Metal is a popular material that is being used in a wide range of industries such as automotive, aerospace, and other consumer applications that use aluminum or titanium for the manufacturing of products. As we know, metal is vulnerable to corrosion when exposed to the natural environment. Even some lightweight alloys offer superior corrosion resistance naturally, but the treatment on the surface is still inevitable on the finished product because the finishing process can provide better longevity, quality, and performance of the product. Metal finishing is the process of applying certain layers of coating or treatment to the surface of the metal part or component. The part or component is known as substrate. There are many types of coating materials and processes available for you to choose from. Each type is designed for specific substrates and environments. It is important for you to understand the types of metal coating and finishing process in order to choose the right protective coating, especially if your business involves the manufacturing of products that are made of different types of metal.
Benefits of Coating your Metal Parts
Generally, the purpose of the coating is to protect the metal from corrosion and improve the performance of the products. Besides, metal coating can achieve other benefits and purposes such as increasing the surface thickness, torque tolerance, durability, and surface strength. It also can improve electrical conductivity which is useful for industrial components and applications. The metal also becomes highly resistant to damage with the protective coating, such as increased electrical resistance, greater chemical resistance, greater water resistance, etc.
Common Types of Metal Coatings
1. Anodizing
Anodizing is the process of forming a protective oxide layer on the surface of the metal. Other non-ferrous metals also can be anodized, but the most common type of metal for this process is aluminum as it responds most effectively to the anodizing process. The forming of the oxide layer becomes more quickly and thicker under this process than if it was produced naturally. The anodizing process makes the metal surface to be more resistant to corrosion and creates a more adhesive surface for extra coatings if needed.
During the anodizing process, aluminum components are immersed in the tank filled with the electrolytic solution with a cathode. An electrical current is then passed through the aluminum and makes it oxidize to generate a layer of protective barrier on the surface of the material. Anodizing is a natural process that is non-toxic and won’t generate any dangerous by-products. Anodized surface is also easier to maintain when compared to other coatings. It is a long-lasting coated surface and can be easily cleaned up with the use of mild detergents. The coating is also chemically stable and won’t be decomposed under normal conditions.
As mentioned before, anodizing can be applied to other non-ferrous metals as well. But this process is not suitable for ferrous metals like steel and iron as they cannot be anodized.
2. Galvanizing
Galvanizing is another popular protective coating for metals such as steel and iron. During the process, the metal is immersed in the molten zin bath. When it is removed and exposed to the atmosphere, the metal will react with oxygen and carbon dioxide to form a protective zinc carbonate layer on the surface. The zinc oxide coating adheres tightly to the metal substrate which makes it very durable and stable. We have introduced the characteristics and advantages of galvanizing before. You may find more information about the galvanizing from the following link - https://www.mechero.my/post/what-are-the-characteristics-and-advantages-of-galvanizing
3. Electroplating / electrodeposition
Electroplating is a process that adding a thin layer of metallic particles to the surface of another metal object. The process is done by immersing the object into a bath that contains a dissolved metal such as chromium, cadmium, or nickel, and then running an electrical current through it. Electroplating offers an aesthetically pleasing surface finish which makes it an ideal coating for ornaments or jewelry. However, this process is hard to achieve uniform thickness and a repeating coating may be required for the parts subject to abrasion.
4. Paint Coating
Paint coating refers to the application of liquid paint. This is the most cost-effective and accessible type of coating. There are a variety of paint formulations available for different types of metal and performance requirements. The paint coating is gradually replaced by other coating methods as it may contain toxic elements and is more likely to fade or flake off when exposed to the environment. But there are some applications that liquid paint still remains the preferred choice, such as when the object requires more color selections, the object requires a smoother coating surface, or when the object requires lower cure temperatures.
5. Powder Coating
Powder coating uses a powder-based substance to coat on the object and it is another relatively inexpensive option for metal coating. Powder coating is an electrostatic process where the coating particles are electrostatically charged with a polarity that is opposite to the object to be coated. The powdered particles are adhered to the surface due to the difference in charge. The coated object will then be heat-treated to harden the coating. Powder coating is durable and has little or no volatile organic compound (VOC) emissions which is a more environmentally option over liquid paint. However, the coating process required special spray booths and spraying equipment which may lead to a higher initial cost. It also has limitations on the size of objects to be coated.
In comparison with paint, powder coating can be applied more efficiently and provide thicker protective layers that increase the corrosion resistance of the material. In this case, it also means that this process is not suitable for the object that wants to achieve thin coating layers.
There are many types of coating methods for metal to improve their properties and performance. The right method chosen will greatly increase the quality of the product and extend its useful life in a way to save your maintenance cost in the long run. MecHero Malaysia provides a variety of metal coating services that meet your requirement. You can always contact us at +6011-7000 7687 or email us at my.mechero@gmail.com for an inquiry about metal coating in Malaysia. As a steel and online hardware store in Malaysia, we also supply a wide range of steel materials, general hardware, or mechanical components. Tell us your requirements now and we can advise you accordingly.
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