Cobalt-hardened gold was developed to get around nickel-hardened gold patents held by one company. All electronic hardware was gold plated at that time. When the cobalt hardened process became available, many US industries switched to it because the cost was slightly cheaper and specified it for their product. I did considerable testing of comparisons of platings on electronic plated hardware and circuit boards and found no functional difference. Gold was only $35 dollars per troy ounce in those days and the charge for formulation and making it into a plating salt was about $10 for the nickel and $8 for the cobalt. Phil Hinton --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------