Atotech Deutschland Gmbh

Björn Dingwerth

Lukas Bedrnik

Heiko Brunner

Lars Kohlmann

Andreas Noack

Ellen Habig

Zdenek Starkbaum

Mike Krüger

Jaroslava Krizova

Vaclav Kriz

Jiri Kloubek

Kostantin Schwarz

Zdenek Sazanov

Kostantin Thom

The present invention relates to a process for corrosion protection of an iron-containing substrate wherein a first zinc-nickel alloy layer, a second zinc-nickel alloy layer and a black passivate layer are deposited onto the substrate. The nickel concentration in the second zinc-nickel alloy layer is higher than the nickel concentration in the first zinc-nickel alloy layer. The substrate surface obtained is homogenously black with an appealing decorative appearance and both resistance against white rust and red rust are improved.

Process for corrosion protection of iron containing materials

Additives for electrolyte baths for the electrodeposition of zinc or zinc alloy layer are described. The additives are polymers with terminal amino groups. These polymers are obtainable by reaction of at least one diamino compound (having two tertiary amino groups) with at least one di(pseudo)halogen compound, wherein the diamino compound is used in stoichiometric excess. The additives effect, in particular, a very little formation of bubbles and only few burnings as well as a uniform distribution of layer thickness in the electrodeposition of zinc or zinc alloy layers.

Polymers having terminal amino groups and use thereof as additives for zinc and zinc alloy electrodeposition baths

The invention relates to chromium- and cobalt-free treatment solutions for producing black coatings which afford corrosion protection. The treatment solution of the invention contains oxo cations or complex halogen ions or mixtures of oxo cations and complex halogen ions, an oxidant and an organic sulphur compound.

Treatment solution for producing chrome and cobalt-free black conversion coatings

The invention relates to a treatment solution for producing substantially chromium(VI) free black conversion layers on alloy layers containing zinc, the solution comprising the following: (i) at least one first carboxylic acid having 1 to 8 carbon atoms, the acid containing no polar groups with exception of the carboxyl group and being a monocarboxylic acid, (ii) at least one second carboxylic acid having 1 to 8 carbon atoms, comprising at least one further polar group that is selected from &#x2014;OH, &#x2014;SOH, &#x2014;NH, &#x2014;NHR, &#x2014;NR, &#x2014;NR, and &#x2014;COOH (wherein R is a C-Calkyl group), (iii) 20 to 400 mmol/l Crand (iv) 50 to 2000 mmol/l NO. The invention further provides a method for the black passivation of surfaces containing zinc, wherein the surface to be treated is immersed into such a treatment solution.

Chromium(VI)-free black passivation of surfaces containing zinc

The invention relates to a method for producing a coating layer protecting against corrosion wherein a surface which is to be treated is brought into contact with an aqueous treatment solution containing chromium(III) ions and at least one phosphate compound, wherein the ratio of the molar concentration of the chromium(III) ions to the molar concentration of the at least one phosphate compound (calculated as orthophosphate) lies between 1:1.5 and 1:3. The method improves the corrosion protection of metallic, in particular, zinc-containing, surfaces provided with conversion layers. The decorative and functional properties of the surface are maintained or improved. Furthermore, the known problems resulting from the use of chromium(VI)-containing compounds or from post-treatments with polymer dispersions are avoided.

Anti-corrosion treatment for conversion layers

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Berlin, Germany

Björn Dingwerth