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

Abstract

The invention discloses an alkaline full-bright cyanide-free silver plating solution and a preparation method thereof. The solution comprises the following components and conditions: 25-30 g / L of silver nitrate, 130-150 g / L of dimethyl hydantoin, 55-75 g / L of potassium pyrophosphate, 50-70 g / L of potassium carbonate, 15-25 g / L of potassium nitrate and 0.01-0.05 g / L of Bi < 3 + >, and the pH value is 9-10. The preparation method comprises the following steps: dissolving dimethyl hydantoin with 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 more than 8.5, and sequentially adding other components according to the volume concentration to form the bright cyanide-free silver plating solution. The cyanide-free silver plating solution is simple in component, low in chemical raw material cost, wide in chemical raw material source, good in plating combination, stable in solution performance, simple in waste liquid treatment and capable of being stored for a long time.

Description

technical field [0001] The invention relates to a silver plating solution, in particular to an alkaline full bright cyanide free silver plating solution and a preparation method thereof. Background technology [0002] The cyanide silver plating electrolyte uses potassium cyanide as the complexing agent of silver ions, and CN in the electrolyte － It forms a stable complex with monovalent silver ions for electrodeposition, which has the advantages of simple bath composition, convenient maintenance, good coating adhesion and difficult to produce replacement silver. Therefore, cyanide silver plating electrolyte is widely used in electroplating silver layers on the surfaces of copper and copper alloys, nickel and nickel alloys in China. However, the cyanide silver plating electrolyte will release highly toxic cyanide in the high-temperature working environment, which poses a great threat to human life safety, causes serious damage to the ecological environment, and affects the safety,...

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, causes serious damage to the ecological environment, and affects social security, stability and harmonious development. The law clearly stipulates that "cyanide-containing electroplating" should be phased out within a time limit

At present, China is actively exploring and researching new cyanide-free electroplating processes, such as E-Brite50, ArgaluxNC, and 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 scope is narrow, the solution stability is poor, maintenance is difficult, and many formulas and compositions have not been published. In view of this situation, we have developed an alkaline all-bright silver plating solution