Device and method for the material testing and/or thickness measurements of a test object that contains at least fractions of electrically conductive and ferromagnetic material

A device for the material testing of a test object comprising at least fractions of electrically conductive and ferromagnetic material and at least one engineered surface with at least one electromagnetic ultrasonic transducer assembly that comprises a permanent or electromagnetic assembly with at least two magnetic poles of different magnetic polarity that face the engineered surface, and at least one eddy current coil that projects onto the engineered surface between the two magnetic poles in relation to the engineered surface, and wherein

• the permanent or electromagnetic assembly includes a U-shaped magnet body, the magnetic poles of which flatly adjoin the engineered surface, wherein the magnet body extends in a bridge-like fashion over a region of the engineered surface in which the at least one eddy current coil projects or on a surface of which that faces the test object on which the at least one eddy current coil is arranged;
• the permanent or electromagnetic assembly at least induces a tangential magnetic field that is oriented parallel to the engineered surface in the test object;
• the at least one eddy current coil has a coil geometry that forms a spatially defined region within the test object in which a resultant circuital vector field with a higher eddy current density than the surrounding regions and a uniform eddy current direction is created;
• and
• the eddy current direction of the circuital vector field induced in the test object is oriented perpendicular to the magnetic field lines of the tangential magnetic field in the region of the higher eddy current density.