Dacromet vs Zinc Flake: What’s the Difference?

Dacromet, known by the same name in English, is one of the surface treatment methods for metals—particularly for bolts and nuts—and is used to increase the service life of steel components.

In this article, we’ll provide a detailed explanation of Dacromet vs Zinc Flake coating. Stay with us.

What is Dacromet?

Dacromet is a water-based lamellar coating composed of fine particles of zinc, aluminum, chromium trioxide (CrO₃), chromium oxide (Cr₂O₃), PTFE (Teflon-like substances), and modified chromates (mCrO₃ and mCr₂O₃).

It’s important to note that some of these materials, such as PTFE and modified chromates, are insoluble in water and act as binders to hold zinc and aluminum particles together to form the coating layers.

From Chinese Dacromet to Original Dacromet

Originally, Dacromet was developed in the United States in the 1970s as a high-performance anti-corrosion coating by companies like Metal Coatings International (MCI) and Dacral, which later became part of NOF Metal Coatings Group. Once introduced to the market, its exceptional corrosion resistance quickly gained attention and widespread adoption.

As Dacromet coating gained global popularity, Chinese manufacturers attempted to replicate this unique formulation and launched similar-looking products. However, these imitations never matched the quality of the original and eventually failed in the market.

In Iran, the spread of low-quality Chinese Dacromet led to a damaged reputation of the Dacromet name, as the counterfeit version replaced the original product and failed to deliver effective protection.

Chinese producers were unable to reverse-engineer the exact formulation of European Dacromet and failed to achieve the desired performance levels. As a result, these versions were rejected by the market.

In response, the original manufacturer, NOF Metal Coatings Group (a Japanese company), rebranded their product to Zinc Flake Coating to avoid the negative perception associated with the Dacromet name in Iran.

Today’s high-quality coatings sold under the name Zinc Flake are still produced by the same original company (NOF), using the same base materials and process as Dacromet.

Dacromet vs Zinc Flake: What’s the Difference?

As explained earlier, Dacromet and Zinc Flake are essentially the same product from the same company, developed using the same materials and for the same purpose: corrosion protection of steel parts.

Zinc Flake is the updated brand name of Dacromet, manufactured under the license of NOF Metal Coatings. NOF is the world’s largest producer of Zinc Flake coating materials and supports numerous production lines and distributors across five continents.

Notably, automotive manufacturers across Europe are required to use Zinc Flake coatings to protect metal parts in vehicles against corrosion.

In terms of application, formulation, and performance, there is no technical difference between Dacromet and Zinc Flake.

Dacromet (Zinc Flake) Coating Process

Dacromet is applied using three primary methods, depending on the part size, design, and quality requirements:

1. Dip-Spin Method

Used for small-sized components like springs, bolts, and nuts. After surface preparation, parts are immersed in Dacromet solution and spun to remove excess material. They are then baked in an oven to cure the coating.

2. Spray Method

As the name suggests, the coating is sprayed directly onto the metal surface, followed by baking in a curing oven.

3. Dip-Drain Method

Used for larger steel components. Parts are suspended and dipped into the Dacromet solution, then allowed to drain before being baked.

Industrial Applications of Dacromet (Zinc Flake)

Industries that commonly use Dacromet/Zinc Flake coatings include:

• Automotive Manufacturing: For parts such as pipes, springs, bolts, clamps, and stamped components.
• Marine Industry: For engine parts, piping systems, fasteners, and chains exposed to salty environments.
• Rail Industry: Suitable for both small and large railway components.
• Agriculture: For fasteners and steel parts exposed to moisture, such as bolts, nuts, clamps, and pipes.
• Power Plants: For hardware, fittings, and small components like nuts.
• Construction: Widely used for fasteners, nails, screws, and structural connections.
• Petrochemical Industry: Ideal for a variety of equipment and exposed metal components.

Advantages and Disadvantages of Dacromet Coating

Advantages

• Excellent Corrosion and Heat Resistance

More durable than traditional coatings such as electro-galvanizing, hot-dip galvanizing, or zinc-nickel plating.

• No Hydrogen Embrittlement

Since no acid is used during processing, the risk of hydrogen embrittlement is eliminated.

• Environmentally Friendly

No toxic waste or harmful emissions. Some variants are also chrome-free, making them suitable for food, medical, and hygiene industries.

• Thin but Durable Coating

Offers high protection with a thickness of around 10 microns.

• No Porosity or Voids

Thanks to the spin stage, all pores and gaps are filled uniformly.

No Mechanical Deformation: Applied at low baking temperatures, preserving the mechanical properties of the base part.

Disadvantage

The main challenge is the residual negative perception due to the previous spread of low-quality Chinese imitations. However, with increasing awareness of the true quality and performance of Zinc Flake coatings, Dacromet is regaining its position in the market.

Dacromet Standard Specification

According to ASTM-F1137-11, this standard covers corrosion-resistant coatings for fasteners and includes four coating grades (A, B, C, and D).

• Grade A: Zinc phosphate coating without additional sealants.
• Grade B: Zinc phosphate coating with a dry organic sealant.

This standard is applicable to fasteners such as washers, clips, nuts, and other steel components requiring corrosion protection. These coatings may also be used for decorative purposes.

Conclusion

In this article, we introduced Dacromet as one of the best anti-corrosion and anti-rust coatings, explained its coating process, applications, and pros and cons. As mentioned, Zinc Flake is the rebranded version of Dacromet, licensed by NOF company, and there is no difference between the two in terms of material, application method, or performance.