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 download the product sheet
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GEOMET® 500
GEOMET®500 is a non-electrolytically applied thin-film coating of metallic grey colour with integral lubrication for the corrosion protection of parts made from steel, cast iron, or other iron metals.
GEOMET®500 is composed of zinc and aluminium flakes in an inorganic binder; it has been developed by DACRAL S.A., the producer of DACROMET®500, as the chromium-free alternative.
The GEOMET®500 coating is obtained by the application of an aqueous dispersion by cold immersion or spraying and is therefore free of any risk of hydrogen embrittlement. |
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CHARACTERISTICS
GEOMET®500 is a sacrificial coating. Its corrosion resistance depends upon the thickness of the coating and is due to the combination of several mechanisms:
• barrier effect due to the tile-like structure of the film,
• controlled sacrificial protection of the zinc in relation to the metal substrate,
• the integral film passivation, which reduces the speed at which the zinc and aluminium are consumed.
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COATING THICKNESS
GEOMET®500: grade A > 24 g/m² (coating weight); 6-8 µm(a) (thickness); >600 Hours without red rust > 200 hours without white rust. (salt spray test: ISO 9227)
GEOMET®500: grade B > 36 g/m² (coating weight); 8-10 µm(a)(thickness); >1000 Hours without red rust >200 hours without white rust. (salt spray test: ISO 9227)
(a) The indicated thickness is a mean value (see ISO 10683 or ISO 13858). Individual measuring points are not significant, especially for parts coated in bulk.
COEFFICIENT OF FRICTION :
The coating includes the lubricant PTFE throughout its thickness. A controlled coefficient of friction is obtained with this product.
GEOMET®500 : 0,12 ≤ µ mean ≤0,18 (ISO 16047)
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PROPERTIES
1. NO HYDROGEN EMBRITTLEMENT: when surface preparation is done according to recommended techniques, the non-electrolytic application of the film does not induce hydrogen embrittlement. GEOMET®500 is therefore especially indicated for protecting safety parts.
2. RESISTANCE TO AUTOMOTIVE FLUIDS: GEOMET®500 tested according to VDA 621-412 provides a satisfactory resistance to standardised test fuel, diesel fuel, motor oil, organic solvents, cooling fluid, brake fluid. The coating also resists to an immersion for 24 hours in brake fluid at 20 °C.
3. DUCTILITY: sufficient for elastic deformations of springs, clips…
4. ELECTRICAL CONDUCTIVITY: GEOMET®500 has a sufficient conductivity for all the applications.
5. HEAT RESISTANCE: GEOMET®500 keeps its mechanical properties up to 300 °C, which is the temperature needed for the binder formation. For applications above 300 °C, specific tests are necessary.
Its resistance to salt spray test exposure is not modified by a prior exposition of the coated parts for 100 hours at 180 °C.
6. PAINTABILITY: GEOMET®500 may be covered by most organic coatings. Due to the laminar structure of the coating, the cross-hatched adhesion test is not adapted.
7. THROWING POWER: the application on parts by cold immersion allows for the total covering of the internal surfaces, for example screws with captive washers, clips, tubes.
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APPLICATION FIELD
GEOMET®500 may be used in all industrial areas for the protection of ferrous metals by appropriately selected application techniques. It is especially suited to fasteners. In the automotive and truck industry, OEM specifications must be respected. In industries with no specific standard, ISO 10683 and ISO 13858 can be used. The standards describe requirements for zinc-flake coatings. Related information can be found on the website www.dacral.com.
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HOMOLOGATIONS
GEOMET® 500 is a chromium free corrosion protective coating made from water-based chemicals free of harmful substance. It meets the requirements of the European legislation on recycling, especially the directives 2000/53/EC and 2002/95/EC. The water-based dispersion used to obtain the coating helps to comply with the current legislation on gas emissions.
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APPLICATION
Industrial application of GEOMET®500 is carried out on existing DACROMET® lines. This consists of applying a wet film of GEOMET®500 by cold immersion or spraying, followed by curing at 300°C.
Several application techniques are recommended by DACRAL S.A.:
• Dip-spin in bulk:
the parts are cleaned, immersed in baskets into the GEOMET® bath and spun to eliminate excess material. The wet film is then dried and cured at a temperature of 300 °C, which is necessary to build the binder.
• Spraying for bulk parts:
the parts are cleaned, and then loaded into a special spray installation. The technology is well adapted for nuts and for small screws with internal drive. No build-up can occur.
• Dip-drain-spin on racks:
the parts are attached to racks. The following procedure is the same as for bulk applications.
• Pneumatic or electrostatic spray:
for parts which require only exterior protection.
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