Studies of micromorphology and current efficiency of zinc electrodeposited from flowing chloride electrolytes

Thesis/Dissertation · Thu May 01 00:00:00 EDT 1986

DOI:https://doi.org/10.2172/5351255· OSTI ID:5351255

Mc Vay, Laura ^[1]; Muller, Rolf H. ^[1]; Tobias, Charles W. ^[1]

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1. Univ. of California, Berkeley, CA (United States)

Results of a study of the micromorphology and current efficiency of zinc electrodeposited from flowing, acidic chloride solutions are reported. The effects of six variables were examined: flow rate, current density, zinc and hydrogen ion concentration, concentrations of nickel, iron and cadmium impurity ions, and the nature of the substrate. The development of micromorphology was studied in-situ by means of videomicrography and ex-situ by means of scanning electron microscopy. This investigation focused on the formation of grooved deposits, which are found under a wide range of deposition conditions. The major conclusions of this study are: the most important variable determining whether grooved deposits form is the interfacial concentration; large protrusions orient themselves parallel to the flow direction with the orientation starting upstream and progressing downstream; large protrusions become ridges due to growth of the highest current density portions of the electrode under mass transport control. The current efficiency was measured using EDTA titration and weight measurements. The fraction of the current taken by zinc deposition increased with zinc concentration, ranging up to 100%, and decreased with pH. The efficiency of zinc deposition was affected by the flow rate and the substrate employed. Impurities lowered the current efficiency.

• Research Organization: Univ. of California, Berkeley, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5351255
• Report Number(s): LBL-21492; ON: DE87000059
• Resource Relation: Other Information: Thesis. Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ZINC
ELECTRODEPOSITION
CHLORIDES
EFFICIENCY
ELECTRIC CURRENTS
SOLUTIONS
CHLORINE COMPOUNDS
CURRENTS
DEPOSITION
DISPERSIONS
ELECTROLYSIS
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
LYSIS
METALS
MIXTURES
SURFACE COATING
360101* - Metals & Alloys- Preparation & Fabrication
400400 - Electrochemistry