The Plating Process
Plating is a metal finishing process in which one metal is coated with another. During the process, a thin layer of metal is formed on the surface of the base object. While the process is often done using precious metals, it can also be done with other metals, including brass, nickel, silver, tin, and zinc. Plating can help improve the appearance of an object, reduce wear and tear, and protect it from corrosion and other damage.
Plating is composed of several steps. Electroplating is the most common form of plating, which is the process of electrochemically depositing a thin layer of a metal onto a substrate or surface. First, the part must be thoroughly cleaned to remove any contaminants. This is often done through a process called degreasing, which involves immersing the part in a solvent such as trichloroethylene (TCE) or naphtha. Once it is clean, the part is placed in a plating solution and an electric current is applied. This causes the metal ions to migrate from the solution and the surface of the part.
The metallization process follows the electroplating process. This involves adding a thin layer of metal onto the surface of the object using chemical or physical means. Examples of metallization processes include electrolytic plating, roll plating, and spray plating.
Brightening is used after metallization to improve the appearance of the plated object. This process prints a thin layer of material onto the surface of the part. This can be done with an accelerated chemical that improves the brightness of the plating, or a physical process such as polishing or buffing.
Finally, the plated object is treated with sealing agents, lubricants, and corrosion inhibitors to protect the plating and to prevent it from wearing away over time.
Common Plating Processes
Electroplating
Electroplating is a common plating process in which metal ions are deposited on an electrically conducting surface by an electric current. By passing an electric current between a positively charged electrode (anode) and a negatively charged electrode (cathode), the current causes metal ions from the plating solution to migrate to the negatively charged cathode, where a thin layer of metal is formed on the surface of the object.
Electroplating is used for a variety of purposes, including improving the look of objects, reducing friction, protecting the object from corrosion and wear, and adding electrical conductivity.
Roll Plating
Roll plating is a process in which a thin layer of metal is applied to an object by using continuous pressure along its length. The object is placed in a rolling machine and the rollers apply pressure along its length.
Roll plating is a more cost-effective process than electroplating but it is not suited for complex shapes. It is mostly used for coating large objects or objects with simple geometric shapes.
Electroless Plating
Electroless plating is a technique in which a thin layer of metal is deposited on a surface without the need for an electric current. The plating solution contains metal ions and a catalyst, which enables the deposition of metal.
Unlike electroplating, electroless plating can be used to coat complex shapes and objects with small features. It is a more reliable process and is not prone to uneven coating or other issues that can be caused by electroplating.
Spray Plating
Spray plating is a coating process in which metallic particles are suspended in the air and sprayed onto the surface of an object. A stream of particles is propelled towards the object, forming a thin layer of metal on the surface.
Spray plating is used to coat large objects, such as car and motorcycle parts. It is also used to coat surfaces with complex geometry.
Vacuum Plating
Vacuum plating is a process in which thin layers of metal are deposited onto a surface under vacuum. The vacuum promotes the deposition of metal onto the surface, resulting in a thin, even coating.
Vacuum plating is often used for decorative purposes, such as jewelry or automotive trim, as it allows for thin, even layers with smooth surfaces.
Conclusion
Plating is a metal finishing process in which one metal is coated with another. It can help improve the appearance of an object, reduce wear and tear, and protect it from corrosion and other damage. There are several common plating processes, including electroplating, roll plating, electroless plating, spray plating, and vacuum plating. Each process has its own advantages and disadvantages, so it is important to determine the best method for a given project.
