Production of Cu-Sn Alloy Coatings Onto AISI 1020 Carbon Steel Substrate Using Sodium Citrate Bath and SPC Electrodeposition

In the present work, we explored the production of Cu-Sn alloy coatings with anti-corrosive properties using simple pulse current (SPC) electrodeposition. The effects of the pulse parameters - pulse frequency (F) and duty cycle (γ) - on the surface characteristics of the coatings produced at a constant average current density value were evaluated to verify the corrosion protection performance of these coating systems in a saline medium. Coatings with small grains, high Sn content, a single Cu6Sn5 phase microstructure, and reduced porosity were obtained by increasing F and γ, improving the cathodic current efficiency and charge transfer resistance in the NaCl 3.5%w/v. The most protective coating, produced at F = 1500 Hz and γ = 50%, showed a Sn content near that of commercial bronze and a charge-transfer resistance of 4097 Ω cm2, which is approximately 2.5 times higher than the resistance of a protective alloy obtained by DC electrodeposition.