鋼酸化膜の自動還元挙動と初期錆との関係

抄録

Resistance to initial atmospheric corrosion of commercially produced mild steel depends much on the property of oxide film which was formed on the surface when the steel was taken out of the annealing furnace.
It was found that the stability of oxide film could be determined by the time transition of the corrosion potential during immersion of a sample in a neutral solution. That is, when the sample was immersed in oxygen-free borate/HCl buffer solution of pH 7.65, both initial corrosion potential (E₀) and autoreduction time of oxide film (τ) could be adopted as the parameters for the stability of oxide film.
The shorter the time τ or the less noble the initial potential E₀ the greater the rate of rusting in humid air.
Moreover, an experimental relation 1/τ=7×10^-8 exp (-41.6E₀) was obtained between τ and E₀. If we assume that local cathodic reactions are identical for all the samples, the aboverelation could be derived from the theory of electrode reaction.