Protective treatments for gold-flashed contact 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. We were successful in developing a post-plating surface treatment that provides 0.1-μm thick gold contact finishes sufficient protection against 24 h exposure to a standard mixed-gas accelerated test; the contact resistance of a 0.1-μm gold on a nickel substrate is below 50 mΩ, while the contact resistance of the same gold flash over a matte-finish nickel phosphorus alloy is below 5 mΩ