What Does Nickel Plating Mean?
Nickel plating is the process of electrolytically depositing a layer of nickel onto a substrate. These nickel deposits are used for:
- Wear resistance
- Corrosion resistance
- Magnetic purposes
Nickel used for engineering purposes is often smooth and dull gray in appearance. Both bright and matte nickel offers an excellent degree of corrosion resistance. Nickel is also used as an under-plate for other metals such as gold and silver because it acts as a diffusion barrier that prevents any form of substrate migration to the top coating.
Parts processed with a bright nickel plating layer maintain their surface appearance and brightness over time.
Engineering nickel is used in non-decorative applications. Decorative bright nickel is used in automotive industries, household uses and hand tools.
Corrosionpedia Explains Nickel Plating
Nickel plating is the process of depositing nickel on a metal part. It may refer to:
- Nickel electroplating
- Electroless nickel plating
Nickel electroplating is a technique of electroplating a thin layer of nickel onto a metal object.
Electroless nickel plating is an auto-catalytic reaction used to deposit a coating of nickel on a substrate. Unlike electroplating, it is not necessary to pass an electric current through the solution to form a deposit. Electroless nickel plating has advantages over electroplating—free from flux-density and power supply issues, it provides an even deposit regardless of work piece geometry, and with the proper pre-plate catalyst, can deposit on non-conductive surfaces.
Nickel layers can be applied to all commonly used pure metals and alloys. Substrates include:
- Unalloyed and low alloyed steel
- Copper and copper alloys
- Zinc and aluminum alloys
Before nickel plating a substrate, it must be free of
Certain materials require special pretreatments prior to nickel plating, including:
- Stainless steel
- Aluminum alloys
Nickel electroplate is deposited onto products by placing them in an aqueous solution of nickel salts, connected as the cathode. Nickel anodes are used to complete the circuit, these dissolve during the plating process to maintain the overall nickel metal concentration in the solution. Organic additions are added to obtain leveled deposits as well as bright decorative coatings. Depending upon the additives to the nickel plating bath, finishes can range from matte through semi-bright to bright in luster. Common nickel plating baths are:
The choice of bath depends upon the desired properties of the deposit.
Nickel plating is commonly used as a base plating layer as it provides excellent adhesion between layers and can have a leveling effect on pits or other defects in the base material. High purity nickel is used in:
- Electronic and aerospace applications
- Chemical and food processing equipment
- Anodes and cathodes
- Caustics evaporators
- Heat shields