Impact of carbon content on the phase structure and mechanical properties of TiBCN coatings via direct current magnetron sputtering

In this study, unbalanced direct current magnetron sputtering was employed to develop TiBCN coatings on Si (100) wafers. The carbon (C) concentration was varied to manipulate the phase structure and mechanical properties of the coatings. The coatings were analyzed using Raman spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and nanoindentation. The results revealed that the TiBCN-2 coating, with a C concentration of 4.4 at.%, exhibited optimal hardness and elastic modulus values of 33 and 291 GPa, respectively. On the other hand, as the C content increased from 4.4 to 24.4 at.%, the hardness and elastic modulus values of the coatings decreased to 21 and 225 GPa, respectively, due to the formation of boron nitride and carbon phases within the coating matrix. Therefore, the inclusion of an ideal C concentration can considerably improve the properties of TiBCN coatings, thus rendering the coating a desirable material for cutting tools.