Method for the contactless determination of a thickness of a layer made of electrically-conductive material

A method for the contactless determination of a thickness of a layer (20) made of electrically-conductive material applied to a component (17) made of ferromagnetic material, the following measuring steps taking place with the aid of at least one measuring coil (14) carrying an alternating current and mounted on a coil form (13), the change in inductance of which is evaluated:

• Determine the inductance value L0,d,f1 of the coil (14) determined in a measurement carried out exclusively with respect to a component (17) as the object of measurement made of ferromagnetic material, the coil (14) being acted upon with a first alternating current frequency f1;
• the distance between the coil form (13) and the object of measurement is d
• Determine the inductance value L0,d,f2 of the coil (14) in a measurement carried out exclusively with respect to a component (17) as the object of measurement made of ferromagnetic material, the coil (14) being acted upon with a second alternating current frequency f2;
• the distance between the coil form (13) and the object of measurement is d
• Convert the determined inductance value L0,d,f2 to a dimensionless characteristic value K
• Convert the characteristic value K with the aid of a distance characteristic into the value of distance d
• Determine the inductance value Lx,d,f1 of the coil (14) in a measurement carried out with respect to the layer (20) to be determined, the coil (14) being acted upon with the first alternating current frequency f1;
• the distance between the coil form (13) and the coated component (17) is d
• Convert the determined inductance values L0,d,f1 and Lx,d,f1 to a dimensionless measured value Me
• Convert the measured value Me with the aid of a family of calibration curves with consideration for the determined value of distance d to a layer thickness value a.