A comprehensive review of tribological performance of coatings on automotive piston rings

Friction and wear significantly influence automotive engine performance and efficiency, leading to substantial fuel power loss across various engine components. Among these, the frictional losses between the piston ring and cylinder liner assembly contribute notably to overall inefficiencies. To address this issue, thin-film coating techniques have emerged as a promising solution for enhancing the mechanical and tribological properties of engine components. This paper reviews various wear-resistant, corrosion-resistant, and antifriction coatings, including carbon-based coatings, nitride coatings, carbide coatings, oxide coatings, and composite coatings formed by intermixing different coating materials or layering them in multilayer structures. The effects of altering the elemental composition of these coatings are also discussed. Additionally, the synergistic impact of combining surface texturing with coatings on piston rings is explored. Finally, recent advancements and potential future directions for coating technologies in automotive applications are highlighted.