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Due to high piezomagnetic coefficient of the synthetic giant magnetostrictive materials, they are able to provide good enough force and displacements for industrial applications. Some natural materials such as nickel also exhibit magnetostrictive properties, but with poor performance, which might be improved by some electromagnetic manipulations. In this study, the effect of different coil parameters such as current, frequency, the number of coil turn, and the core lamination factor in different directions ([X or Y] and Z axes), on the performance of a nickel-core magnetostrictive transducer is investigated. Since the fluctuation of magnetostrictive force in the longitudinal direction of core (along the Z-axis) is an important parameter for generating the ultrasonic waves, the results showed that this force fluctuation decreases with increasing frequency. By increasing the lamination factor in the X direction, the fluctuation of magnetostrictive force along the Z-axis remains constant. However, the ultrasonic performance of the magnetostrictive transducer may be optimized by proper selection of lamination factor along the X-axis. The relationships between the results were investigated in more detail and presented as linear equations. Based on these equations, it was concluded that current and turn number of coil has the greatest positive impact on the magnetostrictive performance of the transducer, while increasing the frequency and lamination factor have a weakening effect.

In recent years, ultrasonic machining has been developing rapidly and it is used in areas such as abrasive machining, cleaning, and welding. In this research, a magnetostrictive device with pure nickel conical core with cone angle of 30 degrees was constructed. The observed sound pressure level was used as a measure of transducer performance. Also the ability of the device to reduce the residual pesticide on cucumber surface due to cavitation was evaluated. The results showed that the sound pressure from simulation by JMAG-Designer software is almost the same as the sound pressure produced in the constructed transducer. To assess the performance of the device in removing residual pesticide from cucumber surface and evaluate the changes in peel texture of cucumber, the GC and SEM methods were used, respectively. The GC results showed that with 20 min treatment, the removal of pesticide based on height and chromatogram area were 75% and 83%, respectively. The SEM results showed that by increasing the treatment time, the stomatal pore area reduced from 144.74 (reference) to 30.56(20 min treatment). This results are promising, hence further research is suggested towards enhancing the device for commercial use in biomaterials processing operations such as cleaning and removing pesticides from fruits and vegetables.

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