Investigation of the effect of additive chemicals for zinc and nickel metals by electrochemical analysis method in various deep eutectic liquids

In this thesis, pure nickel and zinc coatings were produced using deep eutectic liquid (DES), and then the coatings were reworked in these baths by mixing different additive chemicals. Coatings produced with additive chemicals were compared with pure coatings, and their effects on physical and morphological properties were investigated. The primary purpose of this thesis is to improve the physical and morphological properties of pure nickel and zinc coatings with the positive effect of additive chemicals added to the coating baths. In the thesis study, two main deep eutectic liquids (DES) were prepared in 50mL beakers where the coating process would take place. The first is zinc chloride: ethylene glycol, which is formed with a mixture of binary components in a 1:4 molar ratio, respectively, and the second is choline chloride: ethylene glycol: nickel chloride Hexa hydrate DES solution, which is prepared with 1:4:0,4 in molar ratio, respectively. A total of eight DESs were produced by adding potassium hydrogen tartrate (PHT), sodium citrate tribasic (SCT), and ammonium chloride (NH₄Cl) additives into the produced DESs, and the physical properties of these DESs such as conductivity and pH were examined. Cyclic voltammetry and chronoamperometry techniques were used to examine their electrochemical properties. Zinc and nickel plating were done on mild steel by using DES solutions, whose physical and electrochemical properties were examined. Surface roughness and thickness measurement, hardness measurement, SEM-EDS analysis, and XRD analysis of the obtained coatings were performed. After the analysis, the coatings made by adding additives were compared with the additive-free systems. As a result of the measurements and analyzes, it was determined that the NH₄Cl additive chemicals increased the hardness, thickness and roughness of the coating and changed the grain orientation and size. Consequently, the advantages and disadvantages of employed additives for the electrodeposition of zinc and nickel were examined, and the results were given.