In-situ Observation of Corrosion Initiation Occurring on NaCl Nanoparticles-deposited Carbon Steel Surfaces

Abstract

Raman micro-spectroscopy was conducted for in-situ observation of atmospheric corrosion occurring on carbon steel surfaces, on which NaCl nanoparticles with a size of < 1 µm were deposited, under the controlled relative humidity at room temperature. Increasing relative humidity induced the formation of amorphous-FeOOH at a micro-droplet of NaCl solution where an NaCl nanoparticle was dissolved on the steel surface, and the initiation time of the corrosion generation decreased with increasing relative humidity. Drying treatment at 100ºC for 600 s resulted in modification of the surface condition of carbon steels and obstructing the corrosion initiation at high humidity conditions but reducing the initiation time at low humidity conditions.