ELECTRODEPOSITION BEHAVIOUR OF CADMIUM TELLURIDE FROM CHOLINE CHLORIDE-UREA IONIC LIQUIDS

This paper reports the electrodeposition of Cd and CdTe films on Pt using ionic liquids based on choline chloride: urea eutectic mixture (ChCl-urea, 1:2 moles) in the 25-60 0 C temperature range. TeO 2 and CdCl 2 were dissolved in ChCl:urea ionic liquid at concentrations in the range of 0.1-0.5mM and 50-100mM, respectively. The mechanism of Cd and CdTe electrodeposition was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. In the case of simultaneous presence of Cd 2+ and Te 4+ ions in ChCl-urea ionic liquid as supporting electrolyte the recorded cyclic voltammograms had more complex shapes. On the cathodic scan the massive deposition of CdTe took place. On the anodic branch of this voltammogram two oxidation peaks occur evidently, the first one being certainly due to the dissolution of CdTe compound deposit. The second anodic peak is probably dissolution of a CdTe compound riched in Te or even a dissolution of pure tellurium firstly deposited. In a series of experiments we studied the electric conductive properties of CdTe films freshly prepared.The electrolyses for films deposition were also carried out using platinum sheets in ionic liquid without stirring

The Influence of Reflowing Process on Electrodeposited Sn-Cu-Ni Lead-Free Solder Alloy

Sn-Cu-Ni lead-free solder alloy electrodeposited on copper substrate from a deep eutectic solvent (DES)-based electrolyte under direct current (DC) and pulsed current (PC) was subjected to a reflowing process at the industrial company MIBATRON S.R.L. (Otopeni, Romania). The alteration of the alloy’s composition and anti-corrosive properties upon exposure to the reflow process were investigated via Scanning Electron Microscopy (SEM-EDX), X-ray diffraction (XRD), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Corrosion studies conducted in sodium chloride solution revealed that the system obtained under the DC plating mode (Sn-Cu-Ni-DC) exhibited enhanced anti-corrosive properties compared to the system obtained under PC (Sn-Cu-Ni-PC) after reflowing. However, prior to reflowing, the opposite effect was observed, with Sn-Cu-Ni-PC showing improved anti-corrosive properties. These changes in anti-corrosive behavior were attributed to the modification of the alloy’s composition during the reflowing process

Experimental Study on the Corrosion of Carbon Steel and Aluminum Alloy in Firefighting Protein Foam Concentrates

The corrosion of mild steel and Al alloy in Fomtec P 6% and 6% P Profoam 806 protein-based foam concentrates was investigated. Weight-loss data for steel showed corrosion penetration of 0.745 mipy in Fomtec and 2.269 mipy in Profoam, whereas for Al alloy the penetration levels were 0.474 and 1.093 mipy, respectively. Scanning electron microscopy and energy dispersive X-ray spectroscopy allowed characterization of the metallic surface covered or free from corrosion products. Values of corrosion potential, corrosion current density and corrosion penetration were calculated by using potentiodynamic polarization curves. Electrochemical impedance spectra illustrated the change in polarization resistance during anodic polarization. Data obtained by accelerated electrochemical methods confirm the greater aggressiveness of the Profoam concentrate compared to Fomtec concentrate