Diamond-like carbon (DLC) can be coated on a variety of substrates including metals (e.g. steel), polymers (e.g. teflon), and ceramics (e.g. glass). The coating provides certain diamond attributes, such as high wear resistance, low frictional coefficient, and extreme chemical inertness. There are different methods that may produce DLC, each with specific characteristics. Fig. 1 shows the classification of DLC types based on the diamond-like bonding (sp3) and graphitic bonding (sp2) for carbon atoms, and also the content of hydrogen atoms.