The Electro Nickel Plating Process

Electro nickel plating, also known as nickel electro-deposition, is becoming an increasingly popular
process for a variety of different manufacturing applications. Electro nickel plating is a process that
uses an electrical current to coat a conductive material, typically made of metal, with a thin layer of
nickel. Other metals used for electroplating include stainless steel, copper, zinc, and platinum.

Benefits of Electro Nickel Plating

In general, electroplating improves a wide range of characteristics not inherently present in the
base material. Some of these benefits include:
*ncreased resistance to corrosion

*mproved hardness

*Superior strength

*Resistance to wear

*mproved ductility

Nickel is considered useful for electroplating metal because it provides superior ductility,
corrosion resistance, and hardness. Electro nickel plating can also improve a product’s
brightness and external appearance. Different nickel-plating chemicals incorporated into
the process deliver anything from a semi-bright and fully bright cosmetic effect, to matte,
pearl, or satin finishes.

How Electro Nickel Plating Works

To transfer nickel onto the surface of a product properly, a negative charge must be
applied to the base material. To achieve this, the product is typically attached to a rectifier,
battery or other power supply via a conductive wire. Once attached, a rod made of nickel
is connected in a similar fashion to the positive side of the rectifier or power source.

Once the initial steps have been completed, the base material is submerged in a solution
that features a salt with a chemical makeup, including the electroplating metal. With
electro nickel plating, this solution consists of water and nickel chloride salt. Due to the
electric current present in the solution, the nickel chloride salt dissociates to negative
chloride ions and positive nickel cat-ions. The negative charge of the base metal then
attracts the positive nickel ions, while the positive charge of the nickel rod attracts the
negative chloride anions. Through this chemical reaction, the nickel in the rod oxidizes
and dissolves into the solution. From here, the oxidized nickel is attracted to the base material,
and subsequently coats the product.

Current Density in the Electro Nickel Plating Process

Electro nickel plating involves a wide range of current density levels. Current density directly
determines the deposition rate of nickel to the base material—specifically, the higher the current
density, the quicker the deposition rate. Current density, however, also affects plating adherence
and plating quality, with higher current density levels delivering poorer results. Therefore, the
optimal level of current density depends on the type of base material and specific type of results
the final product requires.

One way to avoid working at lower current densities is by employing a discontinuous direct
current to the electroplating solution. By allowing between one and three seconds of break time
between every eight to fifteen seconds of electrical current, high current densities can produce
a higher level of quality. A discontinuous current is also beneficial for avoiding over-plating of
specific sections on the base material.

Strike Electro Nickel Plating

Another solution to the current density issue involves incorporating a strike layer to the initial
electro nickel plating process. A strike layer, also known as a flash layer, adheres a thin layer
of high-quality nickel plating to the base material. Once up to 0.1 micrometers of nickel coats
the product, a lower quality current density is used to improve the speed of product completion.
When different metals require plating to the product’s base material, striking can be used. In
cases where nickel serves as a poor adherent to the base material, for example, copper can
be a buffer prior to the electro nickel-plating process.

Pre-treatment Process for Electro Nickel Plating

Proper pre- and post-treatment of the base product has a direct correlation to the quality and
deposition rate of electro nickel plating. To help ensure uniform and quality adhesion,
chemical or manual preparation includes the following three steps:
*Pre-treatment surface cleaning: Surface cleaning entails eliminating contaminants
through the use of solvents, abrasive materials, alkaline cleaners, acid etch, water,
or a combination thereof.
*Surface modification: Modifying the exterior of the base product improves adhesion
through processes such as striking or metal hardening.
*Post-treatment surface cleaning: Performing Finishing operations, such as rinsing,
end the electroplating process
Once pre-treatment cleaning is complete, testing the level of cleanliness in the base material
prior to beginning the electro nickel plating process is a good idea. To do this, the
waterbreak test is recommended. In this test, the treated substrate is rinsed and held
vertical. If contaminants such as oils are absent, then a thin sheet of water remains
unbroken across the entire surface of the base material.