Below is a list of Electroless Nickel Plating manufacturers from Putnam, Connecticut. Electroless nickel (EN) plating is an auto-catalytic chemical reaction that results in a layer of nickel alloy, typically nickel-phosphorus or nickel-boron, to be deposited onto a solid substrate like a metal or plastic workpiece. A reducing agent, such as hydrated sodium hypophosphite, is crucial to the electroless nickel plating process because it reacts with the metal ions and allows for the nickel to be deposited.