One of the misconceptions about Electroless Nickel Immersion Gold (ENIG) is that it remains solderable for an unlimited amount of time. This misunderstanding is based in the fact that gold is a noble metal. Noble metals are metals that are resistant to oxidation and corrosion. Hence the belief that ENIG remains solderable since gold is the metal that we see. Some people in the electronics industry are surprised when they learn that ENIG has a solderable shelf life of (more…)
Posts Tagged ‘immersion’
Printed circuit boards that are coated with immersion silver must be handled with care and stored properly. The shelf life of immersion silver is typically 12 months. Properly stored boards protected from the environment can far exceed that limit. The following considerations must be taken into account in order to preserve the solderability of the finish. (more…)
Immersion silver is a solderable surface finish applied to the bare copper of a printed circuit board. The role of the immersion silver is to prevent the copper from oxidizing. When soldering to a board with immersion silver a copper-tin intermetalic alloy is formed. The silver is absorbed into the solder joint. Immersion silver is applied as a last operation. It is common for it to be applied to individual boards in piece or pallet form after the parts have been removed from the process panel. This minimized handling contamination and visual defects to the plated surface.
Immersion Silver has the following advantages… (more…)