Accession Number : ADA182102

Title :   Voltage Fluctuations at Sodium Beta Alumina/Mercury Electrodes.

Descriptive Note : Technical rept. Jan-Jun 87,

Corporate Author : UTAH UNIV SALT LAKE CITY DEPT OF PHYSICS

Personal Author(s) : Kuo,Chu K ; Brophy,James J

PDF Url : ADA182102

Report Date : Jun 1987

Pagination or Media Count : 15

Abstract : Voltage fluctuations at mercury sodium Beta alumina ceramic electrode interfaces have been investigated. Noise voltages in the absence of current can be explained by Nyquist and interfacial chemical reaction noise. The activation energy of the reaction noise rate constant is determined to be 0.29 eV, which suggests that diffusion of the sodium ions in the electrolyte dominates the reaction. In the presence of a decomposition current, the low frequency noise varies. After current flow, the noise voltage decays and can be observed for some tens of hours. Both current and post current noise signals suggest conductivity fluctuations arising form diffusion of the mobile sodium ions. Fitting experimental data to the diffusion and decay equations yields a diffusion constant of .000008 sq cm per second and a characteristic length equal to the bulk sample length. Keywords: Diffusion noise, Conductivity fluctuations, Superionic conductors, Beta alumina ceramics and single crystals.

Descriptors :   *ALUMINUM OXIDES, *CERAMIC MATERIALS, *ELECTRODES, ACTIVATION ENERGY, CONDUCTIVITY, VARIATIONS, DECAY, EQUATIONS, YIELD, DIFFUSION, NOISE, CHEMICAL REACTIONS, INTERFACES, IONS, MOBILE, SODIUM, DECOMPOSITION, ELECTROLYTES, LOW FREQUENCY, SIGNALS, SINGLE CRYSTALS

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE