Synthesis and performance of Zn–Ni–P thin films

The electroplating of Zn–Ni–P thin film alloys from a sulfate bath containing phosphoric and phosphorous acid was investigated. The bath composition and the deposition parameters were optimized through Hull cell experiments, and the optimum experimental conditions were determined（p H = 2, temperature = 298–313 K, zinc sulfate concentration =30 g·L^-1, EDTA concentration = 15 g·L^-1, and current density = 1.0–2.0 A·dm^-2）. The SEM analysis of the coating deposited from the optimum bath revealed fine-grained deposits of the alloy in the presence of EDTA. Optical microscopy analysis indicated an electrodeposited thin film with uniform thickness and good adhesion to the steel substrate. The good adherence of the coatings was also demonstrated by the scratch tests that were performed, with a maximum determined value of 25 N for the critical load. Corrosion resistance tests revealed good protection of the steel substrate by the obtained Zn–Ni–P coatings, with values up to 85.89% for samples with Ni contents higher than 76%. The surface analysis of the thin film samples before and after corrosion was performed by X-ray photoelectron spectroscopy（XPS）.

Influence of the operating parameters over the current efficiency and corrosion rate in the Hall–Heroult aluminum cell with tin oxide anode substrate material

A systematic laboratory study was conducted on current efficiency and corrosion obtained in cryolite-alumina melts with SnO2-Sb203-CuO ceramic inert anodes. The current efficiency （CE） was determined by measuring the total amount of oxygen evolved at the anode and was found to be ~ 95%. The influence of operating parameters （inter-elec- trode distance, temperature and current density） was evaluated. The quantitative interdependencies as well as the ranges of CE optima[ values were established （2-3 cm, 940-960 ℃ and 0.7-0.8 A.cm 2）. The corrosion process of these anodes was evaluated by the mass loss method. The evaluation also took care of the corrosion data, as the prob- lem of the anode corrosion appeared to be the main obstacle for the use of those anodes in the commercial cells.Low-ering of the ACD up to 2 cm did not aggravate anode corrosion.

Electroreduction of Tungsten Oxide（VI） in Molten Salts with Added Metaphosphate

Tungstate ions WO4^2- are not electrochemically active in chloride melts. Upon introduction of PO3 ions into the melt, two waves appear in the voltammograms at potentials -0.1-- -0.2 V and -0.3-- -0.5 V vs. Pb/Pb2＋ reference electrode. With a PO3- concentration ratio of 0.01〈[PO3-]/[WO42-]〈0.18, the potentiostatic electrolysis product of WO42 at the above mentioned potentials is metallic tungsten; a NaPO3 concentration increase for ratios [PO3-]/[WO42-]〉〉0.18 results in tungsten phosphide in electrolysis product. Cyclic voltammograms and dependence of half-peak potentials on electrode polarization rate indicate the irreversible character of the electrode process. Elec- trode process modeling allows us to state that the first wave in the voltammogram of KC1-NaC1-Na2WOa-NaPO3 sys- tem corresponds to tungsten oxychlorides discharge while the second wave appears due to the discharge of di- tungstate ions. In the voltammograms of Na2WOa-NaPO3 melts, reduction wave was observed at -1.1-- -1.2 V po- tentials. Proportionality of limiting current to NaPO3 concentration, constancy of ld/V1/2 ratio, and IJnFc constant ki- netic value equal to （8.3--9.5）×10-5 cm/s for steady-state wave indicate that electrode process rate is limited by elec- trochemically active particle diffusion to the electrode. Nascent ditungstate ions become electrochemically active in the overall electrode process. Charge transfer stage is reversible.

Synthesis, Characterization and Thermophysical Properties of Three Neoteric Solvents-Ionic Liquids Based on Choline Chloride

The authors prepared,characterized and preliminary studied the properties of some neoteric solvents-ionic liquids based on choline chloride,i.e.,three ionic liquids based on the eutectics of choline chloride（2-hydroxyN,N,N-trimethylethanaminium chloride） with,respectively,urea,malonic acid and citric acid.The obtained mixtures were clear and colorless ionic liquids at room temperature.The thermophysical properties,namely,density,viscosity,and electrical conductivity of these mixtures were investigated as a function of temperature within a range of 298-353 K.Correlations for the temperature dependence of the measured properties were generated and discussed in terms of Arrhenius theory.Finally the electrochemical windows of the eutectic liquids were determined.

Electrochemical Study and Electrodeposition of Copper（I） in Ionic Liquid-reline

The authors made the electrochemical studies on the electrode processes during copper electrodeposition with ionic liquids-reline as an electrolytic medium. Reline is a commercial name for a eutectic mixture of choline chloride and urea（1：2, molar ratio）. This new proposed method of copper deposition is an ecological one because the ionic liquids are recyclable, non-volatile and non-toxic. Cyclic voltammetry investigations were conducted at 343 and 353 K in choline chloride-urea（Reline） deep eutectic solvent with single salt CuCl（generally in 0.05--0.38 mol/L concentration range）. Electrochemical impedance spectroscopy investigations were conducted in choline chloride- urea ionic liquid with CuCI（0.05 mol/L）. We investigated both cathodic and anodic processes of Cu＋ ions at different sweep rates in this new electrolytic system based on choline chloride. We have proposed by this an alternative to the classical copper electrodeposition. Coefficient of diffusion, Do, for the system Reline-CuCl is presented and the value of D0 is 1.22× 10^-8 cm2/s.

Transport Properties of Alkali Fluoride High Temperature Ionic Liquids and Application of Theories of Viscous Flow

The transport properties of several alkali fluoride high temperature ionic liquids（LiF, NaF, KF, RbF and CsF） were studied in a range of 980-1400 K and the temperature dependences of the viscosity and density were interpreted, in agreement with the classical equations characterizing the viscous flow（Arrhenius, Batchinski, Eyring and Frenkel）. The experimental results reveal the validity of these equations even at high temperatures, suggesting that no significant structural changes of alkali fluorides occurred in the studied temperature range. Our results clearly demonstrate that the mentioned thermo-physical properties can be used as powerful tools in the further investigations of the ionic interactions governing the alkali fluoride molten salts.