Copper cementation on zinc and iron mixtures: Part 1: Results on rotating disc electrode

Cementation of copper ions onto a rotating disc electrode (RDE) of zinc and iron, either alone or associated as sacrificial metals is studied. The influence of operating temperature (10–50 °C range) confirms copper cementation limitation by mass transfer on iron and zinc, with the systems presenting mass transfer coefficients in the range 8–50 · 10− 5 m s− 1. Electrode potential changes indicate that the cathodic surface increases as cementation proceeds, where copper cement presents nearly 10 m2 g− 1 of specific surface. This results in a kinetic acceleration, underlined by the copper/iron system. These results also highlight that zinc metal is the main site of hydrogen evolution and thus lessens iron corrosion during hydronium ion reduction. Tests of iron protection by zinc via galvanic coupling did not fully succeed as iron is still released in the solution.

Research Highlights
► Copper cementation limitation by mass transfer on iron and zinc is confirmed.
► Electrode potential evolutions point out cathodic surface increases, implying a kinetic acceleration.
► Zinc is the main target of dihydrogen evolution and thus lessens iron corrosion.