Abstract
The purpose of this paper is to characterise the anodic oxide films formed on titanium and two ternary titanium alloys, Ti-15Mo-5Al and Ti-10Mo-10Al in 1%, 10% and 20% hydrochloric acid solutions at 25, 50, and 75°C. The anodic film on titanium in hydrochloric acid is stable between + 0.6 V (SCE) and + 2.0 V (SCE). For our new ternary titanium alloys, the passive film is formed at about + 0.6 V (SCE) and is stable to + 2.0 V (SCE). The anodic polarization curves for alloys differ from the base metal curve, presenting two peaks for the critical passivation current density in the active-passive potential range. At the first current peak (the first critical passivation potential E cr1 ) a porous titanium pentaoxide (Ti 3 O 5 ) is formed. When the potential reaches the second current peak (the second critical passivation potential E cr2 ) the compact and protective titanium dioxide (TiO 2 ) is formed. The impedance spectra exhibit the typical behaviour for a passive film i.e. a near capacitive response illustrated by a phase angle close to - 90 over a wide frequency range. The oxide film on titanium and its alloys in hydrochloric acid solutions exhibits a high resistance and a low capacitance (with the increase of the potential) attributed to the surface roughness decrease as the oxide layer thickens.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.