Coatings 101:
Unlocking the Secrets of Strong Coatings


You might not realize it, but the surfaces of solid materials are never perfectly smooth. They’re more like a challenging maze of peaks and valleys, often referred to as the “surface profile” in the world of coatings. These peaks and valleys include tiny pores, holes, crevices, and micro-voids on the substrate. According to the mechanical theory of adhesion, to function properly a coating must penetrate the irregularities on the surface, displace the trapped air at the interface, and lock-on mechanically to the substrate.

How it Applies:

When we apply a coating, like the ones we develop at Phoenix Protective Coatings, we want it to do more than just sit on the surface. We need it to penetrate all those nooks and crannies, push out trapped air, and securely bond to the substrate. This bond is crucial for the coating’s success. In these applications the formation of covalent chemical bonds occurs across the interface. These strong and durable bonds are generally the result of close contact or adsorption of the adhesive on the surface followed by a chemical reaction.

To make this happen, some coatings are engineered with special additives. These additives have functional groups that can chemically bond to the substrate underneath. This results in strong and durable bonds. It’s like finding the perfect combination lock and key, ensuring a strong connection.

Metal surface with micro peaks and valleys

Above: Example of a really rough surface profile.

Creating the Strongest Bonds:

Certain coatings also contain chemical groups that love to connect with similar groups on the substrate. It’s a bit like piecing together a complex puzzle where the right fit creates a powerful bond. That’s why our coatings are developed with these chemical additives, to create a superior bond.

Now, here’s where things get even more fascinating. We use what are called adhesion promoters or coupling agents. Think of them as the bridge builders of the coating world. They connect the coating to the substrate. One end of the adhesion promoter molecule has functionality that will react with the coating, and the other end has a functionality that will react with the substrate. A strong and durable bond forms as the coating cures.

Take silanes, for instance. They’re like the superheroes of adhesion promoters. We use chemicals like them as additives in many of our coating formulations. They enhance adhesion, resist moisture, and help prevent corrosion.

But there’s a catch. If the surface is dirty or contaminated, it’s like trying to stick masking tape a to dusty surface, and the coating won’t create an optimal mechanical bond to the substrate. Contamination that comes between the coating and the substrate surface can weaken the intermolecular electrostatic forces and interfere with mechanical interlocking, among other things.

To ensure our coatings perform at their best, we emphasize the importance of keeping the surface incredibly clean before application. Cleanliness is one of the keys to a solid bond between the coating and the substrate.

Below: Close-up of a spray applied monolithic coating

Spray applied monolithic coating

Take silanes, for instance. They’re like the superheroes of adhesion promoters. We use chemicals like them as additives in many of our coating formulations. They enhance adhesion, resist moisture, and help prevent corrosion.

Unlocking the Key:

Finding the right balance between the specific formulation, application parameters, and surface preparation is an art and a science. Here at Phoenix, we strive to make it as easy as possible to find that balance for our applicators.


In summary, here at Phoenix Protective Coatings we create coatings that aren’t just superficial layers; they’re engineered to dive into the microscopic landscape of surfaces, forming strong chemical and mechanical bonds. We build bridges between coatings and materials for long-lasting protection. However, all these efforts can be in vain if the surface isn’t clean. So, the realities are that the cleanliness of the surface, as well as the formulation of your coating, are both critical to the success of coating adhesion.

Choosing Phoenix is what ensures your coatings are not just strong, but Phoenix-strong.

If you’re in search of great deals on protective coating supplies, you know we’ve got them.  Phoenix Protective Coatings is your industrial coating supplier, and we pride ourselves on listening to customers and providing you with top-tier technical knowledge and support. Explore our broad range of products and contact our expert team for additional information today.

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