Strain Enhanced Corrosion in the Iron-Caustic System Available to Purchase

Straining electrode experiments were performed to investigate the nature of strain enhanced corrosion of iron in caustic electrolyte. The strain enhanced corrosion rate was generally linearly dependent on applied strain rate, and its potential dependence paralleled that of steady-state polarization behavior on non-straining electrodes. Data was presented as $ℓ˙/ϵ˙$ ratios, in which $ℓ˙$ is the corrosion rate in cm/s and $ϵ˙$ is the corresponding strain rate. This ratio, which was shown in a previously published theory to be numerically equal to the crack advance per film rupture event during film rupture SCC, depended on electrochemical variables such as electrolyte concentration and temperature in a manner similar to the kinetics of caustic cracking. Conditions which are known to be marginal in producing caustic cracking resulted in values for $ℓ˙/ϵ˙$ of about 10⁻⁷ cm, in excellent agreement with a previously developed theory. It was concluded that strain enhanced corrosion in this system results from repetitive film rupture and repair during straining.