The magnetic field strength in a nickel rod with an applied uniform external field is studied by transmitting ultrasonic waves. In nondestructive testing (NDT), longitudinal plane waves are transmitted from an ultrasonic transducer to the object, which is characterized by alternating regions of compression and dilation, If the objects are ferromagnetic materials, the compression waves generate the magnetoelastic energy in magnetic substances, which are equivalent to the magnetic anisotropy field. This field passes through magnetic substances with the velocity of ultrasound and is observed as the electromotive force (emf) induced in the sensing coil. As the ultrasonic waves are transmitted continuously to a rod specimen, the ultrasonic stationary wave is formed in it and the high-frequency magnetic field is generated in nodes of the stationary state by the inverse effect of magnetostriction, then the emf is induced in the nodes. In this paper the strength of the effective magnetic field in the nickel rod is estimated by measuring the electromotive force induced by ultrasonic waves passing through magnetic materials. (C) 2002 Wiley Periodicals, Inc.
