Method for manufacturing a wound magnetic core

A method for manufacturing a wound magnetic core, comprising:

• a first operation in which a nonmagnetic insulating metal oxide powder is made to adhere to a surface of a soft magnetic metal ribbon having an amorphous structure;
• a second operation in which, following the first operation, the soft magnetic metal ribbon is wound in annular fashion to obtain a wound body at which the metal oxide powder intervenes between layers of the ribbon;
• a third operation in which the wound body is made to undergo heat treatment in a nonoxidizing atmosphere;
• a fourth operation in which, following the third operation, the wound body is subjected to treatment for formation of an oxide film in an oxidizing atmosphere at a temperature lower than a heat treatment temperature at the third operation to cause oxidation of the surface of the soft magnetic metal ribbon;
• a fifth operation in which, following the fourth operation, spaces between the layers of the ribbon of the wound body are impregnated with resin and curing thereof is carried out;
• wherein:
• an amount of the metal oxide powder which is made to adhere thereto at the first operation is not less than 0.1% but not greater than 1.2% when expressed as a metal oxide powder wt % ratio as obtained using the following formula (1);
• and
• metal oxide wt % ratio (%)=(weight of metal oxide adhering to soft magnetic metal ribbon/weight of soft magnetic metal ribbon)×100 (1).