Our objective was to improve significantly corrosion protection of Cr(VI)-free surfaces in a swaged state.
Fig.: Swaged fittings after 300 hours salt spray testing (Test implemented by: Technical College South Westphalia / School for Technology and Business, Laboratory for Corrosion Protection)
There is no passivation that is able to achieve the positive characteristics of a Cr(VI) coating with its "self-healing effect." The basic layer of zinc is not suitable for mechanically stressed components, since it cannot offer the required level of corrosion protection with passivation and sealing.
To achieve a practice oriented level of corrosion protection, the basic layer must already be more resistant!
- Highest levels of corrosion resistance against red rust, even after handling and assembly.
- The zinc-nickel basic layer is many times more corrosion resistant than zinc.
- White rust appears only in form of a light grey haze. No "blooming" (voluminous white corrosion degradation product / zinc oxide).
- Demonstrably better corrosion resistance compared to the previous standard (A3C)
- Proven standard in the European automobile industry for many years
By converting to Δplus, you obtain a Cr(VI)-free alternative that meets the highest demands on corrosion resistance.
- White rust does not exist, since there is no "blooming" of zinc possible. There is only a light grey haze.
- Resistance to red rust (fitting): > 720 hours in unpressed state
- Resistance to red rust (socket): > 500 hours in swaged state
- The total layer thickness is 5 - 10 µm at a nickel content in the basic layer (ZnNi) of 12 %.
- Corrosion resistance against red rust (swaged) > 500 h
- Corrosion resistance against red rust (non-swaged) > 720 h
- Assembly behavior is not affected by the new surface finish Δplus, since the coefficient of friction, due to a special surface treatment, remains unchanged in comparison to yellow chromizing (A3C).
- Ecological compatibility conforms with EU Scrap Car Directive No. 2000/53/EG.
- Product color is transparent, silver.
- Paintable with commonly available enamels, however, painting test is recommended.
- Δplus is compatible with all commercially available hydraulic media.
- Allergy test according to DIN EN 1811 has been absolved. All limiting values were comfortably met.