Corrosion at Nanoscale: Insights from Nanoscale Zero-Valent Iron (nZVI) Oxidation

Corrosion is one of the main causes of material degradation and failure, impacting the integrity, safety, and lifespan of materials. It also creates enormous waste of natural resources and imposes huge economic and environmental losses on society. Herein, we present new perspectives gained from ongoing investigation on oxidation and corrosion of nanoscale zero-valent iron (nZVI). It offers an ideal research model to examine corrosion mechanisms at nano- and atomic scales, which entail the formation of atomic and nanoscale capillaries, galvanic cells, and Kirkendall nanovoids. In particular, 3D electron tomography of nZVI suggests that iron corrosion starts with the coalescence of the nanoscale capillary channels. Instead of chasing surface defects (e.g., pitting), nanocapillaries are the genuine attestation for early detection and prevention of iron corrosion.