Provided is a piston ring (10) comprising a sliding surface (11) covered with a CrBVN alloy film (3), wherein a B content is within a range of 0.1-1.5 mass % inclusive, a V content is within a range of 0.05-1 mass % inclusive, and a ratio [B content/V content] is within a range greater than 1 and 30 or less, thereby achieving a piston ring (10) having higher wear resistance, cracking resistance, and peeling resistance. This alloy film (3) preferably further includes Ti, the Ti content being within a range greater than 0 mass % and 8 mass % or less. Such a piston ring (10) is preferably mounted on an engine that uses an alcohol fuel or an alcohol-containing fuel.

The present invention provides: a multilayer film structure which has high crystallinity and planarity; and a method for producing this multilayer film structure. This multilayer film structure is provided with: an Si (111) substrate; a first thin film that is arranged on the Si (111) substrate, while being formed of a nitride material and/or aluminum; and a second thin film that is arranged on the first thin film, while being formed of a nitride material. An amorphous layer having a thickness of 0 nm or more but less than 1.0 nm are present on the Si (111) substrate; and the full width at half maximum (FWHM) of a rocking curve of the (0002) plane at the surface of this multilayer film structure is 1.50? or less.

Provided is a surface-coated cutting tool including a base material and a coating including a super-multilayer-structure layer where A layers and B layers different from the A layers in composition are alternately laminated. The super-multilayer-structure layer includes an X area and a Y area those are alternately repeated. In the X area, A layers having a thickness A.sub.X and B layers having a thickness B.sub.X are alternately laminated. In the Y area, A layers having a thickness A.sub.Y and B layers having a thickness B.sub.Y are alternately laminated. The thickness A.sub.X is larger than the thickness A.sub.Y, and the thickness B.sub.X is smaller than the thickness B.sub.Y. Each of the A layers and the B layers comprising one or more elements selected from a group consisting of Ti, Al, Cr, Si, Ta, Nb, and W, and one or more elements selected from a group consisting of C and N.

A coated article includes a substrate, a functional layer over at least a portion of the substrate, and a protective coating over at least a portion of the functional layer, wherein an uppermost layer of the functional layer is a metal oxide layer, and wherein the protective coating comprises a metal nitride layer and a metal oxynitride layer that is disposed between and in contact with at least part of the metal nitride layer and the metal oxide layer of the functional layer.

A method for coating at least one surface of a solid substrate with at least one layer comprising at least one ceramic compound by a suspension plasma spraying (SPS) technique, in which at least one suspension of solid particles of at least one ceramic compound is injected into a plasma jet, and then the thermal jet that contains the solid particle suspension is sprayed onto the surface of the substrate, by way of which the layer comprising at least one ceramic compound is formed on the surface of the substrate; method characterised in that, in the suspension, at least 90 vol % of the solid particles have a larger dimension (referred to as d.sub.90), such as a diameter, smaller than 15 m, preferably smaller than 10 m, and at least 50 vol % of the solid particles have a larger dimension, such as a diameter (referred to as d.sub.50), no smaller than 1 m. A substrate coated with at least one layer that can be obtained by the method. A part comprising the coated substrate and use of the layer in order to protect a solid substrate against degradations caused by contaminants such as CMAS.

A multilayer hard film-coated cutting tool including a cutting tool body and a multilayer hard film formed on a surface of the cutting tool body, wherein the multilayer hard film comprises at least an upper layer and a lower layer; the upper layer is made of a Ti and Si compound layer; the lower layer is made of a multi-layered film of an A-layer and a B-layer, a layer thickness of the B-layer is equal to or thicker than a layer thickness of the A-layer, a ratio of the layer thicknesses of the A-layer and the B-layer being A-layer:B-layer=1:1 to 1:2, the multilayer hard films having 2 to 8 pairs of the A-layer and the B-layer in a case where a single pair is defined by a combination of a single A-layer and a single B-layer.

In the surface-coated cutting tool, a Ti compound layer containing at least nitrogen and carbon is formed on a surface of cutting tool substrate, a nitrogen concentration in the Ti compound layer, in a case of being measured in a direction perpendicular to the surface of the cutting tool substrate in a vicinity of a cutting edge, gradually increases as a distance from cutting tool substrate increases within a range of 0.20 m from the surface of the cutting tool substrate toward the Ti compound layer, an average concentration gradient of the nitrogen concentration is 20 at %/m or more and 300 at %/m or less, and an average nitrogen concentration in the Ti compound layer in the vicinity of the cutting edge is lower than an average nitrogen concentration in the Ti compound layer at a position of a flank face away from the cutting edge by 3 at % or more.

A surface-coated cutting tool includes a substrate and a coating film. The coating film includes an alternate layer. The alternate layer includes a first layer having a first composition and a second layer having a second composition. The alternate layer is formed by alternately stacking at least one first layer and at least one second layer. The first layer and the second layer each have a thickness not smaller than 2 nm and not greater than 100 nm. The first composition is expressed as Ti.sub.aAl.sub.bSi.sub.cN (0.25a0.45, 0.55b0.75, 0c0.1, a+b+c=1). The second composition is expressed as Ti.sub.dAl.sub.eSi.sub.fN (0.35d0.55, 0.45e0.65, 0f0.1, d+e+f=1). The first composition and the second composition satisfy a condition of 0.05da0.2 and 0.05be0.2.

A cutting tool comprising a base material and a coating, wherein the coating comprises a hard particle layer, the hard particle comprises a multilayer structure in which a first unit layer formed from a first compound and a second unit layer from a second compound are alternately stacked, each of the first compound and the second compound consists of one or more metal elements selected from the group consisting of a periodic table group 4 element, a periodic table group 5 element, and a periodic table group 6 element, silicon, and one or more elements selected from the group consisting of carbon, nitrogen, boron, and oxygen, and a percentage of the number of atoms of the silicon to a sum of the numbers of atoms of the metal element and the silicon in the first unit layer is different from that in the second unit layer.

Disclosed is a part including a metal substrate, a non-hydrogenated amorphous ta-C or aC carbon coating that coats the substrate, and an undercoat which is based on chromium (Cr), carbon (C) and silicon (Si) and is disposed between the metal substrate and the amorphous carbon coating and to which the amorphous carbon coating is applied, characterized in that the undercoat included, at its interface with the amorphous carbon coating, a ratio of silicon in atomic percent to chromium in atomic percent (Si/Cr) of 0.35 to 0.60, and a ratio of carbon in atomic percent to silicon in atomic percent (C/Si) of 2.5 to 3.5.