| 摘要 |
PURPOSE:To prevent the generation of heat and the occurrence of a ringing phenomenon, and to make it possible to conduct a direct winding by a method wherein a low iron loss ferrite layer is formed on the center part of a core and a high resistance ferrite layer is formed on the surface part of the core. CONSTITUTION:The composition of the center layer of the title ferrite core is adjusted in the range of 52.5 to 54.5mol% Fe2O3, 31 to 38mol% MnO and 8 to 15mol% ZnO. In the case of Mn-Zn ferrite in the above-mentioned range of composition, the low iron loss of 1000mw/cm<2> or less can be secured, and the heat generated on the core can also be suppressed low. On the other hand, the composition of the surface layer is adjusted in the range of 20 to 40mol% MgO, 15 to 25mol% ZnO, 0 to 10mol% MnO and the remaining part consisting of Fe2O3. The Mn-Mg-Zn ferrite in the range of the above-mentioned composition gives the high resistance (10<5> to 10<8>OMEGA/cm), which is in the range where a direct winding can be performed, is given to the core, and also the relative permeability (1 to 10), which is sufficient to suppress a ringing phenomenon, is given to the core. As a result, a ferrite of low iron loss, high permeability and high resistance can be obtained, thus heat generation and a ringing phenomenon can be prevented, and direct winding to the core can be conducted. |
