Abstract: To provide a piston ring for an internal combustion engine, particularly a second compression ring, which has excellent wear resistance and can achieve both lower fuel consumption and efficient combustion. The above-described problem is solved by a piston ring (1) for an internal combustion engine formed so as to have a tapered shape by a peripheral surface (14) that gradually projects outward from a top to a bottom, and a radial cross-sectional shape of a Napier ring.

Abstract: A substrate is coated with a multi-layer coating, comprising in order: (i) a first functional layer comprising ta-C, (ii) a second functional layer comprising ta-C, (iii) (a) a third functional layer comprising ta-C and a first intermediate layer comprising a carbide of a first element, or (b) a first intermediate layer comprising a carbide of a first element, and a second intermediate layer comprising the first element, wherein the ta-C has a hydrogen content less than 10% and an sp2 content less than 30%; wherein (i) the Young's modulus or (ii) the hardness or (iii) both the Young's modulus and the hardness independently stay the same or increase from layer to layer in (iii) (a) from the first intermediate layer to the first functional layer, or in (iii) (b) from the second intermediate layer to the first functional layer.

Abstract: In a surface of a wire, a first side surface forming an outer circumferential surface in a piston ring includes a tapered surface and a protruding surface, the protruding surface is divided into a first part and a second part by a first virtual surface extending from the tapered surface, and the first part includes a top and is formed in a protruding shape.

Abstract: Provided are a friction reduced and wear resistant coating, a preparation method thereof and a piston ring. The coating includes an adhesive layer, a transition layer, a gradient layer and a function layer in sequence. The gradient layer is a CrMoxN layer in which Mo content progressively increases. The function layer includes at least one cyclical layer. Each cyclical layer includes a first CrMoxN layer and a second CrMoxN layer in sequence from bottom to top. The Mo content of the first CrMoxN layer is lower than the Mo content of the second CrMoxN layer. The coating provided by the present invention has a friction coefficient of 0.3 to 0.45, 10% to 30% lower than a CrN coating, and has an overall hardness of up to 1400 HV to 2600 HV and a thickness of 80 ?m, satisfying the required durability for the full lifecycle of the piston ring. The preparation process of the coating is simple and highly operable, and thus is convenient for industrialization.

Abstract: The invention relates to a metallic work-piece (2, 5, 6, 14, 20, 23) for a hydraulic device (1, 15). The workpiece (2, 5, 6, 14, 20, 23) comprises a coating layer (12), characterized in that the coating layer (12) contains Mo, in particular metallic Mo, with a weight fraction of at least 1%.

Abstract: 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 sp2 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.

Abstract: A coating method for a friction part according to the present disclosure includes the steps of: fabricating a wire comprising, by weight, 0.1% to 1.0% of La2O3 and a balance of Mo; and applying, by flame spraying, the fabricated wire to a surface of the friction part, whereby the friction part has improved wear resistance.

Abstract: A piston ring and a method of manufacturing a piston ring for a piston of a reciprocating internal combustion engine. The piston ring comprises a body having an outer circumferential surface. A tribological coating is formed on the outer circumferential surface of the body. The tribological coating has a dual layer or a triple layer structure and includes a relatively hard base layer and a relatively porous top layer overlying the base layer. The tribological coating may be provided with varying thickness such that its thickness increases gradually from 90° towards 0° in a first radial direction of the piston ring and from 270° towards 360° in a second radial direction of the piston ring reaching its maximum value in the region of 0° and 360°, i.e. the tips of the piston ring.

Abstract: A piston ring and a method of manufacturing a piston ring for a piston of a reciprocating internal combustion engine. The piston ring comprises a body having an outer circumferential surface. A tribological coating is formed on the outer circumferential surface of the body. The tribological coating has a dual layer or a triple layer structure and includes a relatively hard base layer and a relatively porous top layer overlying the base layer. The tribological coating may be provided with varying thickness such that its thickness increases gradually from 90° towards 0° in a first radial direction of the piston ring and from 270° towards 360° in a second radial direction of the piston ring reaching its maximum value in the region of 0° and 360°, i.e. the tips of the piston ring.

Abstract: A piston ring providing improved performance during operation, including reduction in blowby gases and improved oil control, is provided. The piston ring includes an upper layer, a lower layer, and a middle layer each formed from a powder metal material. An exposed sharp first corner is present between an upper ring surface and an upper outer diameter surface, and an exposed sharp second corner is present between a lower ring surface and a lower outer diameter surface. The piston ring also comprises a coating including diamond-like carbon (DLC). The DLC coating is inlaid. Thus, the coating is disposed on the middle layer but is spaced from the upper and lower corners, so that the upper and lower corners of the piston ring are exposed.

Abstract: A piston ring is produced from a main body made of steel or cast steel and comprising a running face, an inner circumferential surface, upper and lower flank regions, and transition regions from the running face to the respective flank region, by coating the running face and the transition regions with a first chromium layer, removing this first chromium layer at the running face down to the base material of the main body, providing at least the running face of the layer-free main body with a nitride layer, and, finally, coating the running face and the transition regions with at least one further chromium layer.

Abstract: A piston ring and a method of manufacturing a piston ring for a piston of a reciprocating internal combustion engine. The piston ring comprises a body having an outer circumferential surface. A tribological coating is formed on the outer circumferential surface of the body. The tribological coating has a dual layer structure and includes a relatively hard base layer and a relatively porous top layer overlying the base layer.

Abstract: The provided sliding member has both excellent wear resistance and excellent coating adhesion even under harsh sliding conditions. The disclosed sliding member (100) is used in the presence of a lubricating oil and includes a base member (10), a metal intermediate layer (12) formed on the sliding surface (10A) side of the base member, a layered carbon coating (18) formed on the metal intermediate layer and having a first carbon coating (14) and a second carbon coating (16) layered alternately therein, and a hard carbon coating (20) formed on the layered carbon coating. Under bright-field observation with a transmission electron microscope, an image of the first carbon coating (14) is brighter than an image of the second carbon coating (16). Furthermore, 10 nm<T2?1000 nm and 0.010?T1/T2?0.60, where T1 and T2 are the thicknesses of the first and second carbon coatings (14, 16).

Abstract: A compression piston ring 2 having a running-surface region 4, an upper flank 6, a lower flank 8 and also an inner circumferential surface 10, wherein the running-surface region 4 is provided with a profiled section, which, as viewed over the axial height of the running-surface region 4, comprises mutually spaced, convexly spherically constructed sections 12, 14 having an upper and lower apex So; Su, wherein a groove 16 with a depth Tn is arranged between the apexes So, Su, wherein both apexes So; Su are arranged below a centre M of the piston ring 2 in the axial direction.

Abstract: A method of forming a piston ring includes providing a base portion formed of a metallic material, the base portion having a first surface, and a second surface that is opposite the first surface, the base portion configured to interface with a piston ring groove. The method includes grinding the first surface to form a reference surface, applying a chromium layer to the second surface, and grinding the chromium layer to reduce a surface roughness of the chromium layer.

Abstract: A piston ring set for internal combustion (IC) engine is provided. The IC engine includes a cylinder having a liner and a finish on the liner. A piston having a crown and a set of grooves is disposed in the cylinder. A set of piston rings is disposed in the set of grooves. The piston rings are disposed in order from closest to the crown and include at least a first compression ring having free ends defining a first end gap, a second compression ring having free ends defining a second end gap. A nominal value of the first end gap of the first compression ring is greater than a nominal value of the second end gap of the second compression ring.

Abstract: A power cylinder assembly for an internal combustion engine is provided. The power cylinder assembly includes a cylinder wall having a channel formed therein and a piston body with a skirt. A piston ring is seated within the channel of the cylinder wall and is sealed against the skirt of the piston body. Specifically, the piston ring has a ring body with an inner face that presents two radially inwardly extending ridges spaced axially from one another by a valley region, and the outer face presents a groove which receives a spring to bias the ridges into sliding engagement with the outer surface of the skirt of the piston body. The ring body also has at least one oil drainage port which extends radially between the valley region of the inner surface and the groove of the outer face for conveying oil from between the ridges into the groove.

Abstract: In a combination oil ring, when a line passing through a center of a segment width is a first intermediate line, a length of a line segment between a position on an engine combustion chamber side and a position on a side distant from the engine combustion chamber on a contour curve at a position at a distance of 3 ?m from an outer peripheral vertex toward an inner peripheral side in a segment radial direction is L, and an intermediate line of the line segment L is a second intermediate line, the second intermediate line is located on the side more distant from the engine combustion chamber than the first intermediate line, and the outer periphery vertex of the segment is located on the second intermediate line or on the side more distant from the engine combustion chamber than the second intermediate line.

Abstract: An oil scraper piston ring and a method for producing it in which a base body is provided with a running surface profile by machining the radially outer circumferential surface thereof, the running surface profile including two running surface lands and an interposed groove, wherein the running surface profile corresponds to that of the finished oil scraper piston ring, and on the groove side, seen in the circumferential direction, drainage holes are introduced into the groove base, at least the running surface lands are provided with a wear-resistant PVD, DLC or TaC layer and, if needed, the wear-resistant layer is subjected to a polishing, honing or lapping operation.

Abstract: Exemplary piston rings are disclosed, comprising a base portion formed of a metallic material, and an outer contact surface extending between opposing side faces of the piston ring. The piston ring may include a coating layer applied to the outer contact surface, with the coating layer including an inner layer and an outer layer. Exemplary methods of making a piston ring are also disclosed, comprising providing a base portion formed of a metallic material, applying an inner layer to an outer surface of the base portion, and applying an outer layer on top of the inner layer.

Abstract: Provided is a wire rod for an I-type oil ring, which includes right and left rail portions and a web portion connecting the rail portions, which has an oil hole or a molten through hole formed in the web portion, and which has a circumscribing circle diameter of 10 mm or less in its transverse contour. The molten through hole has such a remolten portion formed on its exit side as encloses the exit of the molten through hole. The remolten portion exceeds such a molten portion in the transverse section along the center of the molten through hole as is formed in the molten through hole, and is formed to have 200 ?m or less from the outer circumference of the molten through hole and 100 ?m or less in the depth direction of the molten through hole.

Abstract: Provided is a wire rod for an I-type oil ring, which includes right and left rail portions and a web portion connecting the rail portions, which has an oil hole or a molten through hole formed in the web portion, and which has a circumscribing circle diameter of 10 mm or less in its transverse contour. The molten through hole has such a remolten portion formed on its exit side as encloses the exit of the molten through hole. The remolten portion exceeds such a molten portion in the transverse section along the center of the molten through hole as is formed in the molten through hole, and is formed to have 200 ?m or less from the outer circumference of the molten through hole and 100 ?m or less in the depth direction of the molten through hole.

Abstract: There is described an oil control ring idealized for internal combustion engines and formed by a ferrous body less than 2.0 millimeters high, which comprises two external contact surfaces where each surface contains a first and a second end ridges, two slanted faces where each slanted face contains a third end, a peripheral cross section facing the cylinder wall and an internal circular section facing the side of the piston, where each contact surface has a height (h) between the first and the second end ridges of up to 0.15 millimeters and the angle of the slanted face is comprised between 8 and 12 degrees and also by the peripheral cross section is solid, without the presence of cracks, holes and/or other kinds of oil drainage areas. The ring permits an improved distribution of the contact pressure of the combination and, therefore, a better conformability of the ring with the cylinder wall.

Abstract: Provided is a high-toughness coating film having excellent wear resistance, in particular, resistance to cracking and peeling. A high-toughness coating film (2) includes a composition containing a mixture of metallic chromium, in which nitrogen is dissolved, and Cr2N. A content of the nitrogen in the high-toughness coating film is 2.0 to 8.5 mass %, and IP, which is expressed by total of each diffraction peak intensity of Cr2N/(total of each diffraction peak intensity of metallic chromium+total of each diffraction peak intensity of Cr2N), is 3 to 40% when 20 is in a range of 30° to 90°, where ? is an incident angle in X-ray diffraction of the high-toughness coating film.

Abstract: This invention relates to thermal spray coatings, powders useful in deposition of the thermal spray coatings, methods of producing the powders, and uses of the thermal spray coatings, for example, coating of piston rings and cylinder liners of internal combustion engines. The coatings of this invention are applied by thermal spray deposition of a powder. The powder contains bimetallic carbides of chromium and molybdenum dispersed in a matrix metal. The matrix metal contains nickel/chromium/molybdenum.

Abstract: This invention relates to thermal spray coatings, powders useful in deposition of the thermal spray coatings, methods of producing the powders, and uses of the thermal spray coatings, for example, coating of piston rings and cylinder liners of internal combustion engines. The coatings of this invention are applied by thermal spray deposition of a powder. The powder contains bimetallic carbides of chromium and molybdenum dispersed in a matrix metal. The matrix metal contains nickel/chromium/molybdenum.

Abstract: The present invention relates to a wear-resistant layer, which is preferably used on piston rings for internal combustion engines. The wear-resistant layer comprises: 15-25% by weight iron (Fe), 10-25% by weight tungsten carbide (WC), 30-40% by weight chromium (Cr), 10-25% by weight nickel (Ni), 10-25% by weight molybdenum (Mo), 1-10% by weight carbon (C), 0.1-2% by weight silicon (Si), wherein Cr is present in elemental form and/or as a carbide in the form of Cr2C3. A method for applying the wear resistant layer and a piston ring having such a wear resistant layer are also disclosed.

Abstract: Exemplary piston rings are disclosed, comprising a base portion formed of a metallic material, and an outer contact surface extending between opposing side faces of the piston ring. The piston ring may include a coating layer applied to the outer contact surface, with the coating layer including an inner layer and an outer layer. Exemplary methods of making a piston ring are also disclosed, comprising providing a base portion formed of a metallic material, applying an inner layer to an outer surface of the base portion, and applying an outer layer on top of the inner layer.

Abstract: A sliding element in an internal combustion engine has a coating which has the following layers from the outside inwards: a first carbon-based layer, a second carbon-based layer which is harder and/or has a smaller proportion of hydrogen than the first carbon-based layer, a PVD layer and a bonding layer.

Abstract: The second compression ring is formed such that the outer peripheral surface shape has a tapered face, and the radial cross-sectional shape is a rectangular ring, a scraper ring, or a Napier ring, and has a piston ring base and a hard film provided at least on an outer peripheral sliding surface thereof. The piston ring base is composed of a low-alloy steel or carbon steel having a Vickers hardness of Hv 350 Hv 550. The outer peripheral sliding surface is formed so that the axial length is from 0.01 to 0.30 mm between the outer edge end part of the tapered outer peripheral sliding surface and an imaginary line contacting with a lower end surface where a curved surface having a diameter that decreases gradually inward from the outer edge end part toward the lower end in the axial direction is parallel to a ring underside.

Abstract: This invention refers to a piston ring, particularly planned for use in internal combustion engines or compressors, including at least one metallic base (2) to which it is applied, by the physical vapor deposition (PVD) process, a multilayer coating (3) including a periodicity (P), formed by at least one first layer (5) and at least one second layer (5?), being the layers adjacent, bringing one first layer (5) predominantly formed by metallic chromium (5) and one second layer predominantly formed by ceramic chromium (5?).

Abstract: Provided is a piston ring such that it is possible to sufficiently inhibit adhesive wear when the piston ring is mounted to a piston for a diesel engine in which at least the piston ring groove in the piston is formed from steel or cast iron. Disclosed is a piston ring mounted to a piston for a diesel engine, wherein the load length ratio (Rmr2) (in accordance with JIS B0601:2001) of the top surface and bottom surface of the piston ring satisfies each of the following conditions: Rmr2 (0.5%, 0.3[mu]m)=20% and Rmr2 (0.5%, 0.4[mu]m)=40%.

Abstract: The invention relates to a piston ring, having a base body, which comprises a running surface provided with a chamber, an upper and a lower flank surface, and an inner circumferential surface, wherein at least the chamber is provided with at least one wear protection layer, and a PVD cover layer is applied to the running surface at least in some regions such that the base body has the PVD cover layer only in the edge regions, which is to say outside of the chamber, in the finished state.

Abstract: A method for producing piston rings, in particular compression piston rings, in which at least one main element is machined in such a way that a circumferential surface serving as a running surface is provide with a wear-resistant layer of a predeterminable layer thickness, wherein a number of piston ring, in particular compression piston rings, brought together to form an assembly, are machined cylindrically in the region of their circumferential surface, a wear-resistant electrodeposited layer of chrome is applied to the finished machined cylindrical circumferential surface, so that the wear-resistant layer has a constant layer thickness within the assembly as a whole, and subsequently the layer is machined in such a way as to produce a running surface that has a region of maximum layer thickness and at least one region of minimum layer thickness.

Abstract: A piston ring which is provided with a carbon-based coating which has a low friction property and wear resistance, that is, a piston ring which has a carbon-based coating formed over its sliding surface, in which piston ring, the coating is a multilayer coating comprised of two types of layers having different hardnesses laminated in at least two layers, a hardness difference between the two types of layers is 500 to 1700 HV, a high hardness layer has the same or greater thickness than a low hardness layer, and the coating as a whole has a thickness of 5.0 ?m or more. The high hardness layer has a thickness of 5 to 90 nm. The surface on which the coating is formed has a base material roughness of 1.0 ?mRz or less.

Abstract: A piston ring having a base body, which comprises a running surface provided with at least one chamber, an upper and a lower flank surface, and an inner circumferential surface, wherein the running surface is provided with at least one PVD layer such that the same is adjusted to the contour of the running surface without completely filling the chamber, wherein the respective edge region is provided with a layer thickness, b that is reduced compared to the layer thickness, a of the chamber as a function of the configuration of the chamber.

Abstract: A sliding element comprises at least one surface for sliding contact with a running face, wherein a wear layer and a run-in layer made from carbon are applied to the surface, and is characterized in that the run-in layer comprises hydrogen and nanocrystalline carbide phases. In a method for manufacturing a sliding element, the run-in layer is applied by means of a PVD process. A sliding system has an above-described sliding element and a body having a running face. A coating for a sliding element comprises a wear layer which can be applied to the upper side of the sliding element, and a run-in layer which is configured as a carbon layer, and is characterized in that the run-in layer comprises hydrogen and nanocrystalline carbide phases.

Abstract: A sliding member is characterized in that a sliding surface of the sliding member is coated with an amorphous hard carbon film, and a surface of the amorphous hard carbon film has a ten-point mean roughness of equal to or less than 0.7 micrometers and an initial wear height in a range of 0.07 to 0.14 micrometers.

Abstract: A sliding element in an internal combustion engine has a coating which has the following layers from the outside inwards: a first carbon-based layer, a second carbon-based layer which is harder and/or has a smaller proportion of hydrogen than the first carbon-based layer, a PVD layer and a bonding layer.

Abstract: This invention relates to thermal spray coatings, powders useful in deposition of the thermal spray coatings, methods of producing the powders, and uses of the thermal spray coatings, for example, coating of piston rings and cylinder liners of internal combustion engines. The coatings of this invention are applied by thermal spray deposition of a powder. The powder contains bimetallic carbides of chromium and molybdenum dispersed in a matrix metal. The matrix metal contains nickel/chromium/molybdenum.

Abstract: The present invention pertains to wear-resistant components for internal combustion engines, particularly piston rings, especiallly piston rings that feature a wear protection layer with iron base alloy on their surface that is subjected to wear and are characterized in that they are manufactured of a coating powder by means of high-velocity flame spraying (HVOF), wherein the coating is single-phase and comprises the elements Fe, Cr, V and C, and wherein VC forms mixed crystals and also leads to a dispersion strengthening. The present invention furthermore pertains to a method for manufacturing wear-resistant components for internal combustion engines, particularly piston rings, according to the present invention.

Abstract: A piston ring includes a running surface having a running surface profile, and an upper flank surface and a lower flank surface. At least the running surface is provided with a vapor-deposited layer such that part of the running surface is provided with a removable cover enabling an essentially sharp-edged running edge to be formed between the running surface and at least one of the flank surfaces, once the vapor-deposited layer has been produced and the cover has been removed.

Abstract: In order to avoid burn traces on piston rings, it is proposed to provide the piston ring with a wear-protection coating which consists of a material with a thermal conductivity of at least 180 W/(m.K). At least 5% vol. of the wear-protection coating consists of aluminum nitride.

Abstract: The present invention relates to a hard chrome layer, which is formed substantially by electrodeposition from an electrolyte containing a hexavalent chrome and which has fissures in which particles of hard material are intercalated. According to the invention, it is provided that the particles of hard material are formed from cubic boron nitride and have an average particle size of from 0.1 to 1.0 ?m. The present invention also relates to a substrate with such a hard chrome layer and to a tribological system comprising a basic body and an opposing body in the form of such a substrate.

Abstract: Disclosed is a piston ring comprising a supporting material and a wear-resistant coating. The wear-resistant coating is composed of a ternary system A-B—N which is applied using a PVD process and in which A and B each represent an element form the group encompassing Ti, Zr, Hf, V, Nb, Ta, Cr, Mo W, Al, Si and C, wherein A ?B and N represents nitrogen. The thickness of the wear-resistant coating amounts to ?3 ?m.

Abstract: The present invention relates to a piston ring with improved running-in and wear behaviour as well as to a method for the production thereof. According to a first embodiment, the piston ring comprises a ring body (2), an adhesive promoter layer (4) of a Ni-alloy applied to the bearing surface of the ring body (2) by thermal spraying, a wear-resistant coating (6) of a Mo-alloy with CrC, WC, MoC applied to the adhesive promoter layer (4) by thermal spraying; and a running-in layer (8) of an AlCu-alloy or Ni-graphite-alloy applied to the wear-resistant coating (6) by thermal spraying. According to a second embodiment, the piston ring comprises a ring body, an adhesion layer applied to the bearing surface of the ring body, and a running-in layer, comprising nickel graphite, that is applied to the adhesion layer.

Abstract: A piston ring, having a base body, which comprises a substantially circumferential running surface, which has an upper and a lower flank surface, an inner circumferential surface, and a butt opening provided with defined butt clearance, wherein the transition of the running surface butt edge into the respective butt surface is configured as a sharp edge, and the running surface is provide with at least one PVD cover layer ?10 ?m at least up to the respective running surface butt edge.

Abstract: A piston ring, with a main body, which exhibits a contact surface, an upper and a lower side surface, and an inner circumferential surface, in which at least one of the side surfaces is provided at least with one PVD coating layer, to the effect that the layer thickness of the PVD coating layer tapers radially from the outside inward.

Abstract: A piston ring (22) is covered at least partially with a layered structure (30). The layered structure (30) comprises: —a first intermediate layer (32) comprising at least one element of group IVB, group VB or group VIB; —a second intermediate layer (34) deposited on top of the first intermediate layer (32) and comprising a diamond-like nanocomposite composition; —a diamond-like carbon layer (36) deposited on top of the second intermediate layer (34).

Abstract: A piston ring for an internal combustion engine is made of steel and has an outer contact surface that is nitrated and coated to no more than 70 ?m with a protective coating comprising nitrides of aluminum and/or silicium and/or zirconium in a matrix of chromium-nitride based material.