Abstract
UDC 621.357
DOI https://doi.org/10.5281/zenodo.1297937
Deep eutectic solvents (DESs) are nowadays considered to be very promising analogues of room temperature ionic liquids. DESs can make a significant contribution to the development of novel efficient, economic, and environmentally friendly processes, particularly in surface engineering and electroplating. The electrodeposition of Ni–TiO2 composite coatings from an electrolyte based on a deep eutectic solvent, ethaline, has been studied in this work. Titania particles were introduced into the plating bath in the form of Degussa P 25 nano-powder. The content of titania in electro-deposited composite coatings was shown to depend on the stirring rate, the current density, and the TiO2 concentration in the electrolyte; it can reach ~ 2.35 wt.%. Both the microstructure and the surface morphology of the obtained composite layers were characterised. The formation of the nanocrystalline nickel matrix was detected. The introduction of TiO2 particles into nickel-based coatings resulted in an increase in the microhardness of deposits. The data obtained by electrochemical impedance spectra technique revealed an improvement in the corrosion resistance of coatings due to titania particles incorporation into deposits. The Ni–TiO2 composite coatings manifested a photocatalytic activity towards the reaction of photo-chemical degradation of methylene blue organic dye in water solution.
Keywords: electrodeposition, nickel, titania, composite coating, deep eutectic solvent.