Deposition of hard highly transparent abrasion-resistant DLC on glass

摘要

The interest towards Diamond-Like Carbon (DLC) coatings has increased in recent years, due to its high-performance properties, which include low friction, high hardness, resistance to abrasion and an excellent transparency. One of the main substrate of interest is glass. Currently DLC deposition on glass relies on Plasma-Assisted Chemical Vapour Deposition (PACVD) methods equipped with ion guns, since non-electrically conductive substrates have difficulty in achieving good hard carbon coating deposition with high adhesion strength by any other method. These ion sources require very frequent maintenance. The Physical Vapour Deposition (PVD) of sp3 hybridised carbon via magnetron sputtering of carbon targets presents clear advantages in terms of process cleanliness in comparison with PACVD methods, but it also comes with inherent challenges. In particular, an enhancement of the substrate-plasma interaction, namely in the level of ion bombardment during deposition, needs to be ensured. In magnetron sputtering, approximately 5% of the gaseous species are ionised, thus several methods are used to increase ionic availability. In this paper the authors address new methodologies for hard abrasion-resistance DLC deposited on glass. These methods have been demonstrated in different deposition systems from R&D to industrial scale, for applications from small to large area touch screens, smart displays and ultimately large architectural glass, sectors where highly transparent scratch resistance coatings are required.