The present invention discloses a de-bouncing keypad and a preparation method thereof, wherein the keypad is composed of a rubber substrate and a metal contact having three layers of layered structures. A layer of tin alloy or lead alloy is plated on a surface of the metal contact by electroplating or chemical plating. The metal contact plated with the tin alloy or lead alloy has excellent contact bouncing resistance and arc-ablation resistance, and the metal contact is further composited with the rubber to shape and prepare the rubber de-bouncing keypad.

A gold-plating etching process for 5G high-frequency signal boards is carried out according to the following steps: the outer dry film, the plug gold-plating, the film removing, and the alkaline etching. The alkaline etching solution comprises 100 to 150 g/L of cupric chloride, 90 to 120 g/L of ammonium chloride, and ammonia. The pH value is 9.6 to 9.8. The ratio of the ammonia and the alkaline etching solution is (550-800):1000. The present invention provides a gold-plating etching process of 5G high-frequency signal boards. The alkaline etching procedure is performed right after gold-plating, eliminating the outer etching process after gold-plating. Costs of the outer film pressing, the exposure, and the development can be saved. The flow rate is improved. Requirements of 5G communication circuit boards are satisfied. That is, the transmission speed of 5G communication high-frequency signal boards of the present invention is fast.

A gold-plating etching process for 5G high-frequency signal boards is carried out according to the following steps: the outer dry film, the plug gold-plating, the film removing, and the alkaline etching. The alkaline etching solution comprises 100 to 150 g/L of cupric chloride, 90 to 120 g/L of ammonium chloride, and ammonia. The pH value is 9.6 to 9.8. The ratio of the ammonia and the alkaline etching solution is (550-800):1000. The present invention provides a gold-plating etching process of 5G high-frequency signal boards. The alkaline etching procedure is performed right after gold-plating, eliminating the outer etching process after gold-plating. Costs of the outer film pressing, the exposure, and the development can be saved. The flow rate is improved. Requirements of 5G communication circuit boards are satisfied. That is, the transmission speed of 5G communication high-frequency signal boards of the present invention is fast.

A metal article comprises an alloy substrate having a surface and a non-diffused metal monolayer disposed thereon. The surface has a first surface work function value .sub.s. The non-diffused monolayer deposited on the surface has a second surface work function value .sub.s that is less negative than the first surface work function value. A method for depositing the monolayer via underpotential deposition (UPD) is also disclosed.

A metal article comprises an alloy substrate having a surface and a non-diffused metal monolayer disposed thereon. The surface has a first surface work function value .sub.s. The non-diffused monolayer deposited on the surface has a second surface work function value .sub.s that is less negative than the first surface work function value. A method for depositing the monolayer via underpotential deposition (UPD) is also disclosed.

A method for depositing an aluminizing coating onto a substrate. The method includes: (a) depositing a layer, containing platinum and at least 35% of nickel, onto a surface of the substrate; and (b) depositing an aluminum coating onto the layer.

The present invention relates to a method for producing an electrode for alkaline electrolysis based on a composition of metal sulfides on a Ni foam substrate. The metal can be Mo, Ni, Co, Fe and/or W. In a first step S1), there is performed a metal deposition, e.g. by electroplating, the metal, Me1/Me2, being Mo, Ni, Co, Fe, and/or W, on a Ni foam substrate resulting in a metal-Ni compound being formed on and/or in the Ni foam substrate. In a second step, S2) there is performed a sulfiding on the metal-Ni compound from the first step S1). The third step S3) is an optional repetition of S1 and/or S2 at least one time. The step S1) and step S2) thereby result in the formation of electrocatalytic active nano-sites with Me1-Me2-SNi compounds. It is found that these nano-sites are capable of reducing the so-called overpotential of the electrodes during alkaline water electrolysis, and the production of electrodes may be significantly simplified.

The present invention relates to a method for producing an electrode for alkaline electrolysis based on a composition of metal sulfides on a Ni foam substrate. The metal can be Mo, Ni, Co, Fe and/or W. In a first step S1), there is performed a metal deposition, e.g. by electroplating, the metal, Me1/Me2, being Mo, Ni, Co, Fe, and/or W, on a Ni foam substrate resulting in a metal-Ni compound being formed on and/or in the Ni foam substrate. In a second step, S2) there is performed a sulfiding on the metal-Ni compound from the first step S1). The third step S3) is an optional repetition of S1 and/or S2 at least one time. The step S1) and step S2) thereby result in the formation of electrocatalytic active nano-sites with Me1-Me2-SNi compounds. It is found that these nano-sites are capable of reducing the so-called overpotential of the electrodes during alkaline water electrolysis, and the production of electrodes may be significantly simplified.

An aqueous indium or indium alloy plating bath comprising a source of indium ions, an acid, a source of halide ions, a surfactant according to formula (I)

##STR00001## wherein A is selected from branched or unbranched C.sub.10-C.sub.15-alkyl; B is selected from the group consisting of hydrogen and alkyl; m is an integer ranging from 5 to 25; each R is independently from each other selected from hydrogen and methyl; and a dihydroxybenzene derivative according to formula (II)

##STR00002## wherein each X is independently selected from fluorine, chlorine, bromine, iodine, alkoxy, and nitro; n is an integer ranging from 1 to 4,
and a process for deposition of indium or an indium alloy wherein said bath is used.

An aqueous indium or indium alloy plating bath comprising a source of indium ions, an acid, a source of halide ions, a surfactant according to formula (I)

##STR00001## wherein A is selected from branched or unbranched C.sub.10-C.sub.15-alkyl; B is selected from the group consisting of hydrogen and alkyl; m is an integer ranging from 5 to 25; each R is independently from each other selected from hydrogen and methyl; and a dihydroxybenzene derivative according to formula (II)

##STR00002## wherein each X is independently selected from fluorine, chlorine, bromine, iodine, alkoxy, and nitro; n is an integer ranging from 1 to 4,
and a process for deposition of indium or an indium alloy wherein said bath is used.