Magnetic inductive method

The magnetic induction method (ISO 2178) is an electromagnetic method for non-destructive testing of materials . It is used to measure the thickness of magnetically neutral layers on a magnetic base material.

principle

During the test, an alternating magnetic field is generated by a coil . In contrast to eddy current testing , significantly lower frequencies are used. Eddy current effects are rather undesirable here. The magnetic circuit, which consists of the sensor and the base material, changes its properties depending on the layer thickness. This effect is measured and converted into a layer thickness .

Since the measuring signal depends on the magnetic properties and the geometry of the base material, it must first be calibrated on an uncoated workpiece . Only in applications with standard geometries and materials can measurements be made without calibration.