METHOD FOR MEASURING COERCIVE FORCE

摘要

PROBLEM TO BE SOLVED: To provide a nondestructive method of measuring coercive force capable of extracting only the coercive force information of a ferromagnetic material to be measured and thus performing a precise measurement. SOLUTION: A triangular wave signal transmitted from a triangular wave generator 4 is amplified by a power amplifier 5 and applied to the exciting coil of a magnetizer 2 as exciting current. The signal detected by a magnetic detector 3 is amplified by a signal amplifier 5 and then passed through a filter 7 to extract only a Barkhausen noise. A magnetic field detector 9 for measuring the surface directional magnetic field of a material to be measured 1 is provided on the vicinity of the surface of the material 1, the signal thereof is amplified by a magnetic field signal amplifier 10 to measure the magnetic field applied to the material 1. An arithmetic processing unit 8 calculates the intensity of the magnetic field required for the generation of the Barkhausen noise from the signal of the Barkhausen noise extracted by the filter 7 and the output signal of the magnetic field signal amplifier 10 and converts it into coercive force.