With the study of zinc electroplating process by Electrochemical Noise (EN), it was found that the EN generated during the electroplating of large conglomerate zinc deposit has large potential oscillation amplitude and positive potential drift. However, small noise amplitude and little potential drift was seen in the case of compact zinc deposit. Any metal can be plated through zinc electroplating process, but the most common are steel and iron, on which the process offers sacrificial protection.

Steps of Commercial Zinc Electroplating Process
On the commercial scale, zinc electroplating is done by the following steps.
1. Surface of the metal is cleaned in alkaline detergent type solutions, and it is treated with acid, in order to remove any rust or surface scales. Cleanliness is essential for successful zinc electroplating, as the molecular layers of oil or rust can prevent adhesion of the coating.
2. Next, the zinc is deposited on the metal by immersing it in a chemical bath containing dissolved zinc. A DC current is applied, which results in zinc being deposited on the cathode. Alkaline zinc baths are used by the finished products, to produce a more consistent zinc thickness, especially in recesses.
3. Hence an increased protection from corrosion is provided, as the corrosion of the deposited zinc is reduced. The zinc coating can increase the time required for the formation of white rust, by ten times. Finished Products also apply sealers, which are now commonly being specified by the automotive industry, further increasing corrosion protection.

It is very difficult to obtain a uniform thickness of coating, with electroplating technique. The thickness of the coating is very much dependent on the geometry of the object being plated, and it is preferentially on the external corners and protrusions of the metal body, hence not much of it is deposited on internal corners and recesses. Zinc electroplating process is used to make a clean, smooth and corrosion resistant surface. It also makes an excellent undercoat for powder coating or paint and can leave recesses on complex shaped components without sufficient zinc coating, in order to provide corrosion protection.

The process of electroplating (also referred to as electrodeposition) is fairly simple. To start, a negative charge is placed on the object that will be coated. The object is then immersed in a salt solution of the metal that will be used to plate the object. From there, it’s simply a matter of attraction; the metallic ions of the salt are positively charged and are thus attracted to the negatively charged object. Once they connect, the positively charged ions revert back to their metallic form again and you have a newly electroplated object.

Controlling the thickness of the electroplated object is generally achieved by altering the time the object spends in the salt solution. The longer it remains inside the bath, the thicker the electroplated shell becomes. Of course there must also be an adequate amount of metallic ions in the bath to continue coating the object. The shape of the object will also have an effect on the thickness. Sharp corners will be plated thicker than recessed areas. This is due to the electric current in the bath and how it flows more densely around corners.

Before electroplating an object, it must be cleaned thoroughly and all blemishes and scratches should be polished. As mentioned, recessed areas will plate less than sharp corners, so a scratch will become more prominent, rather than being smoothed over by the plated material.

The process of electroplating began at the beginning of the 20th century and continues to evolve today. Many common objects such as tin cans are actually electroplated steel with a protective layer of tin. Medical science has experimented with electroplating to create synthetic joints with electroplated coatings, and new advances in electronics have been made with electroplated materials.

Taking Electroplate Orders
2. Commercial electroplating companies vary in their specialties. Some focus on the automotive industry, some the computer industry, and some are large enough to take on many industries and use a full range of plating technologies. In the process of writing an order, directions or specifications for the process are outlined. The electroplating company and its employees must understand the specs and fulfill the order accurately. Required delivery times, transportation methods and payment dates are agreed upon and signed for. Delayed orders or orders delivered on time or before the agreed date may be further defined by payment penalties or additional incentives.

Managing Electroplating
3. Commercial electroplating companies have the option of working with tool manufacturers and suppliers to enhance their production capabilities. From the management of the waste from electroplate processes—metals must be worked with and disposed of properly by law—to the need for hoists, material handling and purchasing, commercial electroplate businesses have a need for strong management. The scheduling and timely completion of several large orders simultaneously require close attention.

Conductive Electroplating Process
4. Traditional electroplating methods require the substrate (object) to be conductive or able to take a negative electrical charge. Once charged, the object is placed into a bath solution of salt and the chosen metal. The positive ions of the salt solution are attracted to the negatively charged object. When the two connect, the ions return to a metallic state and are now adhered to the substrate (object). Before being electroplated the object must be cleaned of any debris, oils or waxes, or the areas of dirt will not receive the process. Dimples or rough spots must be polished smooth or the plating will take on the irregularities.

Non-conductive Electroplating Process
5. Plastics have presented an interesting aspect to the plating process. Plastics are insulators, not conductors, which means charging them with a negative charge is not possible–at least not in the context of electroplating. This has given rise to all manner of processes designed to adhere metals to various forms of plastic. From using friction to developing special paints, this portion of the commercial electroplating industry is in constant discovery and development.