Non-destructive eddy current diagnostics of the structure, composition, physical and mechanical properties of ferromagnetic materials, as well as eddy current monitoring of the operational parameters of products manufactured from them, requires knowledge of the magnetic characteristics of these materials. In eddy current measurements, the results obtained are influenced by a significant number of factors — magnetic and electrical properties of materials, geometric characteristics of products, measurement conditions, design features of an eddy current sensor, etc. Also, the magnetic properties themselves have high structural sensitivity. Thus, identification of the diagnosed parameters puts great importance on the tasks to separate the influencing factors and isolate the contribution of the magnetic properties.
This paper describes the measuring and computing system that allows automatic determination of the magnetic permeability of soft magnetic ferromagnetic materials at various values of the strength of the external magnetizing field. The system has been tested using soft magnetic ferrites samples. An experimental dependence of the magnetic permeability on the magnitude of the magnetic field for the initial section of the main magnetization curve is presented. The obtained initial magnetic permeability is compared with the data of independent indirect measurements.
The proposed system provides an increase in the reliability and accuracy of the results of the experimental determination of magnetic characteristics and can be used for non-destructive diagnostics of products made of soft magnetic ferromagnetic materials.
A measurement setup for acquiring the local magnetic properties of plastically deformed soft magnetic materials
