Can anybody confirm if 47nm Al2O3 dispersion be done with 30 min of sonication
in DI water?

My co-worker insist that 30 min of sonication be good enough for the dispersion
but as far as I know, 30 min of sonication couldn't be any close to the
dispersion.

Am I right?

Can anybody suggest for the better dispersion method for this? I want to
disperse without any surfactant. I want to disperse AL2O3 into pure DI water
with the dilution of 0.5%, 1% ...

Please suggest whatever method you know.

Thanks,