Modern coatings for light metals involve highly specialized processes that have to fulfill many different requirements. In addition to high-performance corrosion protection, the use of environmentally sound production methods is playing an increasingly important role for metal-processing businesses. As a specialist in surface treatments, Henkel is setting industry-wide benchmarks with its broad product portfolio.
Alodine 400 - Chrome-Free Coating without Compromising on QualityWith its chrome-free Alodine 400 process, Henkel offers a method for pretreating aluminum surfaces that not only enhances environmental performance and occupational health and safety, but also meets high-quality standards in terms of paint adhesion and corrosion resistance of powder-coated materials. By using this technology, which is exempt from hazard labeling, companies gain the advantage of being able to dispense entirely with classic wastewater treatment, as the process is totally free of heavy metals. At the same time, line operators benefit from enhanced occupational health and safety.
Experience from the field confirms the high quality of the chrome-free process. On the metal surface it generates a transparent, titanium-based conversion coating that provides long-term corrosion protection for powder-coated parts and, acting as an adhesion promoter, also improves subsequent paint application. The advanced Alodine 400 conversion process is GSB and Qualicoat approved, thus offering the best preconditions for a long-term weather-resistant powder coating.
Alodine 5992 - Corrosion Protection for Non-Painted SurfacesAnother new development in metal pretreatment is Alodine 5992. Unlike passivation techniques containing toxic chromium(VI), the conversion coating generated with this process is based on non-toxic chromium(III) compounds. In view of the many regulatory requirements – such as compliance with the RoHS, WEE and ELV directives – Alodine 5992 thus constitutes a genuine alternative to traditional conversion treatments. The trivalent coating offers the same high quality of bare-metal corrosion protection for unpainted aluminum surfaces, as well as providing an optimal substrate for painting; powder-coated aluminum parts have the same level of corrosion protection as yellow-chromated sheets and profiles. Alodine 5992 is Qualicoat certified and also satisfies MIL requirements for use in the aircraft industry. Moreover, the use of this process simplifies wastewater treatment and disposal, as there is no need for hexavalent to trivalent chromium reduction.
Alodine EC2 - a Multifunctional, Robust CoatingChrome-free Alodine EC² technology provides protection against heavy stressing in extreme climate zones or in harsh industrial environments. Alodine EC² coatings withstand the most severe loading. They are impervious to heat, cold, salt, gas, oil and water. Combining resistance to chemicals with high temperature resistance, hardness and abrasion resistance, Alodine EC² is suitable for many demanding industrial applications under extreme conditions – from the intense heat and high pressures in automobile engines through to the galvanic corrosion of ships’ components by seawater.
The electro-ceramic coating is also so flexible that the treated components can be subsequently shaped without any damage to the Alodine EC² layer. Furthermore, the coating can be painted, enameled, bonded or covered with any other kind of coating. Unlike conventional processes, a decorative paint finish can be applied without the need for a primer. And, since no additional process steps are required, this technology makes the entire manufacturing process shorter and more resource-efficient.