Abstract: An eddy current probe comprising two solenoid coils wound around a common rectangular wafer base of high permeability material extending beyond the coils at wafer corners with the wafer becoming the solenoid core. Posts also of high permeability material depend from a wafer front at its corners with coils crossing orthogonally on the wafer. The coils are connected to alternating current to produce magnetic fields that have like magnetic poles at wafer corners diagonally opposed across the wafer, the coils switching in phase to alternate the magnetic field between posts at base diagonal corners. With the posts at the wafer base corners, the combined magnetic fields generated from the orthogonal coils conduct through the posts and emanate from post ends. The post ends have a curvature matching that of a material to be tested for better coupling the magnetic field into the material.

Abstract: An eddy current probe comprising two solenoid coils wound around a common rectangular wafer base of high permeability material extending beyond the coils at wafer corners with the wafer becoming the solenoid core. Posts also of high permeability material depend from a wafer front at its corners with coils crossing orthogonally on the wafer. The coils are connected to alternating current to produce magnetic fields that have like magnetic poles at wafer corners diagonally opposed across the wafer, the coils switching in phase to alternate the magnetic field between posts at base diagonal corners. With the posts at the wafer base corners, the combined magnetic fields generated from the orthogonal coils conduct through the posts and emanate from post ends. The post ends have a curvature matching that of a material to be tested for better coupling the magnetic field into the material.

Abstract: The directed field array comprises a cylindrical solenoid 10 and a base 20 located transverse the solenoid axis 11. An array of mutually spaced apart posts 24 extends from the base 20 such that the magnetic field 22 passes through the base 20 and into the array of posts 24, dividing and focusing the magnetic field into discretized magnetic field divisions 22′ through the several posts. In a first configuration, the base 20 is disposed transverse the end of the coil center or core 12 with the array of posts 24 extending from the base 20 away from the solenoid 10 longitudinally with the solenoid axis 11. In an alternative configuration, at least one base 20″ locates at a solenoid end 30 transverse the solenoid axis 11 with an array of posts 24″ extending radially from the base 20, equally spaced apart circumferentially about the base. Multiple bases are typically aligned with their posts staggered.

Abstract: The directed field array comprises a cylindrical solenoid 10 and a base 20 located transverse the solenoid axis 11. An array of mutually spaced apart posts 24 extends from the base 20 such that the magnetic field 22 passes through the base 20 and into the array of posts 24, dividing and focusing the magnetic field into discretized magnetic field divisions 22′ through the several posts. In a first configuration, the base 20 is disposed transverse the end of the coil center or core 12 with the array of posts 24 extending from the base 20 away from the solenoid 10 longitudinally with the solenoid axis 11. In an alternative configuration, at least one base 20″ locates at a solenoid end 30 transverse the solenoid axis 11 with an array of posts 24″ extending radially from the base 20, equally spaced apart circumferentially about the base. Multiple bases are typically aligned with their posts staggered.