Electrodeposition of Zn-Fe Alloy from Non-Cyanide Alkaline Sulphate Bath Containing Tartarate

Electrodeposition of Zn-Fe alloy from an alkaline sulphate bath containing tartarate has been carried out. The effect of plating variables on the composition of alloy and on cathodic current efficiency was studied. The cyclic voltammetric studies carried out to know the mutual co-deposition of zinc and iron. Hardness and the surface morphology of the alloy deposits were found to be dependent on the iron content in the alloy. An alloy containing 20% wt. Fe showed smooth, uniform and finer grained deposits. Under the optimum composition and operating conditions, Zn-Fe alloy deposition from alkaline sulphate bath containing tartarate followed anomalous depositing process.

Methods to Determine the Current Efficiency in AC Electrolysis

The paper presents several methods (analytical, electromechanical and electronic) for determining the cathodic current efficiency of the metal deposition processes carried out by AC or pulse current. Based on the results of own experimental researches (for indium, cadmium, nickel, tin and zinc), the appropriate equations are given and the distribution of both faradaic and non-faradaic parts of charge (charging of the electrode double layer) is calculated.

The Research about EDTA Plating Solutions of Non-Cyanide Copper Plating

Six formulae of plating solution were studyed in the experiment. The first formula was cyanide plating solutions. The others formulae based on the EDTA as primary complexing agent, C6H5O7K3•H2O and KNaC4H4O6•4H2O as auxiliary complexing agent. Bath quality of the six formulae were examined and Compared. The results show that the EDTA system improve the ability of throwing power, covering power, current efficiency and reduce the bath voltage. In some ways, the performance of EDTA system were better than cyanide plating solutions, such as the deep plating ability, dispersing power, cathodic current efficiency.

Effect of Saccharin Addition on the Electrodeposition of Nickel from a Watts-Type Electrolyte

The influence of saccharin addition on cathodic polarization, cathodic current efficiency, hardness, surface morphology, and internal stress of nickel electrodeposition from a Watts-type plating bath was studied in this work. The results show that the addition of saccharin may enhance the cathodic polarization, modify the surface morphology, increase the hardness, and decrease the tensile stress. In particular, when the concentration of saccharin is 0.4 g/L, the surface of nickel deposition is smoothest. When the concentration of saccharin is 0.05 g/L, the hardness of nickel deposition is highest.

High Temperature Electrolysis of Ti and its Alloys with a DC-ESR Unit

Direct electrolysis of Ti and its alloys has been attempted by the process using a DC-ESR unit. The concept of the process is explained in detail, and the expected key issues are commented. Liquid Ti metal was obtained in a CaF2-CaO-TiO2 bath, and electrolysis by using a new type of the electrolytic cell was also tried. Ti-Al alloy was successfully deposited in a CaF2-CaO-TiO2-Al2O3 bath, whereas Ti-Si alloy was not obtained in a CaF2-CaO-TiO2-SiO2 bath yet. Ti-Fe alloy was extracted in CaF2-CaO-TiO2-FeO bath of a particular composition. A common correlation between the cathodic current efficiency and the average consumed electric power seen in the Ti, Ti-Al and Ti-Fe electrolysis suggested the importance of sufficient temperature in the process. The bath composition also affected the temperature through the change in the electric conductivity of the bath.

Dependence of Titanium Deposition upon Its Ionic State in Molten Salt

The ionic valence of Ti changed with electrorefining process of Ti in a bath equi-molar mixture of NaCl-KCl containing TiCln(n=2 or 3); The average valence was about 2.3 initially, and became about 2.1 after electrolysis. The cathodic current efficiency was getting better with electrolysis. It should be necessary to maintain the average ionic valence lower for efficient electrolysis in the molten salt. The dominant Ti ion and its electrode reaction changed with the addition of NaF-KF in the molten salt; The average valence shifted from about 2 to about 3, and the total amount of Ti in the bath decreased. The result indicates the disproportionation reaction: 3Ti2+= Ti + 2Ti3+is induced by the fluoride addition. The quantity of electricity for Ti deposition changed consequently, and the purity of the Ti deposit was also affected.