Abstract: Provided is a piston ring capable of maintaining an excellent effect of preventing aluminum cohesion in a high output engine over a long period of time. At least one of the upper, lower, and side faces of the piston ring is coated with a silica-based coating in which hard nanoparticles are dispersed. The coating has a Martens hardness of 1,000 to 8,000 N/mm2. As the hard nanoparticles, carbon nanoparticles, nanodiamond particles, carbon nanotubes, or carbon nanofibers are used. To the coating, resin particles of a fluorine-based resin or a polyether-based resin may be added.

Abstract: Provided is a piston ring capable of maintaining an excellent effect of preventing aluminum cohesion in a high output engine over a long period of time. At least one of the upper, lower, and side faces of the piston ring is coated with a silica-based coating in which hard nanoparticles are dispersed. The coating has a Martens hardness of 1,000 to 8,000 N/mm2. As the hard nanoparticles, carbon nanoparticles, nanodiamond particles, carbon nanotubes, or carbon nanofibers are used. To the coating, resin particles of a fluorine-based resin or a polyether-based resin may be added.

Abstract: The piston ring of the present invention comprises a thermal spray coating comprising chromium carbide particles having an average particle size of 5 ?m or less, and a matrix metal composed of a Ni—Cr alloy or a Ni—Cr alloy and Ni at least on an outer peripheral surface, said thermal spray coating having an average pore diameter of 10 ?m or less and a porosity of 8% or less by volume. A piston ring having excellent wear resistance, scuffing resistance and peeling resistance with little attackability on a mating member is obtained by forming a homogeneous thermal spray coating having a fine microstructure.

Abstract: A thermal spray coated piston ring having improved initial running-in propery, and having scuffing resistance and wear resistance is provided. The spray coating film (3) of the piston ring (1) contains from 2 to 40 mass % of Sn and from 5 to 50 mass % of graphite, and if necessary, P, Sb, Co, Be, Cr, Mn, Si, Cd, Zn, Fe, Ni and/or Pb, the balance essentially consisting of Cu.

Abstract: The piston ring of the present invention comprises a thermal spray coating comprising chromium carbide particles having an average particle size of 5 ?m or less, and a matrix metal composed of a Ni—Cr alloy or a Ni—Cr alloy and Ni at least on an outer peripheral surface, said thermal spray coating having an average pore diameter of 10 ?m or less and a porosity of 8% or less by volume. A piston ring having excellent wear resistance, scuffing resistance and peeling resistance with little attackability on a mating member is obtained by forming a homogeneous thermal spray coating having a fine microstructure.

Abstract: A thermal spray coated piston ring having improved initial running-in propery, and having scuffing resistance and wear resistance is provided. The spray coating film (3) of the piston ring (1) contains from 2 to 40 mass % of Sn and from 5 to 50 mass % of graphite, and if necessary, P, Sb, Co, Be, Cr, Mn, Si, Cd, Zn, Fe, Ni and/or Pb, the balance essentially consisting of Cu.