Aluminum containing Na2CrO4: Inhibitor release on demand

The paper presents a new concept of metallic materials containing inhibitor, able to inhibit corrosion as it initiates. Al particles with uniformly dispersed sodium chromate (0.5-20 wt%) were produced by high-energy ball milling followed by cold compaction. Cyclic potentiodynamic polarization tests and surface analysis after constant immersion tests revealed a significant improvement in corrosion behavior due to the sodium chromate addition up to 5 wt%. Improved corrosion behavior was attributed to the release of inhibitor as corrosion occurred. X-ray photoelectron spectroscopy indicated presence of the Cr3+ in the passive film.