To improve the corrosion resistance of trivalent chromium coatings
trivalent chromiumzirconium hybrid coatings were prepared on 6063 aluminum alloy by using chromic potassium sulfate and zirconium sulfate
and phosphoric acidPolarization curves and electrochemical impedance spectroscopy(EIS)were used to investigate the electrochemical characteristics of chromiumzirconium hybrid coatings formed in plating solutions of different concentrations of zirconium sulfate
and better corrosion resistance was confirmedCompared with the coatings without zirconium sulfate plating and bare aluminum alloy
polarization curves showed that the hybrid coatings formed in 08—12 g·L-1 Zr〖DK〗(SO4)2 plating solution had more positive corrosion potential
and lower corrosion current density.Electrochemical parameters of EIS indicated that the hybrid coatings had higher resistance and charge transfer resistance.The morphology and composition of the coatings were examined by SEM and EDS
respectivelyThe results showed that the morphology of coatings remained almost unchanged and the coatings mainly consisted of Cr
Zr
P
and O after addition of zirconium sulfate
and the chromiumzirconium hybrid coatings were formed on 6063 Al alloy