Abstract: PURPOSE: To study the effect of carbon-silica composite films on corrosion resistance of Co-Cr alloy in simulated oral environment and provide evidences for clinical application of this new material. METHODS: Co-Cr alloy specimens were cut into appropriate size of 20 mm × 20 mm × 0.5 mm. Then, the carbon-silica composite films were spin-coated onto the specimens. Subsequently, ICP-AES was used to observe the Co, Cr, Mo ion concentrations. Finally, Tafel polarization curves of the specimens were used to measure the electrochemical corrosion resistance by electrochemical workstation. SAS8.0 software package was used for statistical analysis. RESULTS: The results of ICP-AES showed that the ion concentrations of Co, Cr, Mo of specimens coated with composite films in the testing liquid were significantly smaller than that of Co-Cr alloy specimens. Tafel polarization curves showed that in the specimens coated with composite films, the corrosion potential moved in the positive direction and increased from -0.261 V to -0.13 V. At the same time, the corrosion current density decreased from -5.0017μA/cm² to -5.3006 μA/cm². CONCLUSIONS: Carbon-silica composite films (silica=61.71wt %) can reduce the release of metal ions significantly and improve the corrosion resistance of Co-Cr alloys effectively. Carbon-silica composite films may be a promising dental material.

Key words: Carbon-silicon composite, Co-Cr alloy, Polarization curves, Corrosion resistance