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On the determination of Oxide Formation Rate for tantalum in chromate bath from cell voltage
Author(s) -
Ammar I. A.,
El Kasimi R.
Publication year - 1981
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.19810120303
Subject(s) - tantalum , current density , oxide , voltage , cell voltage , anode , electrode , chemistry , analytical chemistry (journal) , electric field , materials science , current (fluid) , thermodynamics , inorganic chemistry , metallurgy , electrical engineering , physics , engineering , chromatography , quantum mechanics
Anodic oxide growth has been followed on Ta in chromate solutions by measuring the cell voltage/time relations at current densities between 200 and 700 m̈A/cm 2 . It is demonstrated here that the reference electrode can be dispensed with for technical studies, and estimates for the parameters of oxide growth can be calculated from cell voltage/time relations. Results are given for the formation rate, electric field strength, reciprocal capacity and increase of oxide thickness. The formation rate has been found to depend on current density following the empirical relation previously established for valve metals from the results of anodic charging curves. The empirical constants calculated here agree with the values in the literature, thus showing that cell voltage measurements can be used successfully to estimate growth parameters.