In-situ observations of crack nucleation and growth during stress corrosion by scanning vibrating electrode technique

A scanning vibrating electrode technique (SVET) was applied to make in-situ observations of stress corrosion cracking (SCC) in type 304 steel single crystals exposed to a 2.5 kmol m−3 H2SO4+0.4 kmol m−3 NaCl solution at room temperature. The three-dimensional (3-D) plots of corrosion current density during SCC can be successfully displayed with the SVET. Under the applied stress conditions of yield strength and above, the anodic current is observed locally at the site of crack nucleation along the mechanically induced slip-steps. Following the crack nucleation, the anodic current peaks disappear with the crack growth on {110} planes, regardless of the test condition. It is, therefore, concluded that the SVET can be applied to make in-situ observations of crack nucleation and growth during stress corrosion.