Doping and Alloying Effects on DLC Coatings

Doped or alloyed diamond-like carbon (DLC) coatings is an important category of DLC characterized by the incorporation of different elements in their struc-ture to achieve multifunctionality and improved properties in respect to pure DLC films. By controlling the nature, content and distribution of the dopants, tailored synthesis of doped-DLC with properties adapted to a desired value for specific applications can be obtained. Common dopants are light elements (B, Si, N, O or F), metals and combinations thereof to modify properties such as hardness, tribological properties, internal stress, adhesion, electrical conductivity or biocompatibility. The purpose of this chapter is to provide an overview of the different alloyed-DLC and more novel nanostructured coatings reported in the literature in relation with the property of interest. The tribological properties will be discussed in light of their chemical composition and microstructure trying to obtain general trends or correlation between them when possible due to the high number of parameters influencing their practical tribological response.