ISSN:
1572-8838
Keywords:
chemical diffusion coefficient
;
conductivity relaxation method
;
electrical conductivity
;
NiAl2O4
;
van der Pauw four-point method
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Electrical Engineering, Measurement and Control Technology
Notes:
Abstract NiAl2O4 spinel was formed by solid state reaction. Its electrical conductivity was measured in the temperature range of 680–940 °C and under various oxygen-rich environments, as well as under reducing conditions. From the temperature dependence of the conductivity, the activation energies for conduction increase for decreasing oxygen partial pressures. From the partial oxygen pressure dependence, the defect structure of the material was analysed. The conductivity change with respect to P O2 can be attributed to singly and doubly ionized nickel vacancies. The chemical diffusivity of the oxide was determined by conductivity relaxation upon abrupt change in P O2 in the surrounding atmosphere. The oxygen chemical diffusion coefficient is of the order of magnitude of 10−4 cm2 s−1.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1026585124816
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