a-C:Ag coatings (1.2–23.4 at.% of Ag) were deposited using magnetron sputtering. Ag nanoparticles appear embedded in the carbon matrix or segregated to the column boundaries or surface. The silver doping has not promoted significant changes of the sp2/sp3 ratio although a decrease of the hardness is observed (from 17 to 7 GPa). The tribological behavior did not show a clear dependence on the silver concentration in unlubricated or lubricated conditions (fetal bovinum serum) against alumina or UHMWPE balls. Ag nanoparticle dispersion enhanced the bactericide behavior as determined by the released Ag+ ion in the fluid media. There is no clear effect of friction rubbing on the released silver indicating that diffusion and top segregation are prevalent mechanisms for its dissolution.

European Regional Development Funds program (EU-FEDER), Leverhulme International Network Grant (CARBTRIB), Spanish Ministry of Economy, Industry and Competitiveness (projects n° MAT2015-65539-P and MAT2015-69035-REDC), Junta de Andalucía (project P10-TEP 06782) and CSIC (201560E013) are acknowledged for financial support.

Peer reviewed