The dacrotized process will end in September 2022.


Working scene of surface treatment dacrotized

Provides a surface treatment that exhibits an excellent anti-corrosion property while preventing hydrogen embrittlement.

  • Hexavalent chromium
  • Corrosion resistance

DACROTIZED® treatment is an anti-corrosion system that has been patented around the world.
DACROTIZED® treatment, which is an anti-corrosion technology that goes beyond the conventional sense about surface treatments and electrogalvanizing, combines metallic zinc with hexavalent chromium to form a silver-white film with high corrosion resistance.
Especially in the treatment process, there is no fear of pollution, and it is a new technology that meets the needs of the age with excellent features.
Currently, it is widely used in a wide range of fields, including the civil engineering and construction industries around the world.

Mechanism of DACROTIZED®

Mechanism of DACROTIZED

The treatment solution (DACRODIP) used for the DACROTIZED® treatment is a dispersed aqueous solution of metal zinc flakes, chromic anhydride, and glycol. The treatment object is dipped into the DACRODIP solution and heated to about 300°C in a baking furnace so that hexavalent chromium is reduced by organic substances, such as glycol, to produce water-insoluble amorphous nCrO3 and mCr203, which acts as a binder to form a film by interconnecting zinc flakes laminated in several tens of layers. At the same time, chromic anhydride in the DACRODIP solution oxidizes the metal matrix surface to form a chemical bond, creating a strong adhesive force. The anti-corrosion mechanism of the DACROTIZED® treated coating is composed of the zinc particle-controlled self-sacrifice protective effect, the immobilization of the base surface by chromic acid, and the barrier action of zinc flake and chromium compound. It demonstrates excellent corrosion resistance unlike other coatings.

Eight features of DACROTIZED®


Offers excellent resistance to salt spray and cycle testing.

Having far superior corrosion resistance in salt spray tests compared to conventional electrogalvanizing, with a thickness of only about 8 to 10 μm.


Offers excellent heat and corrosion resistance.

Having higher heat and corrosion resistance in heat resistance tests compared to conventional electrogalvanizing.


Prevents galvanic corrosion (contact corrosion between different metals) with aluminum.

Minimizes galvanic corrosion (contact corrosion between different metals) in combination of aluminum and iron compared to electrogalvanizing.


There is no fear of hydrogen embrittlement.

Since no pickling process and electrolytic reaction are involved during the treatment, there is no risk of hydrogen embrittlement during the treatment process.


Offers excellent attaching property.

It can also be applied to complex shapes that are difficult to process with conventional electroplating.


Other coating can be applied on DACROTIZED® processed surface.

Coloring is possible with appropriate paint. Excellent in adhesion with paint compared to electrogalvanizing.


Processable for various metals.

DACROTIZED® treatment can be applied to copper, castings, sintered materials, aluminum die castings, and stainless steel. Especially suitable for aluminum rust prevention.


There is no concern about pollution.

Unlike electrogalvanizing, no water washing is involved in the process. Furthermore, the volatile matter in the baking process is mainly water. There is, therefore, no concern about wastewater and air pollution.

DACROTIZED® Applications

Used in a variety of fields, both in Japan and overseas.

  • Civil engineering parts
  • Building parts

Switching from DACROTIZED® to GEOMET® has been promoted from the consideration of an environment.

DACROTIZED® is a surface treatment with excellent rust prevention. It, however, uses hexavalent chromium and does not comply with the RoHS Directives and REACH Regulations.Therefore, we are in the process of switching to GEOMET®, which was developed based on the DACROTIZED® technology.
We can offer GEOMET® as an alternative to DACROTIZED® (non-chromium) and PLUS Series JL Black (PLUS processing) as an alternative to Black DACRO (liquid production discontinued).

  • Hexavalent chromium
  • Non-chromium

Contact the following for consultations and inquiries about DACROTIZED®

We propose the optimal surface treatment for you.
Please feel free to contact us.

  • 1We have the know-how and experience to propose the optimal combination of surface treatments according to the operating environment, corrosion resistance, and cost.
  • 2We offer a wide range of lineups for foundations, base coats, and top coats to meet your needs.

Responsible personnel:Yoshida


Kadoma Plant
26-3 Yanagidacho, Kadoma-shi, Osaka 571-0038 Japan


Contact the following for consultations and inquiries about DACROTIZED®.

*DACROTIZED® and GEOMET® are registered trademarks of NOF Metal Coatings Co., Ltd. (formerly Nippon Dacro Shamrock Co., Ltd.)