Ultrasound Ablation of a Solid Sample in Water Accompanied by Formation of Nanoparticles

For the first time, nanoparticles are observed that result from ablation of a bulk solid-state sample in water as its surface is affected by high-intensity focused ultrasound pulses with a carrier frequency of 1.8 MHz and peak-to-peak acoustic pressure of 50 MPa in the focus. As photo and video recordings show, formation of ablation particles and their ejection into water under these extreme conditions is of local and spallation-explosive character. Size and mass distributions of the ablation particles measured using a laser particle analyzer reveal that ultrasound ablation results in formation of nanometer-sized particles among others. The size of these particles mostly ranges between 20 and 60 nm with the distribution maximum at 35 nm.