Surface-enhanced Raman spectroelectrochemical studies of corrosion films on implant Co–Cr–Mo alloy in biosimulating solutions
✍ Scribed by Ying-Sing Li; Kang Wang; Peixin He; Bill X. Huang; Paul Kovacs
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 196 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0377-0486
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✦ Synopsis
Surface-enhanced Raman (SER) spectroelectrochemical studies were carried out to identify the surface species formed on Co-Cr-Mo alloy under di †erent conditions. The surface Ðlms identiÐed for the alloy in air include chromium(III) oxide, molybdate, molybdenum(VI) oxide and possibly cobalt(II) oxide. The air-formed molybdenum species disappear quickly in 0.15 M NaCl. In 0.15 M NaCl, part of the CoO and might react with Cr 2 O 3 water to form and respectively. It is difficult to reduce these lower oxidation state oxides and Co(OH) 2 Cr(OH) 3 , hydroxides of Cr and Co. At high potentials, species remain at the interfaces. From electrochemical Co(OH)
2 data, it appears that the alloy passivates very well, especially in artiÐcial saliva. At lower potential, the Cr species play major roles in the passivation of the alloy, and at higher potential the Co species take on these roles. The dissolution rates of Mo from the Co-Cr-Mo alloy in NaCl and NaOH solutions are too low to be measured, indicating that the passive Ðlms of Cr and/or Co protect further oxidation of underlying Mo in the alloy.