On the nature of the mechanically polished aluminium surface

The effect of mechanical polishing of aluminium, using a final polish with 0.5 μm-Al2O3 in water, has been examined by transmission electron microscopy. Whilst the polished surface is relatively flat, about 10% of the exposed surface contains embedded Al2O3 constituting a newly-introduced major surface inhomogeneity with implications in consequent corrosion studies.