Crack Resistance of Diamond‐Like Carbon Coatings

The aim of the current paper is the study of the crack resistance of diamond‐like carbon (DCL) coatings deposited by direct current magnetron sputtering (dcMS) and high‐power pulse magnetron sputtering (HPPMS) with different process parameters. For this purpose nanoindentation with a very high force resolution of RFN ≤ 1 nN was used to analyze different a‐C coatings, which were deposited under variation of the process gases argon, helium and neon. Owing to significantly high force resolution of the indenter, a large number N = 31,872 of data points in each force‐displacement curve was recorded, which enabled the desired analyses. Based on the results, it can be stated that the nanoindentation is able to provide knowledge on the crack formation of DLC coatings. The coatings deposited with neon show a more promising behavior in point of elastic‐plastic properties. In addition, the evaluation of the force‐displacement curves indicates a higher resistance to crack formation of these coatings. Furthermore, investigations on the influence of the process gas pressure were conducted using Ne and three pressures p = 2.0 Pa, p = 1.5 Pa and p = 1.0 Pa. The results show that applying the moderate gas pressure can generate coatings with the highest toughness compared to the coatings deposited with higher and lower gas pressures.