Since base metals oxidize, the contact finish system is the first line of defense for the protection against the environment. The common plating systems used are:
- This is a noble material and does not form an oxide or film formation.
- Nickel or cobalt is used to increase hardness.
- Pure gold is soft and is prone to galling creating high mating forces and wear.
- Prone to porosity at thickness levels levels < 30 µinch.
- Most expensive of the plating systems.
- Most durable of all the plating system (hard).
- Poor in high temperature and fretting applications.
- Must be used with a gold flash to offset tendencies to form film and prevent oxide formation (due to nickel).
- Pd can form a frictional polymer.
- Forms surface oxides readily.
- Very soft, poor durability.
- Important for soldering processes.
- Least expensive of all the plating systems.