Gold films dissolution

Inhibitors form a film on the surface that blocks the dissolution of the substrate. Adsorption of an alkyl-thiol to the surface of the CU3AU alloy resulted in an inaeased surface tension of the gold film this is observed as an increase in the value of <., which depresses dissolution of copper. This behavior resembles inhibition of copper corrosion on a pure copper surface where benzotriazole increases the potential to start significant copper dissolution this was demonstrated by Cruickshank et using in situ AFM. However, when the critical potential for benzotriazole film... 

In recent years, increasing attention has been paid to human exposure to mercury via dental amalgams (Skare 1995). Exposure results from elemental mercury vapor released from amalgams that is either inhaled directly or swallowed after dissolution in saliva. A Jerome 511 Gold Film Mercury Vapor Analyzer (Arizona Instrument Corp., Jerome, AZ) has been used to measure mercury vapor released from amalgam during routine dental procedures (Engle et al. 1992) or at other times to establish baseline... 

Not only nanometric structures such as tubes or particles are important but also the application of nanoporous materials such as the case of nanoporous gold films [48, 87] (NPG) that could be prepared by selective dissolution of silver form Au/Ag alloys under free corrosion conditions. In this case, stability of the electrode can be increased and biomolecule immobilization could happen inside the mnable pores. Due to their well-defined nanopores, anodized alumina membranes have found many applications, among them, impedimetric immunosensing [63]. 

Figure 25 depicts the kinetic DD dependence for dissolution of a 100 A thick gold film deposited onto the surface of a 0,3 cm silicon plate. Thiekness of the gold film was estimated by independent methods. The DD dependence for this film was plotted by 18 points, which corresponds on the average (for a period between two measurements) to a 5.5 A thickness of the dissolved gold layer. 

Duncan and Frankenthal report on the effect of pH on the corrosion rate of gold in sulphate solutions in terms of the polarization curves. It was found that the rate of anodic dissolution is independent of pH in such solutions and that the rate controlling mechanism for anodic film formation and oxygen evolution are the same. For the open circuit behaviour of ferric oxide films on a gold substrate in sodium chloride solutions containing low iron concentration it is found that the film oxide is readily transformed to a lower oxidation state with a Fe /Fe ratio corresponding to that of magnetite . 

Flade potential, 247 Flame-annealed gold surfaces and the work of Kolb, 81 Flat band potential, 483 Fluctuations asymmetrical and unstable systems, 255 controlling progress in pitting, 299 in pitting dissolution, 251 and corrosion processes, 217 during dissolution, 252 at electrodes, theory, 281 during film breakdown, 233 and mathematical expressions thereof, 276... 

FIG. 26. Scanning electron micrographs (A) the template-synthesized gold tubule ensemble obtained after dissolution of the polyester template membrane (B) as per A, but after CVD synthesis of TiSj outer tubes on the Au inner tubes. These tubular microstructures contained 0.86 mg of TiS2 cm of substrate A1 surface area (C) as per B, but with a larger quantity (2.04 mg cm ) of TiSj (D) CVD TiSj film. 

Film electrodes have been essential components of quartz microbalance studies of stoichiometry of many electrodeposition and dissolution experiments as well as polymer electrode characterization [25]. In the quartz microbalance, changes in mass are detected by measurement of changes in the resonant frequency of a quartz crystal oscillator as the mass adhering to the surface changes. The oscillation is feasible because thin-film metal electrodes (typically gold) applied to opposing faces of a piezoelectric quartz crystal serve both to induce the oscillation and to provide a site for electrochemical reaction. 

The oxide redox energy levels for all elements except gold are cathodic to the redox level of the H2O/O2 couple. Gold, however, is an impractical component for compound semiconductors. All other compound semiconductors employed as electrolysis photoanodes will undergo surface oxidation in aqueous electrolytes to produce a surface oxide film which normally constitutes the stable surface of the photoelectrode. Our proposed mechanism indicates that the proton induced oxide dissolution reaction arises from product ir ion interactions with the oxide anion (0=). 

The high aspect ratio gold nanorods were not eaten from the ends by cyanide, as were their spheroidal counterparts. The topology and chemical potential of edge atoms of spheroids may not favor the formation of stable films of protective AuCN. This may be the reason for enhanced reactivity and anisotropic dissolution of spheroids. 

Cu—Au alloys Chen and coworkers studied Cu dissolution from gold-rich, disordered AU3CU films with 111 surfaces in 0.6 M NaCl 4- 0.01 M HCI by EC-STM. In... 

Li et al. produced polyaniline [PANl] nanowires by electropolymerization in the pores of a 22 nm thick PS-Z -P2VP nanoporous film on a gold substrate. Growth nucleated only in the pores created after selective dissolution of the minority P2VP chains in ethanol. Nanowires with diameters of 30-40 nm continued to grow out of the template where they entangled to form a highly porous film. 

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