A tin alloy electroplating bath, wherein the tin alloy electroplating bath includes (A) a soluble tin salt, (B) a soluble nickel salt and/or a soluble cobalt salt, (C) an oxycarboxylic acid or a salt thereof, (D) a nitrogen-containing heterocyclic unsaturated compound, and (E) a surfactant, and the pH of the tin alloy electroplating bath is 3 to 7.

A silver-plated product is produced by forming a surface layer of silver on a base material by electroplating at a liquid temperature of 10 to 35° C. and a current density of 3 to 15 A/dm.sup.2 in a silver plating solution so as to satisfy (32.6x−300)≤y≤(32.6x+200) assuming that a product of a concentration of potassium cyanide in the silver plating solution and a current density is y (g.Math.A/L.Math.dm.sup.2) and that a liquid temperature of the silver plating solution is x (° C.), the silver plating solution containing 80 to 110 g/L of silver, 70 to 160 g/L of potassium cyanide and 55 to 70 mg/L of selenium.

A method is provided for creating a porous coating on a surface of a substrate by electrodeposition. The substrate is a part of the cathode. An anode is also provided. A coating is deposited or disposed on the surface by applying a voltage that creates a plurality of porous structures on the surface to be coated. Continuing to apply a voltage creates additional porosity and causes portions of the attached porous structures to detach. A covering layer is created by applying a voltage that creates a thin layer that covers the attached porous structures and the detached portions which binds the porous structures and detached portions together.

A nickel-coated copper foil suitable for mass production, to which YAG laser welding can be applied while reducing the electrical resistivity by forming a nickel plating layer with a thickness of 0.5 μm or less on a surface of a copper foil by Ni plating, is provided. The nickel-coated copper foil has an overall thickness of 200 μm or less, and includes a copper layer made of Cu or a Cu alloy, and a nickel plating layer made of Ni or a Ni alloy, covering a surface of the copper foil, having a thickness of 0.01 μm or more and 0.5 μm or less, and including a surface having an a* value of 0 or more and 10 or less and a b* value of 0 or more and 14 or less in an L*a*b* color system obtained by an SCI measurement method in accordance with JIS Z 8722.

A surface treated copper foil 1 includes a copper foil 2, and a first surface treatment layer 3 formed on one surface of the copper foil 2. The first surface treatment layer 3 of the surface treated copper foil 1 has a Ni concentration of 0.1 to 15.0 atm % based on the total amount of elements of C, N, O, Zn, Cr, Ni, Co, Si, and Cu, in an XPS depth profile obtained by performing sputtering at a sputtering rate of 2.5 nm/min (in terms of SiO.sub.2) for 1 minute. A copper clad laminate 10 includes the surface treated copper foil 1 and an insulating substrate 11 adhered to the first surface treatment layer 3 of the surface treated copper foil 1.

An electrolyte and a method to electroplate a metal on a substrate using the electrolyte are described. The electrolyte includes an imidazolium compound, a metal salt, and water. The imidazolium compound has formula (I) ##STR00001##
wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, and R.sup.5 are each independently selected from an H atom and an organic radical. L.sup.− is a compatible anion. The metal salt can include but is not limited to salts of the metals Li, Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, Bi, La, Ce, Al, Ag, Au, Ga, V, In, Nb, Mo, and W.

Described is a cathodic treatment for the electrodeposition of a metal layer securely adherent to the surface of stainless steel objects in an electrolytic bath comprising one or more metals belonging exclusively to the groups from 3 to 12 of the periodic table, excluding the elements nickel, cobalt, cadmium, ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, gold and rhenium, and methanesulfonic acid with a concentration of between 100 and 400 g/l.

An object of the invention is also a process for applying a metal layer securely adherent to the surface of stainless steel objects, comprising a cathodic treatment as described above.

Moreover, the invention further relates to an object comprising stainless steel equipped with a covering obtained by means of a process of the type described.

The invention relates to an optical element including a resin body having a functional surface covered with a reflective coating capable of reflecting light beams, the reflective coating including a copper layer covering at least the functional surface, a nickel layer covering the copper layer, and a chromium layer covering the nickel 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.

An electroplated article includes a base member that includes one or more base member-metallic elements; and an electroplated layer that is formed directly on the base member. The electroplated layer includes at least a first electroplated layer-metallic element and a second electroplated layer-metallic element that is different from the first electroplated layer-metallic element. The second electroplated layer-metallic element is a metallic element that is identical to at least one of the one or more base member-metallic elements. A ratio of the second electroplated layer-metallic element in the electroplated layer is continuously decreased as being away from the base member in the thickness direction of the electroplated layer. Alloy grains including at least the first and second electroplated layer-metallic elements are distributed in the electroplated layer such that a clear interface is not formed between the base member and the electroplated layer.