The invention relates to a method for producing a silane-modified silicate. In order to obtain optimal corrosion protection properties, a silane compound according to the invention is at least partially hydrolyzed and/or condensed in the presence of a silicate compound at a pH value greater than or equal to 8 and then a pH value less than or equal to 7 is set by adding acid. The invention further relates to an aqueous acidic passivation composition for metal substrate coated with the passivation composition.

A method and apparatus for processing an object (4), for example an aluminium aircraft part, the method comprising: performing a first conversion coating process to dispose a first conversion coating (10) onto at least part of a surface of the object (4); partially masking the first conversion coating (10) disposed on the object (4); performing an etching process to remove, from the object (4), an unmasked portion of the first conversion coating (10) while retaining the masked portion of the first conversion coating (10) on the object (4); and performing a second conversion coating process to dispose a second conversion coating (12) onto a region of the surface of the object (4) from which the unmasked portion of the first conversion coating (10) was removed. A paint layer (14) may then be applied to, e.g., the second conversion coating (12).

Disclosed herein is a phosphonate-free, aqueous pickling composition having a pH value at 55° C. in the range from 5 to 9, and containing at least one copolymer, which is water-soluble or water-dispersible and selected from the group consisting of polyvinylpyrrolidones; the content of water being in the range from 95.0 wt.-% to 99.9 wt.-% based on the total weight of the composition. Further disclosed herein is a concentrate to produce such compositions, a pickling method for pickling metallic substrates making use of the compositions, a coating method for coating metallic substrates including the pickling method and a method of using the compositions for pickling metallic substrates.

Disclosed herein is a phosphonate-free, aqueous pickling composition having a pH value at 55° C. in the range from 5 to 9, and containing at least one copolymer, which is water-soluble or water-dispersible and selected from the group consisting of polyvinylpyrrolidones; the content of water being in the range from 95.0 wt.-% to 99.9 wt.-% based on the total weight of the composition. Further disclosed herein is a concentrate to produce such compositions, a pickling method for pickling metallic substrates making use of the compositions, a coating method for coating metallic substrates including the pickling method and a method of using the compositions for pickling metallic substrates.

The invention relates to an aluminum alloy strip with improved surface optics, which is fabricated via hot and/or cold rolling, and consists of a type AA 3xxx, AA 5xxx, AA 6xxx or AA 8xxx aluminum alloy. The object of proposing an aluminum alloy strip that is suitable for attractive and precious surface optics despite the elevated percentage of alloy constituents is achieved in that, after degreasing, the finish-rolled aluminum alloy strip exhibits an increase in the luminance value L*(ΔL) in relation to the rolled-greasy state of more than 5 while measuring the color of the surface in the CIE L*a*b* color space using a standard illuminant D65 and a normal observation angle of 10°, excluding direct reflection in 45°/0° geometry.

The invention relates to an aluminum alloy strip with improved surface optics, which is fabricated via hot and/or cold rolling, and consists of a type AA 3xxx, AA 5xxx, AA 6xxx or AA 8xxx aluminum alloy. The object of proposing an aluminum alloy strip that is suitable for attractive and precious surface optics despite the elevated percentage of alloy constituents is achieved in that, after degreasing, the finish-rolled aluminum alloy strip exhibits an increase in the luminance value L*(ΔL) in relation to the rolled-greasy state of more than 5 while measuring the color of the surface in the CIE L*a*b* color space using a standard illuminant D65 and a normal observation angle of 10°, excluding direct reflection in 45°/0° geometry.

A kit for applying a coating includes a first handheld container with a first liquid trivalent chromium salt composition disposed therein. A first applicator is disposed in fluid communication with the first container and is configured to dispense the first composition. The kit also includes a second handheld container having a second liquid oxidizing agent composition disposed therein. A second applicator is disposed in fluid communication with the second container and is configured to dispense the second composition.

A kit for applying a coating includes a first handheld container with a first liquid trivalent chromium salt composition disposed therein. A first applicator is disposed in fluid communication with the first container and is configured to dispense the first composition. The kit also includes a second handheld container having a second liquid oxidizing agent composition disposed therein. A second applicator is disposed in fluid communication with the second container and is configured to dispense the second composition.

Provided herein is a method for pretreating aluminum materials, particularly aluminum wheels, wherein an aluminum material is successively i) cleaned and subsequently rinsed, ii) optionally subjected to alkaline pickling and subsequently rinsed, iii) optionally contacted with an aqueous composition comprising at least one mineral acid, iv) optionally rinsed and v) contacted with an acidic aqueous composition comprising a) at least one compound selected from the group consisting of titanium, zirconium and hafnium compounds and b) at least one linear terpolymer prepared by controlled radical polymerisation and comprising vinylphosphonic acid monomeric units, hydroxylethyl- and/or hydroxylpropyl-(meth)acrylate monomeric units and (meth)acrylic acid monomeric units, vi) optionally rinsed, vii) optionally contacted with another aqueous composition, viii) optionally rinsed and ix) optionally dried. Further provided herein is a corresponding composition as well as the use of the materials treated according to the method.

A steel sheet coated with a zinc-based coating layer having a reaction layer on the surface of the steel sheet is manufactured by a method that includes bringing a steel sheet coated with a zinc-based coating layer into contact for 1.0 second or more with an alkaline aqueous solution containing one or more chelating agents selected from among sodium gluconate, sodium glucoheptonate, sodium citrate, tartaric acid, arabonic acid, galactonic acid, sorbit, mannite, glycerin, EDTA, and sodium tripolyphosphate in a total amount of 0.050 mass % or more and having a pH of 10.0 or more as a pre-treatment before a formation of the reaction layer, and forming the reaction layer being an oxide layer containing a crystal-structured substance expressed by Zn.sub.4(SO.sub.4).sub.1-X(CO.sub.3).sub.X(OH).sub.6.nH.sub.2O.