A kind of neutral cyanide-free electric brush plating silver-plating solution and its preparation process and application method

Abstract

The invention provides a neutral cyanide-free brush electroplating silver plating solution. The neutral cyanide-free brush electroplating silver plating solution is prepared from, by mass concentration, 20 g / L to 30 g / L of silver salt, 40 g / L to 60 g / L of a coordination agent sodium thiosulfate, 70 g / L to 90 g / L of thiourea and homolog thereof, 20 g / L to 30 g / L of a protective agent methanesulfonic acid derivative, 20 g / L to 120 g / L of an additive polyethyleneimine, 5 g / L to 20 g / L of potassium metabisulfite, 35 g / L to 110 g / L of ammonium hydroxide and 0.1 g / L to 0.6 g / L of a stabilizer sodium citrate, the pH value of the solution is adjusted to range from 6.8 to 7.2 with dilute nitric acid or dilute sodium hydroxide, and the solution is a neutral plating solution. The invention further provides a preparation process and use method of the neutral cyanide-free brush electroplating silver plating solution. The neutral cyanide-free brush electroplating silver plating solution is prepared by mixing the harmfulless silver salt, coordination agent, protective agent and the like, the raw materials are easy to obtain, and the preparation process is simple. The neutral cyanide-free brush electroplating silver plating solution is applied to the surface of copper or a copper alloy for brush electroplating, the method is simple and practicable, and plating is stable.

Description

technical field [0001] The invention relates to the technical field of electrochemistry, in particular to a neutral cyanide-free brush-plating silver-plating solution and a preparation process and application method thereof. Background technique [0002] The DL / T486-2010 standard stipulates that the contact surface of the isolating switch and the grounding switch must be silver-plated, and the thickness of the plating layer is not less than 20 microns, so as to obtain a low contact resistance and ensure good electrical conductivity. Corrosion, wear resistance and anti-tarnish properties. The brush plating process uses a coating pen (anode) wrapped in a sheath and dipped in a special plating solution to attach to the plated part of the workpiece (cathode) and make a relative movement to form a coating. Its biggest feature is that the deposition rate is about 10 times higher than that of ordinary electroplating. . Some manufacturers often repair the unqualified silver-plated...

AI Technical Summary

Problems solved by technology

However, compared with cyanide silver plating, there are still many disadvantages: (1) plating solution stability problem: the silver ions in the plating solution will become simple substances under sunlight, which will affect the concentration of silver ions in the plating solution. The biting agent will also affect the properties of the plating solution, such as succinimide, which is easy to hydrolyze, etc.; The standard potential of copper is much more negative than that of silver. When copper and its alloy plating parts are placed in the plating solution, a substitution reaction may occur before power is applied, and a replacement silver layer is formed on the surface of the plating part. The bonding force between it and the substrate of the plating part Poor, and at the same time, some copper impurities contaminate the plating solution. Usually, pre-plating silver, immersion silver or amalgamation are used to solve this problem

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