A wide variety of metals are used in plating components using the electroplating, electroless plating or selective plating processes. Often, the type of metal to be used depends on the type of application. Be it giving a finished metallic look to improve aesthetics, or be it changing the chemical, physical and mechanical properties of a component for better performance under stress, each metal and alloy brings a specific set of advantages in plating.
Here are some of the important metals and alloys used in plating:
Gold: Gold plating is generally applied to small components due to the high price of the metal. Apart from jewellery, gold plating is applied to components such as connectors as gold has high electrical conductivity and resistance to oxidation. Gold remains a coveted metal due to its unique physical and mechanical properties and is much rarer than copper which also displays similar properties.
Silver: Silver also possess high electrical conductivity. It tends to be highly valued and is used mostly in jewellery and decorations. However, it can enhance the electrical conductivity of components. Even so, the benefits conferred by silver may not hold over the long term, and many other cheaper metals perform better than silver in a number of applications.
Copper: As opposed to gold or silver, lower cost and high electrical conductivity make copper as well as its alloys popular plating materials in various sectors of the industry. It is used widely in the manufacturing of circuit boards and electronic components. In addition to high corrosion resistance and heat transfer ability, copper also possesses a high plating efficiency. Even though stainless steel costs less than copper, its thermal conductivity is only 1/30 that of copper. This makes copper the metal of choice for heat transfer applications.
Zinc: Zinc is used to plate a wide array of components from automotive parts, fasters, and nails to currency coins. Galvanizing process often uses zinc through electroplating.
Nickel: Nickel plating is more commonly used in electroless plating. Many objects of everyday use such as kitchenware, plumbing fixtures, doorknobs etc. are plated with nickel. The popularity of many nickel alloys also makes the metal the most widely used in plating.
Chromium: Chromium plating can help reduce friction and improve resistance to corrosion. Apart from this, it is also used for decoration due to its shiny clean surface finish. Many components in the automobile sector are electroplated with chromium for decorative purposes.
Cadmium: Cadmium is used mostly to plate components that require enhanced paint adhesion. Apart from this, the metal also increases corrosion resistance and protects the components from wear and tear. Almost all conductive metals can be plated with chromium, making it a widely used metal in all sectors across the industry.