What are the main processes for the preparation of plating solutions in electroplating equipment?


release time:

2022-05-12

​Surface conditions and processing requirements during electroplating, select appropriate steps, and perform necessary trimming processing on the surface of the parts, so that the parts have a smooth and smooth surface, which is an important part of whether to obtain a high-quality coating. What are the main processes for the preparation of plating solutions in electroplating equipment?

​Surface conditions and processing requirements during electroplating, select appropriate steps, and perform necessary trimming processing on the surface of the parts, so that the parts have a smooth and smooth surface, which is an important part of whether to obtain a high-quality coating. What are the main processes for the preparation of plating solutions in electroplating equipment?

(1) First dissolve sodium thiosulfate (or ammonium thiosulfate) with a part of water.

(2) Dissolve silver nitrate and potassium metabisulfite in distilled water respectively in anodizing equipment, and mix them under constant stirring. At this time, a precipitate is formed, and a solution of sodium thiosulfate (or ammonium thiosulfate) is added immediately and stirred continuously to completely dissolve the white precipitate, and then water is added to the required amount.

(3) Put the prepared plating solution under sunlight for several hours, add 0.5g/L activated carbon, and filter to obtain a clear solution.

The composition of additives The SL-80 additive is a condensation product of nitrogen-containing organic compounds and epoxy-containing compounds, and the use of this additive does not increase the hardness of the coating. The consumption of SL-80 additive is 100mL/(kA.h).

(4) Process characteristics This silver-plating process has high current density, bright and meticulous coating, shearing and constant temperature range, deep plating ability and dispersing ability can also be similar to cyanide silver-plating process.

(5) Precautions During the preparation process, special attention should be paid to adding silver nitrate directly to the sodium thiosulfate (or ammonium sulfate) solution, otherwise the solution will easily turn black. Because silver nitrate interacts with thiosulfate, it first forms a colored silver thiosulfate precipitate, and then gradually hydrolyzes to black silver sulfide.

The newly prepared plating solution may be microscopic yellow, or have a very small amount of turbidity or precipitation, which can be clear after filtration. Electrolysis can be carried out for a certain period of time before trial plating. At this time, black film may appear on the anode, which can be brushed off with copper wire, and the anode area should be appropriately increased to reduce the anode current density.

When filling the silver ions in the plating solution, it must be carried out according to the procedure of the preparation method, and silver nitrate cannot be directly added to the plating solution. At the same time, keep the amount of potassium metabisulfite in the bath within the normal range. Because of its existence, it is conducive to the stability of sulfur sulfate. Otherwise, the thiosulfate radical will react with the precipitation of sulfur, and the precipitation of sulfur is very unfavorable for silver plating.