Electroplating is used in countless industries, from automotive and industrial engineering to the manufacturing of tiny chips and parts for electronics. The process of adding a metal coating to a surface is used to give the surface the qualities of whichever metal it has just been plated with, from wear resistance and durability to a more attractive, shinier finish. In the case of electroless nickel coating, the nickel used lends a stronger, more resistant quality, making it an excellent choice for surfaces which need to withstand corrosion and wear.
Electroless nickel plating differs from a nickel coating that has been electroplated. The most notable difference is that nickel that has been plated electrolessly is less porous, providing a tougher barrier against corrosion and wear. This makes it ideal for applications where the surface will be up against the elements, such as in marine applications. This method of plating nickel is commonly used for ship and submarine parts – in fact, many marine engineers do not just consider nickel their first choice; thanks to its unique suitability, they consider it the only choice. Electroless nickel coating is also more flexible in its application, allowing it to take on the soft characteristics of nickel and fill recesses or coat evenly over uneven or jagged surfaces.
Surfaces that have been given an electroless nickel plating are not just resistant to corrosion and wear – they are also strong. Using heat treatment, nickel’s strength can be increased considerably, giving it a hardness comparable to hard chrome. Given the correct heat treatment, a nickel coating can achieve hardness in excess of 1000VHN (compared to the standards of 800 – 1100VHN set by hard chrome). In addition, nickel’s soft metal qualities allow it to achieve a more evenly distributed coating than chrome, making it a safe choice for those who are looking for a strong but uniform coating.
Another often used metal for applications where hardness is a sought-after quality is stainless steel. However, though stainless steel is a popular choice for cutlery, where it is able to withstand repeated exposure to water without corrosion or rust, it is not as well suited for more intense uses. Stainless steel will corrode when exposed to high levels of salt or low levels of oxygen, and is often more expensive to use than electroless nickel coating. Nickel gives comparable levels of hardness, as well as vastly improved corrosion resistance, making it a more popular choice for many applications.
With other benefits including being non-magnetic, less prone to staining and having a lower porosity than most other metals, electroless nickel coating is an excellent – and cost-efficient – choice for applications where hardness, uniform thickness and strong corrosion resistance is required. And with heat treatment and availability prompting many to see it as a viable replacement for hard chrome and stainless steel, it seems we will be seeing more and more uses for nickel in the near future.