What is Metal Finishing & How Does It Work?
If we take a quick look around us, we will find there are one or more objects that include some kind of metal in it. Since thousands of years, metal has played a key role in our lives and has been a key constituent of nearly all innovation in technology. Is it even possible to imagine a life without the innumerable metal products in our lives? All metals, whether they are the relatively common ones like zinc, nickel, tin, and copper or the precious metals like silver, gold, and platinum, have some limitations that need to be worked on. This is where metal finishing comes into the picture.
What is Metal finishing?
Metal finishing is a term that describes the coating the surface of a metal part or component which is generally a substrate. The process of finishing also includes the process of cleaning, polishing and improving the surface of the metal. The term metal finishing is sometimes used interchangeably with plating. Electroplating is the process that involves the deposition of metal ions onto a substrate with the help of an electric current. Metal finishing, however, is not just limited to electroplating. There are many different kinds of processes that are used in the metal finishing industry and many have their own unique benefits.
There are many useful reasons to have an industrial metal finishing:
The impact of corrosion is limited.
It improves the metal’s chemical resistance.
It enhances the appearance of the metal.
It strengthens the substrate and increases its resistance to wear and tear.
The solderability of the metal increases.
It serves as a primer coat and thus, promotes the adhesion of paint.
The surface becomes electrically conductive.
It reduces the effect of friction on the metal.
It helps in cleaning, and polishing of the metal and removal of any defects from the surface.
Here are some of the ways through which industrial metal finishing is done.
The first process is electroplating, which we have already mentioned above. Electroplating is also referred to as electrodeposition. In this process, metal or a metal alloy is deposited onto the surface of a substrate. A liquid consisting of dissolved ions of the metal and the substrate then has an electric current passed through it. The metal object will act as a cathode and attract the metal ions found in the liquid. Before the plating process, cleaning, rinsing, and stripping are often done to prep the surface.
In electroless plating, just like electroplating, the substrate is placed in a liquid solution with the preferred metal in it. Apart from the source metal, the liquid also contains a complexing agent that ensures that the metal solution and the various chemical in it maintain stability. The difference between electroplating and electroless plating lies in the way that deposition is done. The metal coating is applied using a chemical reaction instead of electricity.
Electropolishing is a metal finishing process that can be considered as the opposite of electroplating. In the electroplating process, metal ions are deposited on the surface of the substrate; whereas in electropolishing, metal ions are actually removed from the substrate. The end result is smooth texture on the surface. The object is immersed into an electrolyte bath, making it an anode. It is connected to a terminal providing a DC power supply and that serves as a cathode. All the debris, burrs, unevenness from the surface of the metal is removed.
Just like electro polishing, buff polishing also smoothness and cleans the substrate surface. However, unlike electro polishing, buff polishing does not require any electro chemical reaction. In this process, there is a machine which is equipped with a cloth wheel. The wheel is used to buff the surface. It leads to a highly glossy and decorative finish to metallic objects.
These are just some of the many metal finishing processes. When deciding what process works best for you, you need to take into account numerous factors such as the production speed, the hardness of the substrate material, and budget constraints. At Diamond Brite Metals, we help you settle on a metal finishing process that best serves your requirements.