Cu Plating with Sn and Subsequent Bronze Formation under Mild Conditions

Abstract

In a well-known bronze plating experiment, a Cu coupon is subjected to Sn plating and heating with a Bunsen burner. Currently, aqueous NaOH or HCl is typically used as the plating solution; however, the use of a strong acid or base provides operational risks, particularly in educational settings (e.g., schools). Herein, we introduce a modified method that uses aqueous NaHSO4 as the plating solution. This method reduces the operational risks and allows for the smooth deposition of silver-white Sn onto the Cu coupon in a higher yield than that obtained by the HCl method, which uses 30 times the concentration of the solute. When the Sn-plated Cu coupon is heated, it changes to bronze plating. This experiment is ideal for high school students, as it allows them to observe metal plating and solid diffusion.