High rate anodic dissolution of nickel in sodium nitrate electrolytes was studied under controlled hydrodynamic conditions in order to investigate the influence of electrolyte concentration, pH and temperature on surface brightening under conditions comparable to electrochemical machining. Dissolution experiments were performed on a rectangular flow channel cell through which the electrolyte was pumped at a constant linear velocity of 1000 cm s−1. Results show that the onset of surface brightening depends on concentration and temperature of the electrolyte but is little affected by pH. The data are consistent with a previously described salt precipitation model for surface brightening.
Dr. Madhav Datta and Landolt, D., “On the influence of electrolyte concentration, pH and temperature on surface brightening of nickel under ECM conditions”, Journal of Applied Electrochemistry, vol. 7, pp. 247–252, 1977.