A manufacturing method of a home appliance including a hairline according to disclosed embodiment includes forming at least one plating layer on the base material, processing the transverse hairline on the upper surface of the plating layer by tilting the hairline processing wheel at a predetermined angle, and forming a coating layer on the hairline.

A terminal material for a connector provided with a base material in which at least a surface layer is made of copper or copper alloy, a nickel-plating layer made of nickel or nickel alloy and formed on a surface of the base material, a silver-nickel alloy plating layer made of silver-nickel alloy and formed on at least a part of the nickel-plating layer, and a silver-plating layer made of silver and formed on the silver-nickel alloy plating layer; the silver-nickel alloy plating layer has a film thickness 0.05 .Math.m or more and less than 0.50 .Math.m and a nickel content 0.03 at% or more and 1.00 at% or less.

A Ni-plated steel sheet according to an aspect of the present invention includes: a base steel sheet; an Fe—Ni diffusion alloy region disposed on the base steel sheet; and a Ni plating region disposed on the Fe—Ni diffusion alloy region, in which an average equivalent circle diameter of crystal grains made of Ni (fcc) in the Ni plating region measured in a cross section perpendicular to a rolled surface of the base steel sheet is 0.2 to 4.0 μm.

A Ni-plated steel sheet according to an aspect of the present invention includes: a base steel sheet; an Fe—Ni diffusion alloy region disposed on the base steel sheet; and a Ni plating region disposed on the Fe—Ni diffusion alloy region, in which an average equivalent circle diameter of crystal grains made of Ni (fcc) in the Ni plating region measured in a cross section perpendicular to a rolled surface of the base steel sheet is 0.2 to 4.0 μm.

A method for plating a work piece includes forming a work piece, where the work piece includes first and second segments that are electrically isolated. The first segment is connected in a first circuit and the second segment is connected in a second circuit. The first circuit may include a first power source and the second circuit may include a second power source. The work piece and the first and second segments may be disposed in a common solution, and current may be applied in the first circuit and the second circuit to create first and second metal surfaces. The first and second metal surfaces may be made from the same base metal. The first and second metal surfaces may be created simultaneously, with the work piece and the first and second segments disposed in a common solution.

A method for plating a work piece includes forming a work piece, where the work piece includes first and second segments that are electrically isolated. The first segment is connected in a first circuit and the second segment is connected in a second circuit. The first circuit may include a first power source and the second circuit may include a second power source. The work piece and the first and second segments may be disposed in a common solution, and current may be applied in the first circuit and the second circuit to create first and second metal surfaces. The first and second metal surfaces may be made from the same base metal. The first and second metal surfaces may be created simultaneously, with the work piece and the first and second segments disposed in a common solution.

A piston ring includes a base body having an inner circumferential surface, first and second flank surfaces and an outer circumferential surface, wherein a first hard chromium layer with a crack network is applied to the outer circumferential surface and has a crack density of 10-250 cracks per mm and solid particles having an average particle size of 0.01-10 μm embedded in cracks of the first hard chromium layer, a second hard chromium layer having a crack network applied to the first hard chromium layer and having a crack density of the crack network of 10-250 cracks per mm, no solid particles being embedded in the cracks thereof, where the cracks have an average width of 1-15 μm, the cracks are electrolytically expanded and the surface proportion of the cracks are 3-25% based on a total surface of the second hard chromium layer.

An object comprising a chromium-based coating on a substrate is disclosed. The chromium is electroplated from an aqueous electroplating bath comprising trivalent chromium cations, wherein the chromium-based coating comprises: a first chromium-containing layer, on the substrate, having a thickness of at least 100 nm, and a Vickers microhardness value of 700-1000 HV; a second chromium-containing layer, on the first chromium-containing layer, having a Vickers microhardness value that is at least 1.3 times higher than the Vickers microhardness value of the first chromium-containing layer, and a crystal size of 8-35 nm; and wherein the chromium-based coating exhibits a critical scratch load value (L.sub.c2) of at least 60 N in the adhesion test according to ASTM C1624-05 (2015; point 11.11.4.4), and wherein the chromium-based coating does not contain chromium carbide. Further is disclosed a method for its production.

An object comprising a chromium-based coating on a substrate is disclosed. The chromium is electroplated from an aqueous electroplating bath comprising trivalent chromium cations, wherein the chromium-based coating comprises: a first chromium-containing layer, on the substrate, having a thickness of at least 100 nm, and a Vickers microhardness value of 700-1000 HV; a second chromium-containing layer, on the first chromium-containing layer, having a Vickers microhardness value that is at least 1.3 times higher than the Vickers microhardness value of the first chromium-containing layer, and a crystal size of 8-35 nm; and wherein the chromium-based coating exhibits a critical scratch load value (L.sub.c2) of at least 60 N in the adhesion test according to ASTM C1624-05 (2015; point 11.11.4.4), and wherein the chromium-based coating does not contain chromium carbide. Further is disclosed a method for its production.

The present invention is directed to provide novel composite copper components. For example, provided is a composite copper component including a copper oxide-containing layer formed on at least a portion of the surface of a copper component, in which when the surface of the composite copper component is bonded to a resin substrate by thermocompression, and the copper component is peeled off from the resin substrate after the thermocompression bonding, metal contained in the copper oxide-containing layer is transferred to the resin substrate.