Verfahren zur Herstellung eines keramischen,polykristallinen,magnetisch anisotropen Spinellferritkoerpers und nach diesem Verfahren hergestellter Spinellferritkoerper

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. AIIand BII are each one or more of FeII NiII MnII, CoII Zn, Mg, CuII and LiI + FeIII/2; and x is 6 or 8. At least part of the AIIO may be replaced by one or more compounds convertible to AIIO on heating, and part of the FeIII in the ferrite may be replaced by at least one of Al, CrIII and AII + MIV/2 where MIV is TiIV and/or SnIV. 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.