Small Amount Of Gold Research Articles

Superadditive catalysis of homogeneous redox reactions with mixed silver–gold colloids

As silver can be more easily oxidized than gold, certain electrocatalytic reactions occur more rapidly with silver as catalyst than with gold. On the other hand, in the presence of halide and some other anions an autoinhibition of the silver-catalysed reaction takes place because of the formation of an insoluble silver salt at the surface of this metal. This inhibition can be avoided, however, if a small amount of gold was deposited on silver. With electrocatalytic oxidation of N,N-dimethyl-p-phenylenediamine as a model reaction, the advantage of a silver–gold colloid compared with pure silver or gold colloids can be demonstrated.

Surface analysis of gold containing polyimide films

Polyimide films with metallic surfaces were produced by thermal treatment of solutions containing HAuCl4⋅3H2O, hydrogen tetrachloroaurate trihydrate, and either Ciba–Geigy XU 218, poly[5(6)-amino-1-(4′ phenyl)-1,3,3 trimethylindane-3,3′,4,4′-benzophenonetetracarboxylimide] or BTDA-ODA, poly [ p, p′-oxybis (phenylene)-3,3′,4,4′-benzophenonetetracarboxylimide]. Scanning electron microscopy indicated that 0.1-μ particles covered a large portion of the air side surface; whereas, 10-μ particles covered the glass side surface of these films. Auger electron spectroscopy and x-ray photoelectron spectroscopy (XPS) indicated that the particles were gold in the metallic state. Model imide compounds were synthesized and used to evaluate the XPS spectra of both unmodified and gold containing films. Surface analysis data suggested that only a small amount of gold was located within the XPS sampling depth and that the observed gold particles resided underneath a polyimide overlayer. The discrete metal particles had an unexpected influence on the photoelectron spectra of the polyimide and the influence was dependent on particle size. A schematic model of the multilayered modified film surface was developed and the model further probed by electron flood gun and metal vapor deposition studies.

Ultrasonic energy gap measurement in lead doped with a small amount of gold

Ultrasonic energy gap measurement in lead doped with a small amount of gold

Stirred H‐Cell Measurements on Liquid Alloys of Cadmium with a Small Amount of Gold

Stirred H‐cell emf measurements on solvent concentration cells of the type were made with high precision using compositions from 0.001 to 0.021 mole fraction gold at 673°, 742°, and 773°K. Solubility and anodic current efficiency measurements are reported. Plotting techniques are discussed.

Preparation of Unbacked Cadmium Foils of Approximately 50 μg/cm2

A method is given for preparing thin Cd foils by evaporation of Cd on plastic layers and subsequent dissolution of this plastic backing. The difficulty of Cd deposition in vacuum was removed by first evaporating a very small amount of gold in the vacuum apparatus, whereby Cd deposits readily on this gold. A device for dissolving the plastic backlng is described. (D.L.C.)