The Holes of Zn Phosphate and Hot Dip Galvanizing on Electrochemical Behaviors of Multi-Coatings on Steel Substrates

The aim of this investigation is focused on the evaluation distinctive coatings commonly applied in automotive industry. resulting corrosion behavior analyzed by using electrochemical impedance spectroscopy (EIS), equivalent circuit (EC) and potentiodynamic polarization curves. novelty concerns a comparison between tricationic phosphate (TCP), cataphoretic electrodeposition (CED) an epoxy layer, TCP + CED HDG (hot-dip galvanized) multi-coatings. Both naturally deposited defect-induced damage (incision) are examined. experimental parameters current densities indicate that multi-coating system (HDG layers) provides better protection. planar porous electrode behaviors responsible to predict mechanism majority samples Although induced-damage reveal resistances decreased up 10×, when compared with no damaged samples, same trend protection maintained, i.e., < CED. It also found verified observed subjected under salt spray condition (500 h). not deleterious aspect resistance. more intimately associated initial thickness coating, while resistance adhesion layer coating. results relative cost-to-efficiency coating density ratios fact necessary top clear applications HDG/TCP systems exhibit best results.