Doctoral Dissertations

Abstract

"This investigation involves a study of the supercooling behavior of pure bismuth as affected by the melting atmosphere, the amount of superheat, and the intentional addition of metallic and non-metallic foreign materials to the melt. It was found that the amount of oxide on the melt surface is a controlling factor in the degree of supercooling obtainable in bismuth. In the presence of a thick bismuth oxide surface layer the amount of superheat below a 15°C drastically decreases the amount of supercooling due to the retention of nuclei in the surface film that promote nucleation upon cooling of the melt.

Of the 40 foreign materials intentionally added to the bismuth melt only 9 altered its supercooling behavior. These materials, in order of decreasing effectiveness in reducing the supercooling, were antimony, tellurium, selenium, indium, cadmium, lead, copper, silver and gold.

A drastic reduction in supercooling resulted by the addition of small concentrations (less than about 10 ppm) of antimony and tellurium whereas the other elements had a moderate to slight effect. Since all of these elements completely dissolved in the melt, a mechanism was proposed whereby the elements are concentrated on the melt surface, either in elemental or oxide form, as a monolayer of atoms. This monolayer can act as a site for heterogeneous nucleation depending upon its crystallographic relationship to the (111) of bismuth. The experimental evidence presented in the investigation lends support to the disregistry theory proposed by Turnbull and Vonnegut"--Abstract, pages i-ii.

Advisor(s)

Leighly, Hollis P., 1923-2004

Department(s)

Nuclear Engineering and Radiation Science

Degree Name

Ph. D. in Nuclear Engineering

Sponsor(s)

Texaco Company

Publisher

University of Missouri at Rolla

Publication Date

1966

Pagination

xiii, 143 pages, 5 transparencies

Note about bibliography

Includes bibliographical references (pages 124-127).

Rights

© 1966 Bruce Livingston Bramfitt, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Bismuth -- Heat treatment
Supercooling

Thesis Number

T 1911

Print OCLC #

5977867

Electronic OCLC #

902862383

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