Method of making laminated magnetic material

Abstract

An extrusion billet is fabricated from layers of soft magnetic material separated by one or more metal layers. The billet is coreduced and heat treated to impart the desired magnetic properties to the soft magnetic material and also to form intermetallic insulating layers between the magnetic layers. Electric field shield sections are formed in a similar manner by placing relatively thick layers of copper between adjacent layers of metal located adjacent to the layers of soft magnetic material. The layers of soft magnetic metal can also be separated by a layer of semiconductor material; or a metal foil having a semiconductor-forming or high electrical resistivity forming material deposited thereon. In the latter case no extrusion is required. Instead, pressure and heat cause the materials to react and form either a semiconductor layer or a layer with an electrical resistivity higher than about 10.sup..sup.-4 ohm-cm between adjacent layers of soft magnetic metal. Even the deposition step is eliminated by separating and bonding the layers of soft magnetic metal with glass so long as the glass and soft magnetic metal have similar coefficients of thermal expansion.

Dependencies are inferred from the claim text.