Iron rusts on its own, slowly, over months or years. Now, researchers at Tohoku University have found a way to compress the process of metal reacting with water to form oxide, taking mere hours and using nothing more than ultrasound. Details were published in the journal Ultrasonics Sonochemistry.

Spinel-type iron oxide nanoparticles are widely used in magnetic materials, adsorbents, catalysts, magnetic separation and biomedical research. Conventional synthesis methods typically start with soluble iron salts, which are then converted into particles using chemicals such as ammonia or sodium hydroxide.

The Tohoku University team took a different approach, generating the nanoparticles directly from iron powder and water activated by ultrasound.