Alkaline semi-bright cyanide-free silver plating solution and preparation method thereof

Abstract

The invention discloses an alkaline semi-bright cyanide-free silver plating solution and a preparation method thereof. The solution is prepared from 25-30 g / L of silver nitrate, 55-75 g / L of dimethyl hydantoin, 30-45 g / L of nicotinic acid, 50-75 g / L of potassium carbonate, 10-20 g / L of sodium tetraborate and 0.1-0.4 g / L of bipyridine and bipyridine derivatives, and the pH is 9-10. The preparation method comprises the following steps: dissolving dimethyl hydantoin and nicotinic acid in water according to the volume concentration, neutralizing the solution with industrial pure potassium hydroxide with the mass fraction of 30-40% until the pH value is 8.5 or above, and sequentially adding other components according to the volume concentration to form the alkaline semi-bright cyanide-free silver plating solution. The chemical raw materials are low in cost and wide in source, the coating combination is good, the solution performance is stable, waste liquid treatment is simple, and long-term storage can be achieved.

Description

technical field [0001] The invention relates to a silver plating solution, in particular to an alkaline semi-bright cyanide-free silver plating solution and a preparation method thereof. Background technique [0002] The cyanide silver plating electrolyte uses potassium cyanide as a complexing agent for silver ions, and the CN in the electrolyte － It forms a stable complex with monovalent silver ions for electrodeposition. The composition of the plating solution is simple, easy to maintain, and the coating has good bonding force, and it is difficult to replace silver. Therefore, the cyanide silver plating electrolyte is widely used in China for copper and copper. Alloy, Nickel and Nickel alloy surfaces are electroplated with silver. However, the cyanide silver-plating electrolyte will release highly toxic cyanide in a high-temperature working environment, which poses a great threat to human life safety and causes serious damage to the ecological environment, affecting socia...

AI Technical Summary

Problems solved by technology

However, the cyanide silver-plating electrolyte will release highly toxic cyanide in a high-temperature working environment, which poses a great threat to human life safety and causes serious damage to the ecological environment, affecting social security, stability and harmonious development. The national "clean production promotion" The law clearly stipulates that "cyanide-containing electroplating" should be phased out within a time limit

At present, the cyanide-free electroplating silver plating process actively explored and developed at home and abroad, such as E-Brite50, ArgaluxNC, HELFOFABT imported from abroad MA G340, Chongqing Lidao LD7805, SL-80 of Guangzhou Electrical Apparatus Research Institute, Ministry of Electronics Industry and Southwest Normal University's iminodisulfonic acid (NS) silver plating process, but after laboratory large, medium and small tank tests show that its process The range is narrow, the stability is poor, maintenance is difficult, and many formulas and compositions have not been published. In view of this situation, we have carried out the development of alkaline cyanide-free bright silver plating solution