Pitting and alkaline dissolution of an amorphous–nanocrystalline alloy with solute-lean nanocrystals

The corrosion resistance of partially devitrified metallic glasses is a critical concern for the viability of the glasses in many technological applications. Although partial devitrification is detrimental to the corrosion resistance of some metallic glasses, both the pitting and alkaline corrosion behavior of partially nanocrystalline Al90Fe5Gd5 is similar to that of its amorphous precursor. This is in spite of the fact that the microstructure of the amorphous–nanocrystalline alloy is effectively a composite consisting of f.c.c. Al crystals embedded in an amorphous matrix. Here the pitting corrosion and alkaline dissolution of the amorphous–nanocrystalline alloy is compared to that of its fully amorphous precursor, pure polycrystalline Al, and to a micrometer scale composite consisting of electrically connected pure Al wires and amorphous ribbons.