Electrochemical impedance spectroscopy study of corrosion of painted cold-rolled and electrogalvanized sheet steel for automotive use.
Dattilo-M; Prater-RB, Jr.; Miller-VR
Rolla, MO: U.S. Department of the Interior, Bureau of Mines, RI 9324, 1990 Jan; :1-11
The U.S. Bureau of Mines has been conducting research on the use of waste-derived zinc as a partial replacement for pure zinc in the electrogalvanizing process. The end product of this process is automotive sheet, which has enhanced cosmetic protection over previously used cold-rolled (cr) steel. In this study, primer- coated specimens of cr and electrogalvanized (eg) steel were subjected to the on-vehicle environment and monitored periodically by electrochemical impedance spectroscopy (eis) during immersion in 1m nacl solution. The results of these tests were compared with immersion-only conditions. Scanning electron microscope (sem) and energy-dispersive x-ray (edx) techniques were also used to evaluate the corrosion processes and compare them with atmospheric exposure specimens. Eis was found to measure the corrosion associated with on-vehicle exposure, thus providing an excellent screening technique for evaluation of the performance of eg automotive sheet steel.
Coatings; Paints; Corrosion; Automobiles; Electroplating; Steels; Electrochemistry; Impedance; Spectroscopy; Selection; Electron microscopes; Evaluation
IH; Report of Investigations
Rolla, MO: U.S. Department of the Interior, Bureau of Mines, RI 9324