The Electrochemical Deposition Of CdZn And SnBi In Choline Chloride Ethylene Glycol

Cadmium plating coating has excellent performance in aviation and navigationdisgusting field such as excellent corrosion resistance, good lubricity, good weldability.Cadmium-Zinc alloy has extensive use in welding field. Cadmium and Zinc as alloyelement have gracious applications in semiconductor field. Tin-Bismuth alloy as anenvironmental solder has a large number of applications.Electrodeposition is a simple and effective tool in electrochemical field. Commonplating solution is aqueous system, there are several difficulties to limit its application:small potential window, easy Hydrogen evolution and easy passivation. Ionic Liquid (IL)has perfect project to solve mention-above difficulties. IL has many advantages: largepotential window, hard Hydrogen evolution and hard passivation. Choline Chloride-ethylene glycol(ChCl-EG) is not only cheap, but also stable to air and water. It alwayshas common IL’s advantages.This paper studies on Cadmium and alloy’s electrodepositing mechanics in ChCl-EG IL solution; electrodepositing Cadmium by the corrosion tests through variouscurrent densities in ChCl-EG IL solution and discussing the relationship between anti-corrosion and current density, explaining the reason; analysis different electrodepositingCadmium-Zinc and Tin-Bismuth alloy parameters, such as molar ratio, potential andtemperature.Electrochemical measurement expresses that Cadmium nucleation/growth modeis an irreversible electro-transfer process and a two-dimensional instantaneousnucleation/growth mode. Cadmium-Zinc and Tin-Bismuth alloy growth mode is aninduced codeposition process.The grain size of electrodepositing Cadmium and current density are inverselyrelation in low current density area, however the grain size of electrodepositingCadmium is proportional to current density in high current density area. The surfacetopography is also affected by the current density. When the current density is moderate,the coating’s anti-corrosion is larger than others because of small contact area. Themorphologies of Cadmium-Zinc alloy were cauliflower-like. This is that the surface were composed of small dendrites, the branches developed at the edges and repeatedthis process. When the potential becomes negative, the electrodepositing rate of Tinincreases to thin the grain size, at the same time, the electrodepositing rate of Bismuthdecreases to coarsen the grain size.The atom content of Cadmium could varies from45%to83%in the Cadmium-Zinc alloy by controlling the Cadmium/Zinc molar ratio (from1to5), temperature(from50°C to90°C) and potential (from-1.30V to-1.70V). The atom content ofBismuth could varies from37%to66%in the Tin-Bismuth alloy via adjusting the Tin/Bismuth molar ratio (from1to5), temperature (from50°C to90°C) and potential (from-1.30V to-1.70V), which could obtain58wt%Tin/Bismuth alloy.