Magnetic Properties of Heat-Treated Fe-Co Alloys and Their Potential for Vibration Energy Harvesting

We studied the effects of alloy composition and heat-treatment conditions of the Fe-Co magnetostrictive alloys on the output voltage of a cantilever-type vibration energy harvester with the alloys. Fe-Co binary alloys that were annealed and subsequently water-quenched produced higher output voltages than those produced by alloys that were cold-rolled or annealed but not quenched. Annealed and quenched Fe-Co alloys possessed higher saturation magnetization, permeability, and magnetostriction susceptibility but lower residual magnetization, coercive force, and magnetostriction. Thus, we found that it was necessary to control not only the alloy composition and magnetostriction but also other magnetic parameters in order to increase the output voltage of power generator using magnetostrictive materials.