On the evaluation of corrosion resistances of amorphous chromium carbide thin-films
2014 (English)In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 0019-4686, Vol. 122, no SI, 224-233 p.Article in journal (Refereed) Published
The possibilities of evaluating the corrosion resistance of amorphous chromium carbide (Cr-C) films containing nanometre-sized carbide grains embedded in an amorphous carbon matrix on the basis of polarization curves, voltammograms and the oxidation charge have been studied for Cr-C films with different carbon concentrations. The films, which were manufactured by non-reactive directcurrent magnetron sputtering, were studied in 1.0 mM H2SO4 at both 22 °C and 80 °C, and with scanning electron microscopy and X-ray photoelectron spectroscopy prior to and after the electrochemical experiments. It is demonstrated that the oxidation of these Cr-C films gives rise to a surface composed of Cr2O3 and partially oxidized carbon and that the non-corroding oxidation current due to the carbon oxidation increases with increasing carbon concentration in the films as well as with the electrolyte temperature. Since the oxidation current is composed of contributions from both Cr-C and carbon oxidation it is not straightforward to evaluate the corrosion resistances of these films based on the current in the passive region, the mixed potential (i.e., the corrosion potential) or the open circuit potential. The present results in fact indicate that Cr-C films with high carbon concentrations may have better corrosion resistances than the corresponding films with lower carbon concentrations although larger currents in the passive region can be seen in polarization curves.
Place, publisher, year, edition, pages
2014. Vol. 122, no SI, 224-233 p.
chromium carbide, corrosion
Research subject Chemistry with specialization in Inorganic Chemistry
IdentifiersURN: urn:nbn:se:uu:diva-212777DOI: 10.1016/j.electacta.2013.11.130ISI: 000334007900029OAI: oai:DiVA.org:uu-212777DiVA: diva2:679215
FunderSwedish Foundation for Strategic Research