The effect of high electronic current density on the motion of Au[superscript 195] and Sb[superscript 125] in gold

"The effect of high electronic current density on the motion of -the Au195 and Sb125 ion.s in gold was ,studied by means of a novel lathe-sectioning technique that per~itted the assay of radioactive sections from a specim,en only ""3 mm. in diameter. The mobility, v/j, of the Au195 ion in gold was investigated in the temperature range 814 to l016°C, with a corresponding variation in mobility of from 906 x lO-13cm3/sec/A to 7.3 x 10-12 cm3/sec/A, and was found, within experimental uncertaihty, to obey the Nernst-Einstein relation, v/j = e*pD/kT. The effective charge, e*, was determined to be independent of temperature, with the value (9 ± l)e, indicating that.. the momentum exchange with the conduction electrons dominates the force arising from the direct interaction between the external electric field and the positively charged ion. The specific resistivity of the gold ion-vacancy complex was calculated to be (1.2 ± Oe3)~Q cm/%,defect, using the mOdels of either Huntington and Grone or Piks. Allbaugh the. activation energy for the·· self ... diffusion of gold obtaitied fr,omthe slope of the In v/j vs. :l,/T plot I . •. . .' . agrees with those of Huntington and Gfone and. Kuzmenko, within the uncertainty of the' experimental data, the mobilities reported by Kuzmeriko arie a factor of four higher, and those of , Huntington and Grone a factor of four lower, than those ob~ tained in the present experiment. The uncompensated lattice distortion in the vicinity of,the surface markers, and the non-isothermal nature of the measurement of the motion of the . , markers in. the Huntington and Grone experiment, and the PQssible error in the temperature measurement and/or the diffusion zone dimensions for couples broken open before sectioning, in the Kuzmenko exper'iment, are possible systematic errors in the previous experiments which might account for the observed differences. In addition, the method of temperature measurement, by means of a gold self-diffusion coefficient temperature scale, led to extremely accurate measurement of this parameter in the present experiment. The electromigration of the Sb125 ion in gold was studied at atemperatur,e of 853°C, for which the mobility was ,9.24 x 10 -11 cm 3/ sec/A, and at l009°C, corr' espond1.ng' to a mobility of 4.54 x 10 .... 10 cm3/se~/A& Altho~ghonly two different temperatures were investigated, bhere were sufficient data to estimate an effective charge and specific resistivity of the activated ~omplex of (140 ± 40)e and (18,.:!:. 6), !-LO cm/% defect, respec~ivelYG As the shift of the ~125 "" Sb tracer was some ~O% greater than the mean square diffusional penetration distance of the antimony, and the mobility of the antimony ion some one to twp orders of magnitude greater than that of the solvent gold atoms"" it appears that ,electromigration techniques could 'be adapted as a practical method for purifying metals,,'as an addition to, or substitute for zone refinemente"

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Gilder, Howard Michael

Contributors dc:contributor

• Lazarus, David

• electronic current density
• lathe-sectioning technique
• radioactivity
• gold
• ion mobility

Statement dc:rights

• 1965 Howard Michael Gilder

Language dc:language

en

Identifier

6196988

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/23973