DLC thin films have been deposited using a combined DC and high power impulse vacuum-arc process. Hardness and adhesion of the obtained films deposited at different substrate temperature were studied using nanohardness testing and the scratch tester REVETEST (R). The bonding structure of as-deposited films was analyzed by Raman scattering and X-ray photoelectron spectroscopy. The results show that the substrate temperature is one of the main parameters influencing the sp(3)-to-sp(2) ratio of carbon atom bonds in the coatings, which in turn affects the films mechanical properties. XRD analysis shows that a CrxCy interfacial layer forms at 280 degrees C. which reduces the adhesion properties of the DLC coatings. High quality DLC coatings are obtained by control of the specimen temperature below 280 degrees C using a sensor that is in direct contact with the substrate.