Pit and flow streak formation during high rate dissolution of nickel in chloride solution has been investigated. Experiments were carried out under active and transpassive dissolution conditions using direct and pulsating current. The results obtained indicate that sulfide inclusions are the nucleation sites of pits. The growth, size distribution, and life cycle of pits are governed by the size of inclusions and their number and by dissolution conditions. Characteristic tails and flow streaks observed during transpassive dissolution with direct current are due to local disturbance of hydrodynamic conditions introduced by the presence of pits.
Dr. Madhav Datta and Landolt, D., “Pit and flow streak formation during high rate dissolution of nickel”, Journal of The Electrochemical Society, vol. 129, pp. 1889–1895, 1982.