Exfoliation corrosion in a piece of aluminium. The piece's depth is around 5 mm. Exfoliation corrosion is a type of intergranular corrosion which spreads along the crystallization surfaces, which causes the material to split in the appearance of layers.
<a href="//commons.wikimedia.org/wiki/User:Kadellar" title="User:Kadellar">Carlos Delgado</a>
<span class="int-own-work" lang="en">Own work</span>