Mn-zn ferrite magnetic core and its production

PURPOSE: To enlarge the voltage resistance and insulation resistance between a core and a magnetic substance by forming a high-resistance layer on the surface of an Mn-Zn ferrite magnetic substance, satisfying specified measure condition. CONSTITUTION: High-resistance layers (oxide films) 7 are made on the surfaces of Mn-Zn ferrite magnetic substances 6S and 6R, and these are constituted satisfying the following measure condition. Defining that the size of a sample for measurement (measure condition) is 10×10×mm 3 , and that the resistance between the obverse and the reverse at the time of having shaved this sample of measurement by d (μm) from the surface is Rd, R200<10KΩ, and besides R50≥10×R200, and besides R0≥102×R200. Therefore, for example, in case of having made a rotary core of this Mn-Zn ferrite magnetic core, it follows that a high-resistance layer 7 exists between coils (2s and 4s) and (2r and 4r), in which signal currents flow, and magnetic substances 6S and 6R. Hereby, the voltage resistance and the insulation resistance between the coils (2s and 4s) and (2r and 4r) and the magnetic substances 6S and 6R can be enlarged. COPYRIGHT: (C)1993,JPO&Japio