On the defect diffusivity in Co9−xS8

Defect mobility in non-stoichiometric cobaltous sulphide, Co9−xS8, has been studied as a function of temperature (873–1073 K) and sulphur activity (10−4–10−1 Pa) using microthermogravimetric re-equilibration technique. Chemical diffusion coefficient calculated from oxidation and reduction runs were...

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Bibliographic Details
Published inSolid state ionics Vol. 141-142; pp. 295 - 299
Main Author Grzesik, Z
Format Journal Article
LanguageEnglish
Published Elsevier B.V 01.05.2001
Subjects
Chemical compounds
Chemical diffusion
Co9S8
Microthermogravimetry
Re-equilibration kinetics
Chemical diffusion
Microthermogravimetry
Chemical compounds
Re-equilibration kinetics
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Summary:Defect mobility in non-stoichiometric cobaltous sulphide, Co9−xS8, has been studied as a function of temperature (873–1073 K) and sulphur activity (10−4–10−1 Pa) using microthermogravimetric re-equilibration technique. Chemical diffusion coefficient calculated from oxidation and reduction runs were virtually the same, clearly indicating that the rate determining step of the overall re-equilibration process is the solid state diffusion. It has been found that the chemical diffusion coefficient does not depend on sulphur activity and thereby on defect concentration and can be described as a function of temperature by the following empirical equation: D̃=3.1·10−2 exp((−76 kJ/mol)/RT).
ISSN:0167-2738
1872-7689
DOI:10.1016/S0167-2738(01)00764-0