In the thesis, four DLC coatings were selected: two hydrogen free DLC coatings (GCr and GCrSi) and two hydrogenated DLC coatings (DCr and DCrSi), which are the two main groups in the DLC family. Three annealing conditions (argon annealing, air annealing and HIPping/high pressure argon annealing) were designed to evaluate the stability and performance of the four DLC coatings. The microstructure of the DLC coatings was characterised by Raman spectrum, GIXRD, SEM/Due-beam SEM, EDX and TEM. Scratch tests were performed to assess the adhesion of the coatings. Both the mechanical and tribological properties of the DLC coatings were evaluated including nanohardness, coefficient of friction and wear factor. The influence of high pressure and oxidation was discussed, and the comparison of four different coatings was made.