The Laser-Arc process can be used to produce tetrahedral amorphous carbon (ta-C) coatings, which are particularly suitable for reducing friction and wear on sliding components and tools, especially under abrasive wear conditions. Pure ta-C coatings exhibit high hardness and Young’s modulus due to the high sp3 content, almost approaching the values of diamond. These properties can be tailored by using dopants, such as transition metals and nonmetals. Moreover, the influence of the surface contour affects the properties of such doped and undoped tetrahedral amorphous carbon coatings.
This work focusses on the influence of substrate geometry in the context of gear application and how doping of the coatings under these particular circumstances will have an effect. Specifically, the geometric influences of shading and inclined incident coating plasma, leading to structural changes in the coating as a function of position on the substrate. A brief overview of the changes of coating properties, such as hardness, adhesion, chemical composition and microstructure, is given, as well as a discussion on approaches for the tailoring of selected coating properties. Different analysis methods were used, such as Raman spectroscopy, SEM, scratch testing and hardness measurement to study the structural change and the influence of dopants as well as the geometry.