Published online by Cambridge University Press: 15 February 2011
The aim of this work is to investigate the long term (3000 exposure hours) tendency of passive layers on titanium to breakdown in Tani-Zucchi and Carter-Brugirard artificial saliva undoped and doped with chloride and fluoride ions. The non-uniformity of the saliva pH (from 7.88 to 5.73 and extreme case 2.15) was simulated. The following techniques were used: potentiostatic, potentiodynamic and linear polarization, the monitoring of the open circuit potentials vs. exposure time and atomic force microscopy. The breakdown (pitting) potential at about +2.9 V and the re-passivation potential at +2.4 V in Tani-Zucchi artificial saliva were determined. So, the pitting protection potential is very noble and can not be reached in human body.