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

Abstract

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 Ti2O3, and TiO2 oxides and very resistant Ta2O5 and ZrO2 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 (Na3PO4 and K3PO4 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.

Electrochemical corrosion behavior of Ti‐10V‐2Fe‐3Al in different corrosive media

“…Although, most of them are studied in physiological solution, few studies are carried out in sea water, acid, and other solutions. The corrosion behavior of most Ti alloys in physiological solution is generally similar . Spontaneous passivation of these alloys in simulated body fluid is noted for most of these alloys.…”

“…Titanium is generally resistant to corrosion attack in the oxidizing acidic media, but passivated titanium exhibits poor corrosion resistance in reducing environment such as hydrochloride and sulfuric acids . Spontaneous formation of passive titanium dioxide (TiO 2 ) film, typically few nanometer thick, is responsible for their corrosion performance and its biocompatibility in various aggressive and body fluids solutions …”

“…Over the last decade, an impressive amount of literatures on corrosion of Ti alloys are documented . Although, most of them are studied in physiological solution, few studies are carried out in sea water, acid, and other solutions.…”

Correlation of corrosion resistance of dental alloy restorations with oral lichen planus pathology

“…These casting alloys can be precious alloys or non‐precious alloys such as cobalt–chromium alloys or nickel–chromium alloys and copper alloys (Table ) . More recently Ti and new Ti alloys have been investigated to be used in oral cavity as well . Although dental alloys have been used in dentistry for over a century and currently there is a variety of dental alloys available on the market, they suffer biodegradation processes resulting in some cases in atypical responses of the host .…”