A surface-treated copper foil including a treating surface, where the root mean square height (Sq) of the treating surface is in a range of 0.20 to 1.50 μm and the texture aspect ratio (Str) of the treating surface is not greater than 0.65. When the surface-treated copper foil is heated at a temperature of 200° C. for 1 hour, the ratio of the integrated intensity of (111) peak to the sum of the integrated intensities of (111) peak, (200) peak, and (220) peak of the treating surface is at least 60%.

A surface-treated copper foil includes a treating surface, and a peak extreme height (Sxp) of the treating surface being in a range of 0.4-2.5 μm, where the hysteresis loop of the surface-treated copper foil includes a first magnetization and a second magnetization when the magnetic field strength of the hysteresis loop is zero, and the absolute difference between the value of the first magnetization and the value of the second magnetization is in a range of 20-1200 emu/m.sup.3.

This cylinder device includes a tubular cylinder that has an opening portion on at least one end side, a metal rod that protrudes through the opening portion of the cylinder, and a sliding contact member that is provided at the opening portion of the cylinder and comes into sliding contact with the rod. A chromium plating film is provided on a surface of the rod. An aspect ratio of an average crystallite diameter in a film thickness direction to an average crystallite diameter in an in-plane direction in the chromium plating film is 0.2 or smaller.

An electrodeposited copper foil includes a bulk copper foil. When a weight of the electrodeposited copper foil is increased to 105.0 wt % during a thermogravimetric analysis (TGA) performed on the electrodeposited copper foil at a heating rate of 5° C./min and an air flow rate of 95 mL/min, a heating temperature of the TGA is defined as T.sub.105.0 wt % and in a range of 550° C. to 750° C.

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.

A method for creating a chrome-plated surface having a matte finish that typically includes: controlling a resistance of a current bridge circuit; depositing a first chromium layer on a substrate positioned in a chromium bath, wherein the first chromium layer is deposited by supplying current from a power source that is electrically connected to the substrate and to anodes positioned in the chromium bath; etching the first chromium layer by engaging a current bridge that closes the current bridge circuit; depositing a first intermediate chromium layer, wherein the first intermediate chromium layer is deposited by supplying current from the power source; etching the first intermediate chromium layer, wherein the first intermediate chromium layer is etched by engaging the current bridge; and depositing a final chromium layer, wherein the final chromium layer is deposited by supplying current from the power source.

A method for creating a chrome-plated surface having a matte finish that typically includes: controlling a resistance of a current bridge circuit; depositing a first chromium layer on a substrate positioned in a chromium bath, wherein the first chromium layer is deposited by supplying current from a power source that is electrically connected to the substrate and to anodes positioned in the chromium bath; etching the first chromium layer by engaging a current bridge that closes the current bridge circuit; depositing a first intermediate chromium layer, wherein the first intermediate chromium layer is deposited by supplying current from the power source; etching the first intermediate chromium layer, wherein the first intermediate chromium layer is etched by engaging the current bridge; and depositing a final chromium layer, wherein the final chromium layer is deposited by supplying current from the power source.

The present invention relates to a very specific electroplating bath for depositing a black chromium layer, a respective method thereof, and a respective substrate with said black chromium layer thereon. The substrate comprising said black chromium layer is excellently suited for decorative purposes.

The present invention relates to a very specific electroplating bath for depositing a black chromium layer, a respective method thereof, and a respective substrate with said black chromium layer thereon. The substrate comprising said black chromium layer is excellently suited for decorative purposes.

The present invention relates to a method for electrodepositing a dark chromium layer on a substrate and a substrate having at least one side fully covered with a dark chromium layer. The method includes utilizing an aqueous trivalent chromium electroplating bath comprising colloidal particles and a step of treating the substrate with a rinse liquid having a temperature of 50° C. or more.