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Surface Coating Options Part Four – Additional Options


In this last post about surface coating, I will focus on coating options that are available but do not fit into one of the three categories that I previously discussed.

Chem Film

This coating is used for Aluminium die casting. It is also commonly known as conversion coating. The Colour of chem film can vary from a dark golden brown to a light yellow tint, depending on several variables. It produces a film that has no dimensional change to the Aluminium part. There are two types of chem film: class 1A and class III. These classes are described in more detail on the surface finishing page of our website.

Black E-Coat

Black E-coat is a paint coating that is electrically applied. This coating is used to enhance the appearance of a part as well as protect the surface of a part.


There are two types of commonly used anodizing coats – clear and black. Anodizing creates a non-conductive, protective coating that seals the part. The final Colour of an anodized part will depend on the alloy used for die casting. Aluminium will show almost no Colour change, which is why this is the most widely used alloy to be anodized. During the anodizing process, the part can be dyed a variety of Colours. Black, blue, and red are the three most popular Colours used. There are two classes of anodized parts, class 1 and class 2. Class 1 is not dyed and is the natural Colour. Class 2 is dyed and a Colour must be specified.

Polyurethane Paint

This type of paint offers excellent durability and for this reason, it is often recommended for parts that will be used outside or exposed to the elements. Polyurethane paint can be applied as either a smooth or textured coating, and is typically air-dried but can also be baked to speed up the drying process. 

Powder Coating

Powder coating results in more uniform thickness and more consistent Colour than standard wet paints. During the coating process, the part is cured at higher temperatures, which ensure tougher finishes. Not only does the coating have high hardness but it is also used because it’s visually appealing, conceals minor surface flaws and is a durable high gloss. This coating is also environmentally friendly – it has no air quality hazards or hazardous waste.

Black Oxide

The final process is black oxide, which provides a protective, corrosion resistant finish. The most commonly used application for this coating is for firearms, but other applications include spark plugs, furniture brackets, and mower blades. The black finish does not chip and acts as an absorbent to hold oils or wax. The coating is economical and extends the service life and performance characteristics of a part.

In these past four blog posts, we’ve discussed chrome, nickel, other elements, and additional coating options that are not elements.

Do you have any questions about the surface coatings we’ve reviewed? Are there additional surface coatings that you’d like to see? If so, please reach out to our engineering team. We would be happy to answer any additional questions you have or provide assistance for your project. 

You may also be interested in:

Surface Coating Options Part One - Chrome & Chromate

Surface Coating Options Part Two – Nickel

Surface Coating Options Part Three – The Elements



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Last updated 03.22.2021