Abstract The manufacture of a ceramic, polycrystalline, magnetically anisotropic spinel ferrite bodies by sintering a mixture containing crystals of a compound PbMe''IIFe16IIIO27 and/or of the compound PbFe12III019, the magnetic preferential axes or magnetic preferential planes of said crystals in said mixture being, to a certain extent, oriented mutually parallel, in which the abovementioned spinel ferrite bodies are formed as the product of a topotactical reaction which mainly occurs according to the equation PbMe2''IIFe16IIIO27+6MeIIO 6MeIIFe2IIIO4+2Me''IIFe2III04+PbO and/or according to the equation PbFe12III019+6MeII0 6MeIIFe2III04+Pb0. WHEREIN MeII and Me''II both represent at least one (possibly all the same) representative of the group formed by the bivalent elements FeII, NiII, MnII, CoII, Zn, Mg, CuII and the bivalent combination (LiI+FeIII)/2 and wherein FeIII may be partly replaced by A1 and/or CrIII and/or at least one of the trivalent combinations (MeII+TiIV(/2 and (MeII+SnIV
A method as claimed in claim 1, wherein the mixture is compacted in a magnetic directional field.
Claim 2
Dependent Claim
40 words
A method as claimed in claim 1, wherein the mixture is admixed with a binder and rolled or extruded into plates, sheets, leaves, or strips, after which the binder is burned and the plates, sheets, leaves, or strips are sintered.
Claim 3
Dependent Claim
29 words
A method as claimed in claim 1 wherein the crystallized ferrite compound having axial or planar magnetic crystal anisotropy has a chemical composition according to the formula PbO. (Fe2IIIO3)8(Me''IIO)2.
Claim 4
Dependent Claim
70 words
A method as claimed in 1 wherein the FeIII in the crystallized ferrite compound having axial or planar magnetic crystal anisotropy is partially replaced by at least one member of the group consisting of the trivalent elements Al and CrIII and the trivalent combinations (MeII+MeIV)/2, wherein MeII is defined in claim 1 and MeIV is at least one of the elements selected from the group consisting of TiIV and SnIV.
Claim 5
Dependent Claim
16 words
A method as claimed in claim 4 in which the crystallized ferrite compound is Pb Fe12O19.
Claim 6
Dependent Claim
15 words
A method as claimed in claim 4 in which the crystallized ferrite compound is PbCo2Fe16O27.
Claim 7
Dependent Claim
15 words
A method as claimed in claim 4 in which the crystallized ferrite compound is PbNi2Fe16O27.
Claim 8
Dependent Claim
15 words
A method as claimed in claim 4 in which the crystallized ferrite compound is PbZn2Fe16O27.