Doctoral Dissertations

Abstract

"Zinc (Zn) powders form the anode of a modern alkaline battery. During discharge of the battery, zinc oxidizes to produce zinc oxide and electrons. Alkaline batteries are prone to leakage during storage. This phenomenon is caused by zinc dissolving into the alkaline solution and producing hydrogen gas as a byproduct. In the past, mercury was alloyed with zinc to slow down the corrosive process and prevent excessive hydrogen generation. Since mercury has been deemed as a health and environmental hazard, bismuth and indium are now used as alloying elements to suppress hydrogen evolution. Although alloying elements have been successfully incorporated in zinc powders, the problem with hydrogen evolution in alkaline batteries still persists. A comprehensive study to characterize zinc powders alloyed with bismuth and indium was conducted to determine the chemical, structural, and physical properties that influence hydrogen gassing in alkaline batteries.

Differences between low and high gassing powders may be attributed to chemistry, surface roughness, powder morphology, size, powder surface area, and phases present in the zinc powders. Structural studies on zinc powders were conducted using electron backscatter diffraction (EBSD), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The results may be the first structural characterization reported for the zinc powders. Powders that passed and failed gassing tests were also compared to detect physical and chemical differences. Multiple factors influence the hydrogen generation properties of zinc powders, and certain factors may be desirable in an alkaline battery. The most desirable appear to be a BiIn₂ phase at the zinc grain boundaries and powder surfaces and characteristics which exhibit low surface area such as smooth surfaces and regular, rounded shapes"--Abstract, page iv.

Advisor(s)

OKeefe, Matt

Committee Member(s)

Robertson, D. G. C.
Miller, F. Scott, 1956-
Dogan, Fatih
O'Keefe, T. J. (Thomas J.)

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Metallurgical Engineering

Sponsor(s)

Big River Zinc Corporation
National Science Foundation (U.S.). Integrative Graduate Education & Research Traineeship

Publisher

University of Missouri--Rolla

Publication Date

Summer 2005

Journal article titles appearing in thesis/dissertation

  • Phase identification of zinc alloy powders using electron backscatter diffraction
  • Chemical analysis of air atomized Zn powders
  • Morphological analysis of air atomized Zn alloy powders
  • Influence of cooling rate on the microstructure and chemical composition in cast zinc alloys

Pagination

xvi, 158 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2005 Martin Gerardo Perez, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Subject Headings

AtomizationPowder metallurgyStorage batteries -- MaterialsZinc powder

Thesis Number

T 8720

Print OCLC #

775360711

Electronic OCLC #

905906320

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