Optimization of pulse electrodeposition parameters for enhanced resistance to corrosion and hydrogen permeation of zinc coatings

Corrosion and hydrogen permeation resistance of pulse electrodeposited Zn coatings were correlated with coating micro-texture and strain. The maximum and minimum corrosion resistance were noted for D6F75 (duty cycle 60; frequency 75 Hz) and D8F25 (duty cycle 80; frequency 25 Hz), respectively. The D6F75 coating exhibited a higher fraction of low-energy low-angle grain boundaries (LAGBs) and a preferred texture of $\left(3\overline{1}\overline{2}1\right)$ whereas the D8F25 coating exhibited comparatively low LAGBs fractions and$\left(2\overline{1}\overline{1}0\right)$ orientation. High resistance to hydrogen permeation exhibited by the D6F75 coating was attributed to hydrogen trapping within the coating, which reduced the micro-strain within the coating and diminished the hydrogen concentration gradient, thereby promoting greater surface recombination.