An electroplating bath for depositing a silver/tin alloy on a substrate. The electroplating bath comprises (a) a source of tin ions; (b) a source of silver ions; (c) an acid; (d) a first complexing agent; (e) a second complexing agent, wherein the second complexing agent is selected from the group consisting of allyl thioureas, aryl thioureas, and alkyl thioureas, and combinations thereof; and (f) optionally, a wetting agent, and (g) optionally, an antioxidant.

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 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.

Provided is a method of forming a complex plating film using multi-layer graphene metal particles. The method of forming the plating film may include preparing a powder with a metal particle structure coated with multi-layer graphene, and forming a plating film by adding the powder to a plating solution through electric plating.

A silver-plated product having a higher hardness and more excellent wear resistance than those of conventional silver-plated products, and a method for producing the same. In a method for producing a silver-plated product by forming a surface layer of silver on a base material by electroplating at a current density in a silver-plating solution which is an aqueous solution containing silver potassium cyanide or silver cyanide, potassium cyanide or sodium cyanide, and a benzimidazole (such as 2-mercaptobenzmimidazole or 2-mercaptobenzimidazole sulfonic acid sodium salt dihydrate), the ratios of the concentrations of silver potassium cyanide or silver cyanide, potassium cyanide or sodium cyanide, and the imidazole to the current density during the silver-plating (or the ratios of the concentrations of silver potassium cyanide or silver cyanide and the imidazole to the current density during the silver plating, and the concentration of potassium cyanide or sodium cyanide) are set to be predetermined ranges, respectively.

A silver-plated product having a higher hardness and more excellent wear resistance than those of conventional silver-plated products, and a method for producing the same. In a method for producing a silver-plated product by forming a surface layer of silver on a base material by electroplating at a current density in a silver-plating solution which is an aqueous solution containing silver potassium cyanide or silver cyanide, potassium cyanide or sodium cyanide, and a benzimidazole (such as 2-mercaptobenzmimidazole or 2-mercaptobenzimidazole sulfonic acid sodium salt dihydrate), the ratios of the concentrations of silver potassium cyanide or silver cyanide, potassium cyanide or sodium cyanide, and the imidazole to the current density during the silver-plating (or the ratios of the concentrations of silver potassium cyanide or silver cyanide and the imidazole to the current density during the silver plating, and the concentration of potassium cyanide or sodium cyanide) are set to be predetermined ranges, respectively.

A method for preparing a three-dimensional chitosan/silver composite scaffold includes mixing an acidic aqueous chitosan solution including protonated chitosan and a deposition accelerating agent being a soluble silver salt, spacedly disposing a cathode and an anode in the resultant suspension, and applying an electric field to the cathode and the anode so that the suspension undergoes electrodeposition. The suspension has a protonated chitosan concentration ranging from 0.7 to 2.8 w/v %, and a molarity of silver ions ranging from 4 to 60 mM. The composite scaffold prepared has columnar through-holes extending in a same extension direction and each having opposite first and second openings with the latter not less in width.

A method for preparing a three-dimensional chitosan/silver composite scaffold includes mixing an acidic aqueous chitosan solution including protonated chitosan and a deposition accelerating agent being a soluble silver salt, spacedly disposing a cathode and an anode in the resultant suspension, and applying an electric field to the cathode and the anode so that the suspension undergoes electrodeposition. The suspension has a protonated chitosan concentration ranging from 0.7 to 2.8 w/v %, and a molarity of silver ions ranging from 4 to 60 mM. The composite scaffold prepared has columnar through-holes extending in a same extension direction and each having opposite first and second openings with the latter not less in width.

In examples, an apparatus comprises a substrate having opposite first and second surfaces. The substrate includes a first opening through the substrate. The substrate includes a first sealing layer covering an inner surface of the first opening, with the inner surface extending between the first and second surfaces. The substrate includes contact pads on the second surface. The apparatus also comprises a fluid sensor having a sensor surface facing the second surface and the first opening. The apparatus further includes metal interconnects coupled between the sensor surface and the contact pads. The apparatus also includes a second sealing layer between the second surface and the sensor surface, in which the second sealing layer surrounds the metal interconnects and includes a second opening below the first opening, and at least part of the sensor surface is exposed through the first and second openings.

In examples, an apparatus comprises a substrate having opposite first and second surfaces. The substrate includes a first opening through the substrate. The substrate includes a first sealing layer covering an inner surface of the first opening, with the inner surface extending between the first and second surfaces. The substrate includes contact pads on the second surface. The apparatus also comprises a fluid sensor having a sensor surface facing the second surface and the first opening. The apparatus further includes metal interconnects coupled between the sensor surface and the contact pads. The apparatus also includes a second sealing layer between the second surface and the sensor surface, in which the second sealing layer surrounds the metal interconnects and includes a second opening below the first opening, and at least part of the sensor surface is exposed through the first and second openings.