Premium
Diffusion of Alkali Ions in Vitreous Silica
Author(s) -
ROTHMAN S.J.,
MARCUSO T.L.M.,
NOWICKI L.J.,
BALDO P.M.,
McCORMICK A. W.
Publication year - 1982
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1982.tb10786.x
Subject(s) - alkali metal , ionic radius , diffusion , arrhenius equation , analytical chemistry (journal) , ion , chemistry , impurity , silicate , activation energy , inorganic chemistry , thermodynamics , physics , organic chemistry , chromatography
The diffusion of Cs + , Rb + , and K + ions was measured in three grades of vitreous SiO 2 by the radiotracer‐sectioning technique or Rutherford, backscattering spectroscopy. The values of the diffusion coefficient, D , at 1000°C decrease strongly with increasing ionic radius, changing by about two and one‐half orders of magnitude per row of the periodic table. The difference between D Cs and D Rb is largely in the preexponential factor D o in the Arrhenius expression rather than in the activation enthalpy Q . The values of D are much smaller than the tracer D values for the alkali metal ion in homogeneous Rb or Cs silicate glasses. Residual metallic impurities in the SiO 2 decrease both Q and D o for the diffusion of Rb. The results are analyzed in terms of the interstitial structure of vitreous SiO 2 .