We use cookies. They help to improve your interaction with the site.
Electronics news

Immersion silver plating

Immersion silver plating is the process of depositing a thin layer of silver on a substrate through a redox reaction.

Unlike traditional electroplating methods, which rely on an external electric current, immersion silver plating uses a chemical solution containing silver ions, reducing agents and other additives to facilitate the transfer of metal ions to the surface.

The chemical composition of the immersion silvering solution consists of the following components:
1. silver ions. The main source of silver for deposition, often in the form of silver nitrate AgNO₃ or silver cyanide AgCN.
2. Reducing agents: formaldehyde, glucose and hydrazine.
3. Complexing agents. Substances that help control the rate of silver deposition and ensure uniform coverage. For example, ammonia, cyanides, and organic acids.
4. pH Regulators. Substances that maintain the desired pH of the solution. The pH affects the rate of deposition and the quality of the coating.

The reduction reaction usually occurs in the presence of a catalytic surface, which can be the PCB substrate itself or a pre-coated layer of palladium or tin.