Zirconium electrodeposition

GZO films were electrodeposited from an electrodeposition bath containing 0.29-g gadolinium halide and 0.1-g zirconium halide dissolved in a 150-mL electrolyte solution. Electrodeposition was performed at a current density of 1 mA/cm2 and under constant stirring in a vertical two-electrode cell configuration. The average rate of deposition was about 25 nm/min. 

Fig. 4.13 Square-wave voltammograms of PIGEs modified with mixtures of a zirconium-containing sample plus Zr02 (standard) and ZnO (auxiliary reference material) in contact with O.IOM VaCZ. Sample ZnO mass ratio equal to 4.422 ZnO Zr02 mass ratio equal to (a) 0.163 (b) 1.216 and (c) 5.374. Potential scan initiated at —1.45 V in the positive direction without prior electrodeposition step. Potential step increment 4 mV square-wave amplitude 25 mV frequency 15 Hz. [234]...

The most well-known electrodeposition process from the molten state is that of aluminum, which is deposited from a mixture of AI2O3 in AlF3-NaF at 965 °C. Other commercial processes involving molten salts exist and are exemplified by the deposition of tantalum and zirconium. Processes for Ti deposition from TiCl3 in KCl-LiCl entectics exist. All these escape almost completely97 from the H co-deposition problem of aqueous electrodeposition. 

Titanium can likewise be electrodeposited from nonaqueous organic electrolytes. At circa 18 °C, 1-75 iim thick coatings are deposited from electrolytes containing dimethylsulfoxide (DMSO) [169]. The baths utilized do not exhibit high stability. Zirconium, hafnium, niobium, and aluminum are also expected to afford electroplated coatings from similar composite systems. Electroplating of titanium from electrolytes based on aromatic solvent mixtures has recently been reported [171]. 

Mellors, G.W. and Senderoff, S. Electrodeposition of coherent coatings of refractory metals VII. Zirconium diboride (1971) J.Electrochem. Soc 118-1, 220-225. 

Frazer, E.J., Anthony, K.E., and Welsh, B.J (1975). Electrodeposition of zirconium diboride from oxides dissolved in molten cryolite. Electrodeposition and Surface Treatments, 169-177. 

Effect of Electrolysis Parameters on the Coating Composition and Properties during Electrodeposition of TVingsten Carbides and Zirconium Diborides... 

Trogadas and Ramani summarized the modification of PEM membranes, including Nafion modified by zirconium phosphates, heteropolyacids, hydrogen sulfates, metal oxides, and silica. Membranes with sulfonated non-fluorinated backbones were also described. The base polymers polysulfone, poly(ether sulfone), poly(ether ether ketone), polybenzimidazole, and polyimide. Another interesting category is acid-base polymer blend membranes. This review also paid special attention to electrode designs based on catalyst particles bound by a hydrophobic poly-tetrafluoroethylene (PTFE) structure or hydrophilic Nafion, vacuum deposition, and electrodeposition method. Issues related to the MEA were presented. In then-study on composite membranes, the effects of particle sizes, cation sizes, number of protons, etc., of HPA were correlated with the fuel cell performance. To promote stability of the PTA within the membrane matrix, the investigators have employed PTA supported on metal oxides such as silicon dioxide as additives to Nafion. 

Electrodeposition from sol-gel solutions containing two or more different sol-gel precursors yields hybrid films, as the sol-gel components hydrolyze and condense together forming a cross-linked structure. The hybrid films may be electrodeposited from precursors consisting of either two or more different silanes, or silane with titanium or zirconium alkoxides. 

Chapter 1 provides an overview of the current rmderstanding of the problem of corrosion. The chapter also provides a brief introduction to nanomaterials in this context. Chapter 2 discusses corrosion basics with referetrce to nanostmctured materials. Chapter 3 addresses theoretical aspects of grain size reduction on corrosion with a model example and comparison with experimental resirlts of nanocrystalline zirconium and its alloys. Chapter 4 provides a good accoimt of the relevant electrochemical aspects of nanostructured materials. The nature of passive film and its correlation with nanocrystallization are explained. Chapter 5 gives a good description of fabrication of electrodeposited nanostructured materials. 

Aniline, intercalation in layered protonic conductors, 220-229 Aromatic polycyclic molecules, use as probe molecules for mechanistic studies of sol-gel-xerogel transitions and cage properties, 400 Artificially layered ceramics, nanoscale, electrodeposition, 244-253 Asymmetrically layered zirconium I iqtonates, 166-176 experimental procedure, 174-176 interlayer spacings of compounds, 170r schematic representations of layers, 169/ synthesis, 167-168... 

Several of the electroanalytical methods discussed elsewhere have been successfully applied in non-aqueous solvents. The other main interest centres round the electrodeposition of the active metals, Na, Ca, Al, etc., for which mixtures of fused salts are generally used. Solvents such as formamide, acetonitrile or ethylene diamine are possible, but their usefulness is limited by the need for sufficiently well-conducting solutions, and other practical difficulties. Beryllium, titanium and zirconium have been obtained by electrolysing ethereal solutions. The pure salts do not conduct in ether, but by using mixtures, e.g. of LiBH4 and the metal chloride or bromide, the necessary conductivity is achieved and good deposits of the metals have been obtained. 

Sakakura studied the electrodeposition of zirconium by chrono-potentiometry. A well-defined one-step chronopotentiogram corresponding to Zr + + 2e Zr was obtained for ZrClg. No interpretation of the chrono-potentiograms of ZrCl4 was attempted. The diffusion coefficients for Zr - " and Zr + were reported. 

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