Can I save money by switching from Gold plated contacts in my cable connectors to Tin plated contacts?
Before you can make that decision you have to look at the trade offs between the virtues of the two materials. While Tin plated contacts can be up to 4 times cheaper than the same contact plated in gold there are issues to consider regarding mating cycles, conductivity and resistance to oxidation.
Gold is very durable. Gold contacts can be mated and unmated many more times before degrading to the base metal than the same connector using Tin plating.
Gold is also very resistant to corrosion; Tin on the other hand is very susceptible to corroding over time due to environmental conditions (high humidity, direct exposure to wet conditions especially salty wet conditions).
Tin is also subject to a process called Fretting. Fretting occurs in environments where mechanical vibrations cause small movements between the connectors surfaces or where expansion and contraction through temperature is present. The Fretting process can wear down the Tin contact surface over time and expose the base metal, which is even more prone to oxidation.
Tin can also be subject to galvanic corrosion. If a tin contact is mated to a dissimilar type of contact material (usually gold) as current flows across the surfaces metallic oxides can form at that union. These oxides have a relatively high resistance, which can degrade current flow.
Gold also has a lower contact resistance than Tin. Gold has a mated maximum contact resistance expectation of 20 milliohms whereas Tin is 50 milliohms.
So how do you chose if you should switch from Gold to Tin plating on cable contacts?
If you go down this checklist and you can check all of these boxes you should be ok with the switch from Gold to Tin if the Cable Connectors will:
*have a low number of lifetime mating cycles
*be used in a relatively Dry Environment.
*be free from continuous mechanical vibration
*be free from extreme temperature swings
* be mated to a similar (Tin) plated contacts
*operate above 50milliohm threshold