Influence of carbon chemical bonding on the tribological behavior of sputtered nanocomposite TiBC/a-C coatings

M. D. Abad, J. C. Sánchez-López, M. Brizuela, A. García-Luis, D. V. Shtansky

Producción científica: Artículo en revista indizadaArtículorevisión exhaustiva

36 Citas (Scopus)

Resumen

The tribological performance of nanocomposite coatings containing Ti-B-C phases and amorphous carbon (a-C) are studied. The coatings are deposited by a sputtering process from a sintered TiB2:TiC target and graphite, using pulsed direct current and radio frequency sources. By varying the sputtering power ratio, the amorphous carbon content of the coatings can be tuned, as observed by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The crystalline component consists of very disordered crystals with a mixture of TiB2/TiC or TiBxCy phases. A slight increase in crystalline order is detected with the incorporation of carbon in the coatings that is attributed to the formation of a ternary TiB xCy phase. An estimation of the carbon present in the form of carbide (TiBxCy or TiC) and amorphous (a-C) is performed using fitting analysis of the C 1s XPS peak. The film hardness (22 to 31 GPa) correlates with the fraction of the TiBxCy phase that exists in the coatings. The tribological properties were measured by a pin-on-disk tribometer in ambient conditions, using 6 mm tungsten carbide balls at 1 N. The friction coefficients and the wear rates show similar behavior, exhibiting an optimum when the fraction of C atoms in the amorphous phase is near 50%. This composition enables significant improvement of the friction coefficients and wear rates (μ ∼ 0.1; k < 1 × 10 -6 mm3/Nm), while maintaining a good value of hardness (24.6 GPa). Establishing the correlation between the lubricant properties and the fraction of a-C is very useful for purposes of tailoring the protective character of these nanocomposite coatings to engineering applications.

Idioma originalInglés
Páginas (desde-hasta)5546-5552
Número de páginas7
PublicaciónThin Solid Films
Volumen518
N.º19
DOI
EstadoPublicada - 30 jul 2010
Publicado de forma externa

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