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An approach to the mechanism of Corrosion of tungsten in alkaline solutions
Author(s) -
Ammar I. A.,
Darwish S.,
Khalil M. W.
Publication year - 1982
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.19820130503
Subject(s) - tafel equation , dissolution , chemistry , corrosion , hydroxide , tungsten , inorganic chemistry , stoichiometry , anode , electrochemistry , electrode , organic chemistry
The mechanism of anodic dissolution and hence of corrosion of W in alkaline solutions (NaOH, Na 3 PO 4 ) has been investigated by measuring anodic Tafel lines by the galvanostatic technique, and calculating both the Tafel slope b and the effect of pH on anode potential as diagnostic criteria for the mechanism. The quasi‐equilibrium principle of Kabanov , Burstein and Frumkin for all reactions preceding the rate‐determining (rd) step has been used to calculate the concentration of intermediates as a function of potential. Two mechanisms have been tested with this principle:(i) the first involving the formation and dissolution of nonstoichiometric and stoichiometric surface oxides, and (ii) the second deals with the formation and dissolution of hydroxide species.