US Patent 7634963 Piston ring comprising a coated running surface, and coating agent

The invention relates to a piston ring whose running surface is provided with a coating containing a plastic material. Said piston ring is characterized in that the coating is composed of at least one polyamide-imide and/or at least one polyether ether ketone with embedded particles which can be embodied as hard material particles, solid lubricant particles, or metallic particles. The invention further relates to a piston/piston ring arrangement comprising at least one inventive piston ring and an agent for coating at least the running surface of the piston ring.