Premium
Characterisation of passive film and corrosion behaviour of a new Ti‐Ta‐Zr alloy in artificial oral media: In time influence of pH and fluoride ion content
Author(s) -
Vasilescu C.,
Drob S. I.,
Osiceanu P.,
CalderonMoreno J. M.,
Drob P.,
Vasilescu E.
Publication year - 2015
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.201408025
Subject(s) - materials science , alloy , microstructure , corrosion , x ray photoelectron spectroscopy , dielectric spectroscopy , fluoride , scanning electron microscope , chemical engineering , metallurgy , layer (electronics) , composite material , electrochemistry , inorganic chemistry , chemistry , electrode , engineering
The new Ti‐15Ta‐5Zr alloy revealed a homogeneous bi‐phase α + β microstructure without inclusions or secondary phases. The alloy native passive film contains both Ti 2 O 3 , and TiO 2 oxides and very resistant Ta 2 O 5 and ZrO 2 oxides (X‐ray photoelectron spectroscopy). All main electrochemical and corrosion parameters in artificial Carter‐Brugirard saliva had more favourable values than those of Ti and other implant alloys, due to the Ta and Zr alloying elements, which contributed with their protective oxides to the native passive film and due to the alloy very homogeneous microstructure. Impedance spectra indicated a passive film formed by two layers: an inner, insulating, barrier layer that provides the high corrosion resistance and an outer, porous, less protective layer that permits the absorption of ions and species from surrounding environment into its pores, favouring both interaction and bioactivity. X‐ray photoelectron spectroscopy and scanning electron microscopy detected new depositions (Na 3 PO 4 and K 3 PO 4 protective compounds) of 5 nm thickness on the alloy surface after 1000 h in Carter‐Brugirard saliva, which confer to the substrate both corrosion resistance and bioactivity.