Protective treatments for gold flashed finishes with a nickel substrate

While precious metals such as gold or gold flashed palladium are preferred contact materials for connectors, cost considerations dictate the actual thickness used and hence the corrosion resistance. A method of preventing corrosion on contacts and providing connectors with uniform performance at a minimal cost is desirable. The authors were successful in developing a post-plating surface treatment that provides 0.1- mu m-thick gold contact finishes sufficient protection against 24-hr exposure to a standard mixed gas accelerated test. After the exposure, the contact resistance of 0.1- mu m gold on a nickel substrate is below 50 m Omega , while the same over a matte-finish nickel phosphorus alloy is below 5 m Omega .<>