A study of the supercooling behavior of high purity liquid bismuth

<p>"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.</p> <p>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.</p> <p>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.</p>

Name thesis:degree_name

Ph. D. in Nuclear Engineering

Grantor

University of Missouri at Rolla

Year dc:date.available

2016

Author dc:creator

• Bramfitt, B. L.

• Nuclear Engineering

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/449

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-1451