Such materials are characterized by highly heterogeneous microstructures, which provide microscopically tailored macroscopic diffusive, thermal or mechanical responses under ideal damage-free conditions. However, due to their inherently heterogeneous microstructure, consisting of material components of highly contrasting properties, such materials are susceptible to corrosion. On the subcontinuum scale, the high energy state of the internally stressed material lowers the barrier to ionization, i.e. stripping off of electrons. This leads to corrosion because of the attempt by the material to equilibrate the ionic concentration. However, not only the corrosion is detrimental, but also the gas, which occurs as a by-product.
Gas production can cause high pressure and micro-cracking or intergranular decohesion.
The pictures below show a cross-section of a 20 particle example. A microheterogeneous solid undergoing chemical attack. Mutually orthogonal time frames of the damage in the material sample after 5000 seconds. Mutually orthogonal time frames of the damage in the material sample after 50000 seconds.