Metal finishing has evolved from an empirical craft to a critical technology founded on scientific principles in just a few decades. 1 Modern electroplating is a type of metal finishing that is utilised in a variety of industries, including aerospace, automotive, military, medical, RF microwave, space, electronics, and battery production. Metal ions in solution are attached to a metal substrate by electrodeposition in this electrochemical process. Parts must be cleaned and then put through a series of chemical baths to prepare, or activate, them so that a strong bond, and hence strong adhesion, can be formed during the electrodeposition process.

Many variables and components in the electroplating bath must be closely monitored. At the plating bath, a power supply delivers direct current to the pieces and electrical connections. The attraction of ions in the solution to the surface of the metallic portion is started by this flow of current. One mole of metallic ions in solution will attach to the component for every mole of electrons delivered to it. In addition, a chemical reaction involving ion reduction and oxidation happens at the part’s surface.

Before electroplating, an engineer or designer should think about the following things.

During the electroplating process, pieces are nested. Because electroplating involves both an electrical and a chemical reaction on the part’s surface, exposure to the plating chemistry is crucial to the finished product’s overall performance. Nesting pieces will cause a lack of adhesion or coverage on the finished part’s surface.

The plating thickness should be considered while defining tolerances on key part dimensions. This also implies that the fit into the overall assembly must be taken into consideration.

The setting in which the completed pieces will be used. This will aid in determining the plating thickness required to protect a part from corrosion or numerous wear cycles, for example.

Because electroplating uses current to start a reaction on a part’s surface, the part’s overall geometry will affect the current distribution, also known as current density, throughout the part’s surface. On characteristics like sharp corners, bends, and threads, plating tends to build up. This problem can be avoided by using advanced plating techniques.

Drainage of plating solution (surface preparation or plating bath chemistry) to ensure that the interior surfaces of items are adequately coated and the plating has sufficient binding strength. This may necessitate the insertion of a weep hole during the design phase for some elements.

The intended use and features that are required (e.g., conductivity, low friction, high strength and resistance to corrosion, wear, etc.). These parameters should be sufficient for determining the type of metal to utilise for each specific part’s finish.

What Are Electroplating’s Advantages?

Electroplating is a process that improves or modifies the characteristics of a metallic component.

A manufacturer may want better wear and abrasion resistance, corrosion protection, greater lubricity and lower friction, improved EMI/RFI shielding, temperature and impact resistance, improved conductivity, improved solderability, reduced porosity, added hardness or strength, or to add thickness too small or undersized parts, depending on the part’s intended use.

The overall aesthetics of the completed product are often as significant as the mechanical or functional aspects that may be adjusted throughout the electroplating process.

Electroplating Methods and Types

Plating operations that specialise in speciality plating can plate a variety of base materials with a variety of surface finishes:

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Depending on the application, the plating substance, plating procedure, and parts to be plated will all differ.

Gold plating is one of the greatest alternatives for electrodes, current-carrying pins, and circuit board components because of its excellent electrical conductivity. In a wide range of settings and climates, gold is particularly suited for protection against extreme heat and corrosion. Because of its lower electrical resistance, silver plating is frequently used for electronics (instead of a copper “flash”). Nickel plating is popular because it provides higher chemical and corrosion resistance, as well as increased wear resistance, which extends the life of products.
Nickel can be used as a silver equivalent in electronics or as a steel coating to replace items made of more expensive stainless steel.

Nickel also has a bright surface finish that may be customised to meet the needs of the customer. Before the final layer of metal is placed, copper plating is usually used as a plating layer. Circuit boards, automobile parts, and the defence industries all use this surface finish. Before the final metal is deposited, copper might be added to a part to improve the overall aesthetics of the finished item. If a single metal does not offer the desired qualities, two or more metals can be co-deposited for an electroplated alloy deposit. Electro-Spec, Inc., a speciality plating firm, offers a copper/tin/zinc alloy known as Tri-Metal or Tri-M3 as an example.