electromagnetic or magnetostriktiver transducer with a sintered oxydischen and ferromagnetic core whose material has a cubic crystal structure

摘要

958,680. Grinding. PHILIPS ELECTRICAL INDUSTRIES Ltd. Sept. 30, 1960 [Oct. 2, 1959], No. 33639/60. Drawings to Specification. Heading B3D. [Also in Divisions G5 and H4] The ferrite core of a magnetic head, particularly a record/playback head or a magnetostrictive supersonic generator used under water, is ground under the maximum feasible pressure and substantially without the use of lubricant by a tin grinding member whose surface is provided with diamond grains having a maximum size of about 2 microns, to produce a surface of low porosity on the transducing surface resistent to mechanical wear by a record or by water cavitation. The grinding surface may be the inside of a cylinder, having, e.g., an internal diameter of 20 cm. rotating at 2 r.p.m.