Abstract
<jats:p>This paper presents the results of developing a technology for electrodeposition of tin-zinc (Sn–Zn) alloy coatings from an alkaline electrolyte. The study aims to replace toxic cadmium and lead coatings with an environmentally friendly alternative while maintaining functional performance. The optimal electrolyte composition was determined: Na2SnO3 (0.14 – 0.16 mol/l), ZnO (0.05 – 0.07 mol/l), NaOH (90 – 110 g/l), sodium citrate (10 – 15 g/l), and sodium lauryl sulfate (0.8 – 1.2 g/l). Deposition parameters were established as follows: current density of 1.0 – 1.2 A/dm2, temperature of 40 – 45 °C, and pH 11.0 – 11.5, achieving a coating growth rate of 12 – 15 μm/h. At a current density of 1.0 A/dm2 and temperature of 40 °C, the zinc content in the coating reached 30 %, enabling cathodic protection of the substrate and the formation of a barrier layer. The maximum current efficiency (78 – 82 %) was achieved with 10 g/l sodium citrate and 1 g/l sodium lauryl sulfate. The coatings exhibited corrosion resistance exceeding 1000 hours in a 3.5 % NaCl solution and 600 – 800 hours in salt spray conditions, microhardness of 880 – 1177 MPa, a friction coefficient of 0.2 – 0.3, and transition resistance of 15 – 25 μΩ·cm. The addition of sodium citrate improved the deposit morphology, while sodium lauryl sulfate reduced surface roughness and suppressed hydrogen evolution. The study demonstrates that Sn–Zn coatings surpass traditional Sn–Pb counterparts in corrosion resistance and environmental safety.</jats:p>