Experimental study of mechanical properties and scratch resistance of ultra-thin diamond-like-carbon (DLC) coatings deposited on glass

To improve the mechanical and tribological properties of glass, an ultra-thin diamond-like-carbon (DLC) coating of 2.2 nm thick was deposited on the surface of glass, using the linear ion beam deposition technique. The coated glass showed significant improvement in scratch resistance against severe damage, such as cracking, delamination, and chipping. To understand the mechanism, an experimental study was carried out. It was found that the major contribution to the significantly improved scratch resistance attributable to the compressive stress, which was yielded during the deposition process and resides in the coating, as well as the top layer of glass substrate.

Research highlights► Experimental studies of the improved scratching resistance of a 2.2 nm thick DLC coating on glass. ► A Nano-Indenter XP with a conical-shaped tip was used to carry out the scratching tests. ► AFM was used to take images of the scratches and examine and analyze the damage morphologies. ► The improved scratch resistance is due to the compressive stress stored in the top layer of surface. ► The stress yielded in deposition counteracts the tensile stress of scratching, reducing damages.