The influence of glycerol as an additive in Zinc-Manganese alloy coatings formed by electrodeposition

Abstract

The aim of this investigation is to evaluate the influence of glycerol (a nontoxic additive) on Zn-Mn coatings formed by electrochemical deposition. The influence of glycerol (GLY) on the electrodeposition of Zn-Mn alloys on Pt from acid baths was studied by cyclic voltammetry. The coatings were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The Zn-Mn alloys prepared in the absence or presence of this additive showed similar voltammograms except when using GLY and boric acid (BA) concentrations at 0.63 and 0.24 M, respectively. The current efficiency of the Zn-Mn electrodeposition process ranged from 5 to 41%, due to the lowest and highest concentrations of GLY and BA, respectively. SEM images of deposits obtained at -1.53 V from baths containing 0.08-0.48 M GLY were dendritic, while those formed in the presence of 0.63 M GLY showed that GLY acted as a brightener at this concentration. The XRD analysis showed that the electrodeposits contained Zn, Mn, oxides as well as alloys of various compositions. GLY acted as a grain refiner and inhibited the codeposition of Zn with Mn and the formation of oxides.

Durability of Acrylic Cataphoretic Coatings Additivated with Colloidal Silver

“…In fact, several works have turned to the optimization of the process equipment [12,13] and parameters, such as the curing temperature [14] and the deposition voltage [15], in order to further improve the behavior of the cataphoretic layers. The electrodeposition process has exhibited high versatility, as it has been applied to different metal substrates, such as Zn-Mg alloys [16,17], Ti-Mo alloy [18], aluminum alloys [19][20][21], and steel alloys [22]. Furthermore, this method has also been evaluated in synergy with different types of pre-treatments [23,24] to improve the adhesion and durability of the coating.…”