Nanoindentation Study of Superhard Tisin, Diamond-Like Carbon (Dlc), and Tisin/DLC Hybrid Coatings on Tungsten Carbide Cutting Tools

Abstract

The nanoindentation technique has emerged as a powerful method for precisely assessing the mechanical properties of materials such as hardness and modulus at the nanoscale. This paper elaborates the capabilities of nanoindentation to determine the intrinsic mechanical properties, particularly hardness and elastic modulus of advanced coatings TiSiN, DLC, and a novel TiSiN/DLC hybrid coating on tungsten carbide cutting tools. X-ray diffraction (XRD) analysis revealed unique peak orientations for each coating, with TiSiN and TiSiN/DLC hybrid coatings exhibiting a coating texture with preferred (111) and ( 200) orientations in achieving superior hardness. Raman analysis confirmed the DLC nature of the coatings. Calotest measurements demonstrated differences in coating thickness, with DLC being thinner than TiSiN and TiSiN/DLC coatings. Nanoindentation tests revealed that the TiSiN coatings displayed exceptional superhardness, with a hardness of 40.2 GPa and an elastic modulus of 405.2 GPa, whereas the TiSiN/DLC hybrid coatings showed notable improvements in hardness and elastic modulus compared with the DLC coatings, with a hardness of 32.2 GPa and an elastic modulus of 356.8 GPa. These findings underscore the mechanical strength of TiSiN coatings, making them suitable for the machining industry. The TiSiN/DLC hybrid coatings exhibit potential for various industrial applications. This research enhances our understanding of superhard coatings, contributing to surface engineering and the development of high-performance coatings.