Electroplating is the process of using a metal to coat a surface or object. There are many reasons this is done, from improved corrosion and abrasion-resistance (particularly in marine engineering, where resistance to sea abrasion is a major factor in the effectiveness and longevity of a product) to superior electrical conductivity to an increased and improved thickness to even decorative and aesthetic purposes. Electroplating is extremely common, used in industries all across the world – including engineering, manufacturing, and construction. Many different metals can be used for this purpose, but easily the most popular is nickel plating, with electroless nickel plating being used worldwide for a huge variety of applications.
So what kind of metals are used, and why is electroless nickel coating the clear winner?
Tin is a soft metal that is relatively malleable (meaning it can be used on surfaces with crevices or uneven edges) and best of all, is widely available thanks to its abundance. Tin is commonly used in cheaper operations, thanks to its low price. Similar to tin, zinc is also a very abundant metal, and most commonly used on small items such as nuts, bolts, and screws. Many a copper finishing company will point to copper as another good choice of soft metal, particularly in decorative applications – though it is also used in applications where its excellent electrical conductivity is needed, such as in the manufacture of electronic circuit boards.
Precious metals are also sometimes used. Gold is a common and popular plating choice for jewellery, as is silver. Silver is also used in applications where its superior hardness gives it an edge.
However, it is electroless nickel coating that is the most common choice for manufacturers across the globe. “Electroless” refers to the fact that unlike typical electroplating, the process is non-galvanic, making it simpler and meaning it does not require the extra equipment that typical electroplating does. It also means that engineers can control the thickness and hardness of the nickel, as well as the deposition for a smoother, more even coating. Electroless nickel plating is popular for several different reasons: like tin, zinc, and copper, nickel is a soft metal, meaning that it can be applied evenly to uneven surfaces and crevices thanks to its superior malleability. Nickel also offers unmatched corrosion-resistance, and since the application of heat can be used to increase its hardness, it also offers superior wear resistance.
Electroless nickel coating is used for a range of applications, from marine engineering and automotive engineering to being used as an undercoat to improve hardness before a covering coat of gold or another metal. Other uses include surfaces or items which see a great deal of everyday usages, such as doorknobs – being touched every day, no matter how gently, will inevitably mean that the superior wear resistance of electroless nickel plating is necessary to prevent a tarnished, weakened surface.
It’s clear why electroless nickel coating is so widely used – it offers unparalleled benefits in many different areas, making the possible applications for it seemingly endless. Who knows what it will be used for in the future?