al, CrSPIII/SP and ASPII/SP + MSPIV/SP/2 where MSPIV/SP is TiSPIV/SP and/or SnSPIV/SP. Magnetic orientation may be effected by application of a magnetic field or by incorporating a binder, rolling or extruding into strips or plates, and then burning of the binder before sintering. An example describes the preparation of nickel ferrites (NiFe 2 O 4 ) from PbFe 12 O 19 and NiO.