Kinetics and deposit morphology of copper cementation onto zinc, iron and aluminium

The kinetics of copper cementation onto iron, zinc and aluminium powders at 60 °C and pH=1 have been examined along with the morphology of the deposited copper. The three reductants cemented copper very differently:(a) ium gave substantially slower cementation that either iron or zinc and also dissolved significantly less. This passivity of aluminium is due to the oxide layer on its surface; ghest cementation rate was obtained using zinc; however, intensive hydrogen evolution on the deposited copper leads to high consumption of zinc; as the best substrate for cementation, it deposited copper at ∼70% the rate of zinc but did not react significantly with the acid leading to only one quarter the consumption of zinc; rphology of copper deposits strongly depends on the cementation agent: a coherent layer of fine-grained crystallites less than 1 μm size was obtained on iron, a dendritic deposit with high porosity was obtained on zinc and globular crystallites 1–4 μm in size were obtained on aluminium.