Nickel electroplating is one of the oldest coating and plating processes known and offers several benefits to a broad variety of industries. Since it is an affordable option, it has become a popular due to its low cost and appealing benefits. Industries from aviation to telecommunications benefit from nickel electroplating.
History of Electroplating
Electroplating was invented by an Italian chemist named, Luigi Brugnatelli, in 1805. He was considered to be one of "The Fathers of Science" and performed electrodeposition of gold using the Voltaic Pile, which was discovered by his colleague Aliessandro Volta in 1800. His work with electroplating was published in the Belgian Journal of Physics and Chemistry. However, Luigi Brugnatelli's work was rebuffed by Napoleon Bonaparte, the dictator, causing him to suppress any further publications.
Nearly 40 years later, John Wright of Birmingham, England discovered that potassium cyanide was a suitable electrolyte for gold and silver electroplating. John Wright was the first one who showed that electroplated items could be immersed in a tank of silver held in a solution with an electric current passing through.
Henry and George Richard Elkington patented the rights to John Wright's electroplating process in 1840. While there were several other inventors vying for these rights, the Elkington brothers were the first to possess the patent. They held a monopoly on electroplating for many years thanks to the patent for an inexpensive method to electroplate.
Nickel electroplating is a process of applying a nickel coating onto a metal surface by means of electrolytic deposition. In order for parts to be plated, they must be clean and free of dirt, corrosion, and defects so the plating can be applied. In order to prepare a product, it must be cleaned and protected before the plating process. To prepare a part, a combination of cleaning, masking, heat treating, pickling and etching are commonly used.
Preparing A Product for Electroplating:
- Masking is where a specific area of a surface can be covered to ensure that it is not exposed during the anodizing or electroplating process.
- Heat Treating is a process to soften the metal and improve formability. It makes parts harder to improve the strength.
- Pickling is a treatment that is used to remove impurities like stains, inorganic contaminants, rust of ferrous metals, which could potentially affect the usage of the product. Typically, an acid solution called "pickled liquor" is used to remove the impurities.
- Etching is a process of using strong acid or mordant (dye fixative) to cut into the unprotected parts of a metal surface to create a design in the metal.
After the part has been prepared, it is immersed in an electrolyte solution and is used as the cathode (an electrode from which a conventional current leaves a polarized electrical device). The nickel anode is dissolved into the electrolyte to form nickel ions. These ions move through the solution and deposit on the cathode.
Nickel electroplating requires a nickel strike process for adhesion and then a chromium finish is added to create a higher corrosion resistance and anti-tarnish property to the nickel deposit. A strike layer (or flash layer) adheres to a thin layer of high-quality nickel plating to the base material.
Nickel electroplating baths can deposit both bright and semi-bright nickel. In most instances, bright nickel is used for ornamental or decorative purposes as well as for corrosion protection. Typically, semi-bright deposits are used for engineering applications, where higher corrosion resistance, ductility, and electrical conductivity are necessary.
Nickel Plating Benefits
It is common for nickel plating to be used for a variety of reasons or uses including:
- Corrosion resistance: Nickel plating provides protection from oxidizing and rusting with a coating,which shields the base metal.
- Solder-ability: The plating allows you to solder difficult metals.
- Durability: Mechanical parts and tools often benefit from an increased hardness making them more durable and longer lasting. thicker platings can often make an object magnetic.
- Ornamental purposes: A variety of colors and finishes can give an aesthetically pleasing look to an object. From brushed stainless steel to metallic black, there is a broad range of options available making nickel appealing to lots of industries.
Nickel electroplating is an appealing option for all types of industries ranging from aerospace and aviation to automobile and telecommunications due to its versatility. There are also several types of nickel plating, which give it different appearances and durability attributes.
Types of Nickel Electroplating
Bright Nickel Plating-Due to high levelling properties, bright nickel plating hides polishing lines and other imperfections of the surface of a material, which makes it an appealing option. It produces a bright mirror like finish due to its elevated sulfur content and is also has good conductivity. However, it is not as corrosion resistant as other types of nickel plating. It is ideal for car parts like trim work, bumpers, rims, and exhaust pipes.
Electroless Nickel Plating– This process differs from other nickel plating in that it does not use an electric current application process, but rather uses an auto-catalytic reaction. Its even coating and ability to deposit on surfaces which are non-conductive is appealing to many. It is ideal for preventing corrosion and wear for anything needing an increased hardness.
Dull Nickel Plating-Producing this hard wearing dull, matte finish is a very similar process to bright nickel plating process. Dull nickel plating is extremely corrosion resistant and malleable. It is ideal for machine parts and springs since its coating can build thickness and is useful for abrasion and dimensional correction purposes for movement.
Professional companies like Asheville Metal Finishing can assist your business with finding the best option for your products. A professional can help ensure you find the best nickel plating choice as well as determine the most cost effective option for your products. Asheville Metal specializes in bright nickel plating. Since nickel electroplating is a science, you want to make sure you leave it up to a professional to determine the best solution for you.