A review on the tribology of carbon coatings on rubber

Rubber is widely used as a crucial sealing material in the aerospace, petrochemical, and automotive industries to prevent contaminants from entering enclosures and lubricants from leaking. However, severe wear and friction occur during sliding motion, which are major causes of seal failure and significantly impact the safety and service life of equipment. To increase the wear resistance of rubber surfaces, diamond-like carbon (DLC) coatings have been extensively studied because of their low friction coefficient, high hardness, excellent wear resistance, and chemical inertness. The hardness, elasticity, and adhesion of the coating can be effectively controlled by adjusting the deposition parameters. This allows the film to accommodate the deformation of the soft rubber substrate, preventing delamination while avoiding thermal degradation or damage to the rubber. Additionally, the chemical composition of carbon-based films, which primarily consist of carbon and hydrogen, is compatible with rubber, ensuring strong interfacial adhesion. In this paper, research progress on the tribological properties of carbon-based films for rubber surface modification over the past two decades is reviewed. In contrast to previous reviews that focused primarily on the general applications and fundamental properties of DLC coatings, this work delves into the distinctive advantages of DLC coatings on rubber surfaces under various deposition conditions. This work explores the underlying mechanisms for friction reduction and wear resistance enhancement while also identifying critical research gaps and proposing future directions for the field.