Abstract
We studied changes in average particle size and particle size distribution of nanometer-sized diamond particles caused by variations in ultrasound exposure time. The diamond particles had a primary particle size of about 5 nm, but aggregated to about 5 μm immediately after manufacture. Particles of this type were exposed to ultrasound at 150 kHz in water tank, and ultrasound exposure time was varied over a range of 20 s to 1200 s. Our results show that average particle size and particle size distribution of the diamond particles changed with increasing ultrasound exposure time. At exposure times of 300 s and 1200 s, the diamond particles had an average particle size less than about 100 nm. Furthermore, at 300 s and 1200 s, the diamond particles had a narrow particle size distribution in the nanometer range. In our future work, changes to the zeta potential of nanometer-sized diamond particles by increased ultrasound exposure time will be measured as well, because zeta potential affects the dispersion stability of diamond particles. The dispersion mechanism of the diamond particles by ultrasound exposure will also be considered.
