Electrochemical Evaluation of Corrosion Resistance of Trivalent Chromate Conversion Coatings with Different Organic Additives

Abstract

The corrosion resistance of electrogalvanized steels with trivalent chromate conversion coatings is investigated electrochemically to analyze the effect of organic additives on the corrosion resistance under wet-dry cyclic conditions. Three sets of polyamine additives, namely (i) imidazole and epihalohydrin, (ii) polyquaternary amine salt, and (iii) polyethyleneimine, are examined and compared. Electrochemical impedance spectroscopy and anodic stripping were employed to evaluate the corrosion resistance. Crystal-structure and compositional analyses were also applied to demonstrate the role of organic additives in controlling the structure of the zinc layer and the formation of the trivalent chromate conversion film.

Effects of Chemical Compositions on Plating Characteristics of Alkaline Non-Cyanide Electrogalvanized Coatings

“…Some prior works have pointed to deposition conditions, including current density, plating bath formulation, and plating duration as factors influencing the morphology developments of electrogalvanized deposits [ 11 , 26 , 27 ]. Surface morphology of zinc coatings is found to play an important role controlling their corrosion properties [ 28 , 29 ].…”

Electrochemical evaluation of mucilage and cochineal pigments as a hybrid film coating on aluminum surfaces

“…The Opuntia streptacantha cactus, native to central Mexico, was used in this study. Cladodes aged between 2 and 3 years were considered since they contain the highest concentrations of mucilage, according to previous studies [29]. Mucilage extraction was performed according to Sepúlveda et al [30].…”

Effects of nano-SiO2 and trivalent chromium conversion on corrosion resistance of NiZn-plated steel: towards a multilayer coating for steel protection

“…The conventional approach to improve the corrosion resistance of ZnNi coating is to fabricate the topcoat as conversion coating (trivalent chromate conversion coating [CCC]). The trivalent CCC has been used widely to passivate zinc alloys (Osborne, 2001) and zinc-coated steel (Wanotayan et al , 2018; Huong et al , 2019a). In the previous work by salt spray test (Huong et al , 2019a), we observed the appearance of white rust after 1 h and 400 h for Zn/steel and CCC/Zn/steel samples, respectively.…”