Innovative deep eutectic solvent approaches in zinc electroplating for morphology enhancement, superior strength, and corrosion protection

The growing number of galvanized scrap due to the extensive application of galvanized products has led to a significant increase of the zinc content in the electric furnace dust, so how to realize high-value comprehensive utilization of zinc-containing dust has become a key issue for the sustainable development of the iron and steel industry. Based on the principle of recycling zinc resources, this study proposes an innovative full life cycle process for the preparation of electro-galvanized sheet using zinc-containing dust as raw material and deep eutectic solvents (DESs) as medium. Zinc plating was successfully prepared on duplex steel automobile plates using choline chloride-urea DES (Reline) as the electrolyte, and the modifying effects of different concentrations of nicotinic acid (NA) on the electrochemical system of the solution and the prepared plating were also investigated. The results show that the addition of 0.06 M NA to the system can modulate the deposition morphology of the plating layer, leading to the generation of ultrafine grains, and the surface densities and flatness are significantly improved. Besides, the addition of NA to the system increased the hardness value by 67.5 % and reduced the coefficient of friction by 38.8 % compared to the plating obtained in the system without additives; the corrosion rate decreased from 0.374 mm·a-1 to 0.023 mm·a-1, and the corrosion mechanism of the zinc layer was a direct dissolution process of zinc. This study realizes the morphology regulation of electroplated zinc plating, and greatly improves the aesthetics, mechanical properties and corrosion resistance of the plating at the same time, also the preparation process is in line with the requirements of the green development, which can provide a novel solution for the automotive high-quality plating.