This blog post will focus on the various types of nickel plating that are available as surface finishes. If you are interested in other elements besides chrome and nickel, my third post will go through the other elements that we currently coat with, such as gold, silver, and tin. Nickel is considered a transition metal and it is hard and ductile with good corrosion resistance. It can be applied using either a rack-process or barrel-process depending on part size and geometry. These make it a great option for coating diecast parts.
Nickel plating is yellowish-white in color and has a hard reflective finish. It has good wear resistance, solderability, and dimensional repeatability. This plating is applied over copper when used on a diecasting. It is also used as a secondary layer under chrome plating. Bright nickel is the most common variety, but should be used with caution on parts that require cold-forming as the brighteners can compromise ductility. If your component requires a cold-forming operation after plating, a Watt’s nickel can be used. It has a satin finish but is more ductile. This will ensure that the coating does not delaminate during bending or crimping.
Unlike conventional electroplating, no electric current is used for deposition during the electroless plating process. The chemically deposited nickel follows the contours of a part very closely and does not build up at the edges and corners. This yields a plated component with very uniform thickness in comparison to electroplated finishes. Electroless nickel is the most widely used form of electroless plating. Most depositions are done with an acid phosphorus bath that provides the part with excellent corrosion, wear, and abrasion resistance. Other properties include ductility, lubricity, solderability, and hardness. The three types of electroless nickel are low phos, mid phos, and high phos. These characteristics are detailed out on our surface finishes page.
Two additional electroless nickel finishes are black and dark blue. For black electroless nickel, the part is blackened to give it a metallic brown/black appearance. It’s mostly used for decorative purposes, although it also doubles the contact resistance. Dark blue has the same process as black electroless nickel except it produces a dark blue color.