Ferromagnetic ceramic material having high maximum permeability and high flux density

摘要

739,134. Magnetic compositions. STEATITE RESEARCH CORPORATION. Oct. 15, 1953 [Nov. 24, 1952], No. 28447/53. Addition to 703,676. Class 38 (2). A ferromagnetic body of high permeability having a Curie point above 120‹ C comprises magnesium zinc ferrite which contains 1.5-8 per cent by weight copper oxide and 2.0-8 per cent by weight nickel oxide, with optionally some lithium oxide. The preferred mol. percentages are MgO, 8-25; ZnO, 14-25; CuO, 2-11; NiO,3-12; Li 2 O, 0-3 ; Fe 2 O 3 , 47.4-52.4. All the oxides may be ground together, or the Mg may be calcined with parts of the ZnO and Fe 2 O 3 which calcine is added to the remaining ingredients. The nickel oxide may be introduced as nickel ferrite, which may be scrap of the copper as basic copper carbonate. The ingredients may be ground with water, dried, prefired at 1050‹ C., reground, mixed with water and an organic binder and fired at 1300-1320‹ C.