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Corrosion behaviour of Ti–Ta–Sn alloy systems in 0.9% NaCl solution
Author(s) -
Khan W. Q.,
Deen K. M.,
Ghauri K. M.,
Ahmad R.,
Tabish T.,
Atiq S.,
Zaigham H.,
Ali L.
Publication year - 2012
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201206523
Subject(s) - materials science , dielectric spectroscopy , corrosion , oxide , alloy , tantalum , electrochemistry , tin , bilayer , grain boundary , open circuit voltage , chemical engineering , metallurgy , microstructure , analytical chemistry (journal) , membrane , chemistry , electrode , physics , quantum mechanics , voltage , engineering , chromatography , biochemistry
Two alloys of varying contents of tantalum (Ta) and tin (Sn) were prepared and homogenized to evaluate their microstructural and electrochemical characteristics. The microstructural features were revealed through optical microscopy and X‐ray diffraction methods. The formation and stability of passive film was studied by open circuit potential, potentiodynamic polarization and electrochemical scratch tests. The electrochemical impedance spectroscopy results simulated with equivalent electrical circuit suggested bilayer structure of outer porous and inner barrier oxide films. The quantitative data showed thick inner barrier oxide film retarded electrochemical reactions at low ‘Ta’ and ‘Sn’ concentration. The increased percentage of ‘Ta’ and ‘Sn’ deteriorated barrier properties by agglomeration of Ta 2 Sn 3 and Ta 0.15 Ti 0.85 precipitates within grains and at the grain boundaries.