(Enig = electroless nickel gold)
Since early 1990s the alloy surface (nickel / phosphorus & gold) is one of the most versatile surfaces. In this method, a nickel layer forms the diffusion barrier between copper and solder alloy. The gold is dissolved in the solder joint and the liability / IMC formation is done with the nickel layer. Electroless nickel-gold requires an upstream copper activation to start the nickel deposition. The nickel layer increases mechanical vias and increases the abrasion resistance.
layer thickness: 3 - 6 μm NiP and 0.05 - 0.12 μm Au
storage time: 12 Months
low / medium / high P systems : (<7; 7-10; >10 % P)