Nickel is the widest used electroplated coating with a myriad of functional and decorative applications. Bright Nickel is often used in the automotive, electrical, appliance and hardware industries with one of its most important functions being that of an undercoat for Chrome. In heavy deposits it will smooth out a base metal and offer significant corrosion protection.
Nickel is also used for engineering purposes where brightness is not a concern. Pure, un-brightened nickel is often used as a barrier coat for subsequent plated finishes. Sulfamate nickel produces a 99.9% pure nickel deposit that is minimally stressed making it an excellent choice for parts that will be flexed, bent or crimped. It is the recommended choice as an under-plate for lead-frames, interconnect pins, and glass-to-metal or ceramic-to-metal seals.
There is a nickel finish for almost any requirement. Nickel can be deposited soft or hard, dull to bright. The difference is dependent on process used and conditions employed in plating.
The hardness can range from 150 – 500 Vickers. Can range in appearance from matte, light gray (almost white) to a condition resembling stainless steel. Corrosion resistance is a function of thickness. Has a low coefficient of thermal expansion. Nickel plating is magnetic.
All steel parts having a hardness of Rc 40 or greater require a post bake at 375°F ± 25 for 3 hours minimum. Note: All steel parts having a tensile strength of 220,000 or greater shall not be nickel plated without specific approval of procuring agency.
Nickel also has a high melting temperature of 2647F (1452C) so it’s widely used in high temperature applications.
Specified standards are typically AMS-QQ-N-290, ASTM B689, AMS 2403, and Mil-P-2741