A sliding member includes a carbon transfer layer and can superiorly effectively decrease friction and reduce wear. A method produces the sliding member. The sliding member includes a substrate and a carbon transfer layer. The carbon transfer layer is disposed on the surface of the substrate and includes both sp.sup.2 bonded carbon and sp.sup.3 bonded carbon. The carbon transfer layer preferably has a ratio sp.sup.3/(sp.sup.2+sp.sup.3) of the sp.sup.3 bonded carbon to the totality of the sp.sup.2 bonded carbon and the sp.sup.3 bonded carbon of 0.1 or more.

A piston ring for an internal-combustion engine may include a body having a substantially annular external surface and a physical vapor deposition coating layer disposed on the external surface. The body may include a gap defined between a first end and a second end. The piston ring may also include a first half in a region of the gap and a second half opposite the first half. The coating layer of the first half may have a thickness gradient, and the coating layer may define a greater thickness in a vicinity of the first end and the second end and a reduced thickness in regions further away from the vicinity of the first end and the second end. The coating layer of the second half may have a uniform thickness.

A piston ring for an internal-combustion engine may include a body having a substantially annular external surface and a physical vapor deposition coating layer disposed on the external surface. The body may include a gap defined between a first end and a second end. The piston ring may also include a first half in a region of the gap and a second half opposite the first half. The coating layer of the first half may have a thickness gradient, and the coating layer may define a greater thickness in a vicinity of the first end and the second end and a reduced thickness in regions further away from the vicinity of the first end and the second end. The coating layer of the second half may have a uniform thickness.

Fluoropolymer compositions are described which comprise tetrafluoroethene polymers and substantially spherical particles. Further provided are methods of making such compositions and articles prepared from such compositions. The compositions can be used to increase the wear resistance and/or the electrical insulation properties of an article.

Fluoropolymer compositions are described which comprise tetrafluoroethene polymers and substantially spherical particles. Further provided are methods of making such compositions and articles prepared from such compositions. The compositions can be used to increase the wear resistance and/or the electrical insulation properties of an article.

A piston ring includes a body portion presenting a running surface, and a spring member disposed between the body portion and a ring groove of a piston. A running surface of the piston ring presents an upper rail, a lower rail, and a fulcrum disposed between the rails and each extending radially outwardly. An outermost tip of the fulcrum is disposed radially outwardly relative to an outermost surface of the rails, and the running surface presents a convex shape along the fulcrum. The fulcrum contacts an oil film applied to a cylinder wall as the piston reciprocates along the cylinder wall. The spring member presses the body portion of the piston ring toward the cylinder wall and causes the body portion to pivot about the fulcrum to provide for improved control of the oil film, less friction, and reduced oil consumption.

A piston ring includes a body portion presenting a running surface, and a spring member disposed between the body portion and a ring groove of a piston. A running surface of the piston ring presents an upper rail, a lower rail, and a fulcrum disposed between the rails and each extending radially outwardly. An outermost tip of the fulcrum is disposed radially outwardly relative to an outermost surface of the rails, and the running surface presents a convex shape along the fulcrum. The fulcrum contacts an oil film applied to a cylinder wall as the piston reciprocates along the cylinder wall. The spring member presses the body portion of the piston ring toward the cylinder wall and causes the body portion to pivot about the fulcrum to provide for improved control of the oil film, less friction, and reduced oil consumption.

A piston seal assembly for a gas turbine engine includes a seal composed of a nickel-based superalloy; a component in contact with the seal and defining a seal-counterface; and a coating on the seal at the seal-counterface, wherein the coating is a metal alloy binder phase and a hard particle phase distributed through the binder phase.

A piston seal assembly for a gas turbine engine includes a seal composed of a nickel-based superalloy; a component in contact with the seal and defining a seal-counterface; and a coating on the seal at the seal-counterface, wherein the coating is a metal alloy binder phase and a hard particle phase distributed through the binder phase.

The present invention addresses the problem of providing a piston ring covered with a DLC coating that has excellent wear resistance and shows a low attacking property on a cylinder bore sliding surface. The problem is solved by a piston ring which is used in the presence of an engine lubricating oil and includes a DLC coating on an outer peripheral sliding surface. The DLC coating has an sp.sup.2 component ratio of 0.5 to 0.85 as determined from a TEM-EELS spectrum obtained by a combination of a transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS), as well as a coating hardness of 12 GPa to 26 GPa and a Young's modulus of 250 GPa or less as measured by a nanoindentation method.