Corrosion-Electrochemical Behavior of the TsAMSv4-1-2.5 Zinc Alloy Doped with Sodium in a NaCl Electrolyte Environment

Metallic zinc of grade Ts3 is not widely used because of its lead content of up to 2.0–2.5%. The possibility of synthesizing a new alloy based on the zinc alloy TsAM4-1 using off-grade zinc of grade Ts3 and additional alloying with metallic sodium was evaluated (as a result, the alloy designation TsAM4-1 was changed to TsAMSv4-1-2.5). The effect of sodium addition on the corrosion-electrochemical behavior of the zinc alloy TsAMSv4-1-2.5 in a NaCl electrolyte was studied using a pulse potentiostat PI-50-1.1 by the potentiodynamic method at a potential scan rate of 2 mV/s. It was shown that alloying the TsAMSv4-1-2.5 alloy with sodium shifts the potentials of free corrosion, pitting formation, and repassivation toward the positive region. With increasing chloride ion concentration in the NaCl electrolyte, the corrosion rate of the alloys increases regardless of their composition. The addition of sodium to the TsAMSv4-1-2.5 alloy reduces its corrosion rate by 10–15%. The improvement in corrosion resistance of the zinc alloy TsAMSv4-1-2.5 by 10% allows for an equivalent reduction in the thickness of protective coatings on protected products, as well as a decrease in environmental contamination by lead.