Cyanide-free silver plating method

Abstract

The invention discloses a silver nitrate-dimethyl hydantoin system cyanide-free silver plating process, and belongs to the field of electrosilvering. A plating solution is prepared as follows: the concentration of dimethyl hydantoin is 50-200 g / L; the concentration of silver nitrate is 8-30 g / L; the concentration of sulfamic acid is 50-150 g / L; the concentration of potassium hydroxide is 65-125 g / L; and components and contents of a brightening agent are as follows: 1 g / L of salicylic acid, 0.8 g / L of 22 dipyridyl, 1 g / L of alanine, and 1 g / L of imidazole. The substances are diluted to 1 L with water or distilled water to become the brightening agent. The plating solution is excellent in stability; silver ions in the plating solution are not replaced with such monometals as copper and nickel and alloy substrates; the silver preplating or the silver dipping is not needed for plating pieces; plating layers have the characteristics of excellent binding force, brightness, smooth surface, good tarnishing resistance, corrosion resistance and wear resistance; and the cyanide-free silver plating can compete with or even be superior to the cyaniding silver plating in some respects, satisfies the requirements for the application in such fields as the decorative electroplating and the functional electroplating, and has higher promotion and application values.

Description

(1) Technical field [0001] The invention relates to a cyanide-free electroplating silver process. The silver coating obtained by the method has fine crystals, bright surface and good binding force, and belongs to the technical field of electroplating. (2) Background technology [0002] Electroplated silver is widely used in electrical appliances, electronics, communication equipment and instrumentation manufacturing industries. With the rapid development of my country's electronics industry, not only the demand for silver plating is increasing, but also the scope of application is becoming wider and wider. Almost all traditional silver plating solutions contain highly toxic cyanide, but most of the current research on cyanide-free silver plating has defects such as poor stability of the plating solution and unsatisfactory appearance of the plating. (3) Contents of the invention [0003] In order to overcome the above defects, after long-term efforts, the bright silver pla...

AI Technical Summary

Problems solved by technology

Almost all traditional silver plating solutions contain highly toxic cyanide, but most of the current research on cyanide-free silver plating has defects such as poor stability of the plating solution and unsatisfactory appearance of the plating layer.