Pyrene Chemical Services Limited

Parker Chemical Company

Brent Chemicals International Plc

George L Higgins

Jane Cable

An alkaline aqueous solution comprising hexavalent chromium, trivalent chromium, and a complexing agent for trivalent chromium sufficiently effective to solubilize at least 20 ppm of trivalent chromium forms a protective coating when contacted with zinc, aluminum, and particularly zinc-aluminum alloys.

Composition and process for treating metal surfaces

An improved composition and process for forming a corrosion-resistant complex oxide coating on a zinc or zinc alloy surface incorporates in an aqueous alkaline composition of pH value greater than 11 at least three complexed polyvalent metals, one of which is trivalent chromium.

Process and composition for conversion coating metal surfaces

An aqueous wet blasting composition and process for cleaning a ferrous surface which reduces the rusting of the surface due to aqueous contact by incorporating phosphate ions and an imine compound in the composition.

Processes and compositions for abrasive blast cleaning

A composition and method are particularly suitable for applying a corrosion preventive and paint receptive coating to metal surfaces where immersing treatment is impossible or impractical. A brush-on aqueous composition free of reducing agent containing hexavalent and trivalent chromium and at least 5 g/l of silica or silicate together with an organic solvent and thickening agent is applied to the metal surface and dried.

Chromate coatings for metals

A composition for forming paint-base coatings on aluminum comprising an aqueous solution having a pH of from about 9 to about 12.5 and containing an effective coating forming amount of a complexing agent which has at least one of a nitrogen atom with a lone pair of electrons and a carboxylate group, which solution is substantially free of components which inhibit the coating formation. Aluminum surfaces are treated with the this solution to form a paint-base coating having a thickness of at least about 0.05 g/m.sup.2 and, thereafter, a paint or similar siccative coating is applied to the surface without the prior application of chromate or other conventional paint-base coating forming materials.

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Windsor, United Kingdom

George L Higgins