The effect of magnesium and zinc on indium cementation kinetics and deposit morphology in the presence of and without nonylphenylpolyethylene glycol

Abstract

Indium cementation on magnesium and zinc at 60 °C and pH 1.2 in the presence and absence of nonylphenylpolyethylene glycol (D1) is investigated. Indium cementation follows first-order kinetics in all experiments. The cementation agent affects indium cementation rate, a side reaction of hydrogen evolution and the morphology of the obtained deposit. Both highest cementation rate and most intensive hydrogen evolution accompanied with the highest dissolution of the cementation agent are found during indium cementation on magnesium. Surfactant D1 substantially inhibits all these processes. The rate of indium cementation on zinc in the presence and absence of D1 is 1.5 or 1.8 times lower compared with that on magnesium. The variation of the fraction of deposited indium with time was examined according to the shrinking core model. A combination of ash diffusion model and chemical reaction model controls indium cementation on magnesium, while the chemical reaction model dominates during indium cementation by zinc. Indium deposit morphology depends strongly on the cementation agent. A thick layer of indium (with large or small cracks as well as with formations of bubbles and flakes) is observed on the magnesium surface. A compact smooth deposit of fine crystallites is found on zinc. The presence of D1 causes deposition of more compact and refined deposits on both cementation agents. The obtained results show two alternatives: using zinc-magnesium alloy and temperature higher than 60 °C to increase indium cementation rate on zinc or using low temperature and magnesium as a cementation agent of indium in the presence of surfactant D1. • The cementation agent affects indium cementation rate, a side reaction of hydrogen evolution and deposit morphology. • The highest cementation rate and dissolution of the cementation agent are found during indium deposition on magnesium. Surfactant D1 substantially inhibits these processes. • The indium cementation rate on zinc in the presence of and without D1 is 1.5 or 1.8 times lower compared with that on magnesium.