Additive Manufacturing of Magnetostrictive Cobalt Ferrite Thin Films for Structural Energy Harvesting

Magnetostrictive energy harvesters that convert ambient structural vibrations to useful electricity have the potential to supplement or replace batteries, especially in portable and wearable electronics. The magneto-mechanical coupling of magnetostricive materials converts mechanical energy to magnetic energy, and electro-magnetic coupling of electrical circuits converts magnetic energy to electrical energy. Additive manufacturing of magnetostrictive thin films is essential for building small-scale and flexible energy harvesters, which are difficult or even impossible to manufacture using traditional processes. To develop this technique, cobalt ferrite nanopowder was used to synthesize aqueous and non-aqueous inks for inkjet printing. Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) were used to analyze particle and agglomeration sizes. The viscosity of the inks was measured using a rotational rheometer. The ink properties, including specific particle size and viscosity, were fine-tuned to ensure successful printing. Different heat treatments and sintering processes for the printed thin films will be explored to determine their effects on the magnetostrictive properties.