Chromate and chrome finishes are quite popular among surface finishing providers. These range from powder coating to anodizing to chrome and more. Chromate and chrome are quite common, and most people do not know the difference between them.
What is Chromate?
Chromate is a salt that is a strong oxidizing agent. Chromate treatment is a surface finishing technique that involves the application of chromium compound solution to the metal surface. In this way, it creates a protective coating. This results in a chemical reaction between the chromic acid and base material. The resulting compound is a protective film that is resistant to physical and chemical abrasion and corrosion.
Chromate surface finishing involves washing, degreasing, and etching to improve the adhesiveness of the metal surface. After this, the chromate solution is applied through either immersion or spraying. The resulting film passivates the surface and makes it inactive to chemicals. Also, it protects the metal from galvanic corrosion.
The appearance of the coat varies from dark brown to yellow. Usually, the color of the cause depends on coat thickness and metal type. Most manufacturers prefer thicker coatings as they provide improved corrosion protection.
Chromate Treatment Benefits
These are some of the reasons surface finishing providers opt for chromate treatment:
- Enhanced corrosion resistance. This is made possible with a thick, continuous coating that protects the metal surface. As a result, this enhances the base material does not get into contact with corrosive media.
- Improved aesthetics. It is possible to achieve a decorative appearance with chromate treatment. In addition, this provides a better base for liquid painting.
What is Chrome?
Chrome-plated parts are not made of 100% chrome but rather coated with a protective chrome layer. This surface finishing technique is called chrome plating. The procedure involves the application of chromium on another metal.
The primary purpose of chromium plating or chrome plating is to enhance the durability of parts by reducing wear and tear.
Ideally, chrome plating is a type of electroplating where dissolved metal ions create a protective layer on another metal. The process starts by getting rid of dirt, dust, and soil on the base metal. This is then followed by pre-treating the metal.
The main processes used in chrome plating are hexavalent chromium plating and trivalent chromium plating. The former is a conventional process mainly used for functional applications.
Benefits of Chrome Plating
Enhanced Aesthetics
Chrome plating can enhance the aesthetics of different metal parts. This explains why it is used on vehicle parts that include grilles and bumpers. In addition, it is used in household appliances to provide a polished appearance.
Improved Durability
Since chrome plating creates a layer of chromium on a metal surface, it protects the base material from wear and corrosion. As a result, chrome-plated parts can withstand damage.
Better Functionality
With chrome plating, you can enhance the functionality of a part. For instance, it is used on machine components and tools that require resistance to corrosion. Since chrome has reflective features, it is suitable for a range of applications.
Chromate Vs. Chrome – What are the Differences?
The common types of chrome plating are satin and bright. If you want a mirror-like finish, as is the case with toys, vehicles, and furniture, you should opt for bright chrome plating. This type of finish offers enhanced wear life, improved appearance, and increased protection against corrosion. On the other hand, satin chrome plating is similar to bright chrome but with a dull finish.
Chromate coating is done with or without zinc. When it comes to chromate with zinc, you have these types of finish: black, clear, and yellow. The coating is corrosion-resistant and provides the desired colors for the final part.
Alternatives and Substitutes
Some of the surface finishing processes that can substitute chrome and chromate finishes are: liquid painting, powder coating, anodizing, Alodine, and electroplating.
Deciding between chrome and chromate is not about which coating is superior but the most appropriate for your project. As discussed above, these coatings have advantages, properties, and disadvantages. There is a need to consider their pros and cons to make the right decision.