Progress report - ESR 11: Abqaat Naseer

date: May 17, 2022

category: News

New self-lubricating, anti-wear, corrosion-resistant coatings for reducing lubricant consumption in mechanical parts

Initially developed in the late 90s, a-C:H:Si:O, conveniently also known as diamond-like nanocomposite, is one of the most industrially acclaimed carbon-based coating material. Owing to a combination of low-friction, anti-sticking, and oxidation resistance, its applications cover a wide range of sectors; from aerospace to the food industry. While, it is widely accepted that interpenetrating a-C:H and Si:O networks are responsible for the improved protective nature of these coatings, the individual and synergistic role of dopants (Si, O, H) on structure and properties is not very well understood. With the aim to develop an understanding of the relationship between coating composition, structure, and properties; this study explores the role of increasing Si, O, and H doping in the amorphous carbon matrix. The individual and admixed effect of dopants on hardness, reduced modulus, surface energy, and thermal stability of coatings is investigated. To summarize our findings, Si doping results in increased hardness, and surface energy. The role of O is mainly influenced by the Si content, and therefore with an increasing O/Si ratio a decrement in mechanical and thermal performance is observed. On the other hand, H doping leads to improved mechanical and tribological performance of the coatings. The evolution in coating properties with respect to the possible formation of a-C:H/Si:O networks and Si-C linkages is studied. Thereby, while exploring the effect of doping on properties of a-C:H:Si:O coatings, suitable coating stoichiometry for achieving desired application performance as solid lubricants, is being developed.