Contact Finish

ibm552 Photo provided by IBM

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.
Gold Flash Palladium Nickel (Pd 80, Ni 20)
  • 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.
Tin and Tin Alloys
  • Forms surface oxides readily.
  • Very soft, poor durability.
  • Important for soldering processes.
  • Least expensive of all the plating systems.