Definition - What does Immersion Plating mean?
Immersion plating is the process of applying adhering layers of nobler metals to another metal's surface by dipping in a nobler metal solution ions to produce a replacement reaction. It causes the deposition of a metallic coating on a base metal from solutions that contain coating metal. In this, one metal is typically displaced by metal ions that have lower levels of oxidation potential, relative to the metal ion being displaced.
Immersion plating is also utilized to improve electrical properties as well as to enhance organic coatings or adhesive coating’s bonding to the substrate.
Immersion plating is also known as metal replacement and dip plating.
Corrosionpedia explains Immersion Plating
Immersion plating is distinct from various electroplating processes in the sense that there is no presence of external current. This process follows the principle: when metal components such as copper are put into an electrolyte with nobler metal ions, the less noble component or metal will undergo dissolution. This, in turn results in the release of electrons, allowing highly noble metals to settle down.
Unlike with electro-less plating, the deposition of metals is halted once the plated object is completely coated with metals of a higher nobility. This type of plating occurs at high temperatures: in gold, immersion takes place at 80° to 90°C, while in silver the process begins at 50° to 60°C.
Overall, immersion plating alters metal surfaces to improve:
- Wear and corrosion resistance
- Electrical resistance
- Electrical conductivity
- Appearance and reflectivity
- Chemical resistance and hardness
- Torque tolerance
- Bonding capabilities