Verfahren zur Herstellung eines ferromagnetischen Körpers und Verwendung desselben

862,135. Magnetic compositions. PHILIPS ELECTRICAL INDUSTRIES Ltd. Oct. 17, 1958 [Oct. 21, 1957], No. 33217/58. Class 38 (2). A ferromagnetic material having a structure similar to that of the compound BaFe 12 O 19 has the formula wherein D represents at least one of the tetravalent metal Ti, Ge, Zr, Hf, Sn, wherein Me represents at least one of the bivalent metals Mn, Ni, Zn, Mg and Cu, and wherein O # a # 1, O # b # 1, O # C # 0.4, 0 < d # 2.5, 0 # e < 1, O # f # 3. The material is made by sintering, once or several times, a finely divided mixture of the constituent metal oxides, oxide yielding compounds or reaction products cf two or more of these oxides e.g. BaFe 12 O 19 . Sintering may take place between 1000‹ and 1450‹ C. and sintering agents e.g. silicates and fluorides may be added. A body exhibiting a preferred direction may be provided by sintering in a magnetic field, and this effect is enhanced when one of the constituents of the mixture itself exhibits preferred orientation. As an example the manufacture of BaTi 0.6 Co 0.6 Fe 10.8 O 19 included the steps of grinding the constituents in alcohol for 8 hours, suspended in acetone and moulded under 1 ton/square inch a magnetic field of 1000 oersted, heated up to 500‹ C. in 16 hours from 500-1210‹ C. in 5 hours and sintered for 2 hours at 1210‹ C. in O 2 .