GEOMET®
04/04/2011
GEOMET® zinc flake technology opens new horizons for corrosion protection
Large R&D resources in NOF Metal Coatings Europe (previously Dacral) have been allocated in the recent years to the development of the range of GEOMET® applications. These developments open new possibilities of industrial applications in the field of protection against corrosion. Examples are high performing black coatings and coatings lasting the required life on chassis components. In the same time, R&D succeded in developing production routes for the GEOMET® chemicals, that allow the VOC content of these water-based products to be reduced substantially.
High performing black coatings
Black corrosion protective coatings for threaded parts and other metal components are requested for design reasons by the automotive industry as well as in other industrial fields. NOF METAL COATINGS GROUP, a specialist in thin corrosion protective coating materials, offers two families of black coatings:
- GEOBLACK® ML and GEOBLACK® 500M obtained by addition to the GEOMET® basecoat a PLUS® Black topcoat
- GEOBLACK® KT, a new development with basecoat GEOMET® and topcoat GEOKOTE® Black. This topcoat ensures a high resistance against all chemicals including strong acids and solvents.
All black coatings are chromium-free, water-based, and offer a high corrosion resistance: 1000 hours NSS (Neutral Salt Spray Test) without red rust (Fe corrosion) or white rust (Zn corrosion). Outdoor weathering tests and vehicle tests have shown a corrosion resistance performance that matches the current expectations for chassis parts in the automotive industry.
Life-resistant coatings for chassis components
In order to obtain a life lasting zinc-based coating on chassis components in the automotive industry, it is necessary to apply a sufficient thickness of coating material. Depending on the application, a range of 15 µm to 30 µm will give the appropriate protection. As the usual thickness of GEOMET® for bulk parts is 6 to 10 µm, ways for increasing the thickness had to be studied.
A specific product, GEOMET® 900, has been developed, which enables the application of 15 µm to 30 µm in 1 or 2 coats. The product development has been completed together with the application process development. After alkaline degreasing and without phosphating, the components are dipped in the GEOMET® tank and draw out at a controlled speed. As the product is non-drip and non-sag, the drying and curing cycle can start immediately.
Practical trials over 2 years and with components of various types and shapes have proved the potential of this development. Fuel filler tubes for instance can be coated with 1 coat of GEOMET® 900 by this process, a black top-coat can be sprayed on the outside part for the colour requirement and for additional protection.
More information at: infofr@nofmetalcoatings.com
