Magnetostrictive vibrator utilizing iron–cobalt alloy

In this paper, a novel magnetostrictive vibrator with a unique and integrated design is proposed and developed by using a kind of iron–cobalt alloy (Permendur). Permendur is a giant magnetostrictive material (GMM) with magnetostriction exceeding 70 ppm, Young's modulus of 210 GPa, high relative permeability and sufficient force for actuation, which shows a good performance as actuator material and has been drawn a lot of attention. The magnetostrictive vibrator has four legs around which the coils are wound. The legs can be pushed (expansion) and pulled (contraction) independently through controlling the input currents of the coils. The actuation principle of the magnetostrictive vibrator is illustrated. The lateral vibrating motion can be generated by using a pair of opposing coils, whereas 2D vibrating motion can be obtained by using two pairs of opposing coils. The finite element analysis (FEA) is adopted to analyze the vibration mode and assist the concrete design of magnetostrictive vibrator. Through some fundamental experiments, the characteristics of the magnetostrictive vibrator are evaluated. For the application, it has been successfully used as a vibrating polisher in the ultra-precision finishing of micro-optic molds.