Metallgesellschaft Aktiengesellschaft

Occidental Chemical Corporation

Oxy Metal Industries Corporation

Werner Rausch

Gerhard Muller

Dieter Hauffe

Horst Gehmecker

Peter Schubach

Gudrun Volling

Thomas Kolberg

Hardy Wietzoreck

Klaus Bittner

Thomas Wendel

Klaus Wittel

Georg Blumlhuber

Peter Jorns

Karl Lampatzer

Josef Rothkegel

Gerhard Mueller

Helmut Schumichen

Rainer Kuhna

Peter Mischke

Gisela Beege

Thomas Nitschke

Lothar Kaul

The invention is in a composition and process for the chromium free passivating postrinsing of conversion layers on metals before the application of a paint or adhesive. The conversion layers can be on the bases of phosphate layers, at least two polyvalent metal ions with complex formers, titanium, zirconium and/or hafnium. The postrinsing agent is an aqueous solution which has been adjusted to a pH value of up to 5 and which contains an aluminum fluorozirconate having an Al:Zr:F mole ratio of (0.15 to 8.0):1:(5 to 52), and in which solutions the total concentration of Al+Zr+F is 0.1 to 8.0 g/l. The postrinsing solutions may additionally contain at least one of the anions benzoate, caprylate, ethyl hexoate, salicylate in a total concentration of 0.05 to 0.5 g/1 and may preferably be adjusted to the required pH value with cations of volatile bases, such as ammonium, ethanolammonium and di- and triethanolammonium. The paint is subsequently applied suitably by cathodic electrocoating or powder coating or from a low-solvent high-solids paint. The rinsing treatment is over a period of 1 to 120 seconds at temperatures of 20.degree. to 80.degree. C. The invention is used as a pretreatment to the application of a paint coating, film coating or adhesive coating.

Process for a passivating postrinsing of conversion layers

In a process of phosphating metal surfaces phosphating solutions are employed which are substantially free of nickel and contain

Process for phosphating metal surfaces

Disclosed is a composition and a process of using the composition for phosphating a workpiece made of steel or partly galvanized steel in preparation for electro-immersion painting. The cleaned and rinsed workpiece is first activated with a weakly alkaline aqueous solution which contains titanium phosphate and is subsequently dipped into an acid aqueous phosphating solution at a temperature of from 40.degree. to 60.degree. C. which contains

Process of phosphating before electroimmersion painting

A process for forming phosphate coatings on metal surfaces is provided which comprises the steps of contacting said metal surface with an Fe(II)-containing phosphating solution comprising

Process of forming phosphate coatings on metal surfaces

Disclosed is a process for phosphating a galvanized surface, particularly of galvanized steel wherein the surface is contacted for up to 10 seconds with a phosphating solution which contains accelerator, particularly nitrate,

Phosphating process

A process for retarding the formation of incrustation on plant parts in contact with phosphating solutions in phosphating plants and where the working phosphating solution immediately after contacting the metal surface to be phosphated and while the solution is at its working temperature is caused to flow to contact an additionally presented solid surface that is disposed outside the region in which the workpiece metal surface and phosphating solution contact each other. The ratio of the second solid surface area which is contacted by the phosphating solution in the phosphating plant to the surface area of the plant parts in contact with the phosphating solution is at least 2. The solid surfaces preferably consist of metal, metal alloy, ceramics, porcelain, metal oxide, metal phosphate, such as phosphate bath sludge, and/or alkali fluoroaluminate and may be formed as planar and/or profiled plates, regularly or irregularly shaped bodies, spheres, fragments, particulate or finely particulate bulk material beds, wire, chips and/or nonwoven fabrics and may optionally constitute a fixed bed or fluidized bed.

Process of decreasing the incrustation in phosphating plants

A process to form phosphate coatings on individual parts of metal which at least on part of their surface consists of iron or steel. The individual parts are contacted at a temperature in the range of from 60 to 100 degrees centigrade for 3 to 30 seconds with an aqueous phosphating solution which contains 10 to 80 g/l zinc, 12 to 80 g/l phosphate (calculated as P.sub.2 O.sub.5), 40 to 150 g/l nitrate and, in addition 0.1 to 10 g/l fluoride, 0.01 to 10 g/l nickel, 0.0001 to 0.1 g/l copper, and may also contain tartaric acid, citric acid and/or manganese and in which the ratio of free acid to total acid has been adjusted to (0.1 to 0.3):1 and which contains at least 80 points of total acid and is virtually free of iron(II) ions. Prior to phosphating treatment, the individual parts may be cleaned and may optionally be treated to remove rust, scale and phosphate layers and/or be activated. After the phosphating treatment they may be passivated with an after-rinse solution. Each of said process steps is carried out for 3 to 30 seconds.

Process of forming phosphate coatings on metals

Disclosed is a process of producing a phosphate coating on a composite part consisting of steel and galvanized steel, which comprises alkaline cleaning, rinsing with an aqueous rinsing bath, and phosphatizing with an aqueous zinc phosphate solution. The formation of a non-uniform coating and of spots is avoided in the process of the invention by the use of a rinsing bath which contains at least 0.2 g/l alkali borate, at least 0.1 g/l alkali silicate and at least 0.05 g/l alkali nitrite, and which preferably contains said components in a total up to 5 g/l. If the composite part is to be activated with an activating bath which contains titanium phosphate before being contacted with the zinc phosphate solution, the activating bath must contain at least 1 g/l and preferably up to 4 g/l of tetraalkalipyrophosphate. The process of the invention can be used to prepare composite parts of steel and galvanized steel for subsequent painting, particularly by electrophoretic dip painting.

Process of producing phosphate coatings

Disclosed is a process of producing phosphate coatings on surfaces which consist of aluminum or its alloys and of at least one of the materials steel and galcanized steel by spraying or by spraying and dipping. Uniform phosphate layers having a high cover factor are obtained by the use of a phosphating solution which contains about 0.4 to about 0.8 g/l Zn, about 10 to about 20 g/l P.sub.2 O.sub.5, at least one accelerator and about 80 to about 220 mg/l fluoride ('F(el)'), as determined by a fluoride-sensitive electrode immersed into the bath solution and in which the content of free acid (FA) (in points) has been adjusted to and is maintained at a value corresponding to FA=(0.5 to 1.0)+K wherein K is calculated as K=(0.002 to 0.012).times.F(el). The free acid (FA) content is preferably adjusted to and maintained at FA=(0.04 to 0.06).times.C.sub.P.sbsb.2.sub.O.sbsb.5 +K and the content of free acid (FA) is determined using K=(0.003 to 0.009).times.F(el). The process is particularly suitable for preparing the surfaces for being painted, preferably by electrophoretic dip painting.

Process of producing phosphate coatings on metal surfaces

The quality of coatings in a low zinc phosphating process is improved by including an activator of formate, nitrilotriacetate, trichloroacetate or ethylenediamenetetraacetate to produce more uniform coatings particularly desirable in advance of electrocoating.

Process for phosphating metals

A process of electrodepositing zinc on steel wherein zinc-containing aqueous sulfuric acid electrolytes are used which contain one or more oxyacids of sulfur in which the sulfur has an oxidation number from +5 to +1. The phosphatizing of the resulting zinc coatings results in phosphate coatings which are virtually free of spots. Suitable oxyacids are sulfurous acid (H.sub.2 SO.sub.3), sulfoxylic acid (H.sub.2 SO.sub.2), hyposulfurous acid (H.sub.2 S.sub.2 O.sub.4) and/or thiosulfuric acid (H.sub.2 S.sub.2 O.sub.3) in the form of acids, salts and acid anhydrides. The oxyacids should be present in the electrolyte in a concentration of 0.05 to 10 g/l, preferably 0.1 to 2 g/l.

Method of electrodepositing zinc on steel prior to phosphating

A process for the phosphatizing of metals, particularly iron, steel and zinc, in which the metal is contacted with acidic aqueous zinc phosphate solutions, containing an oxidizing agent, which contain

Process for phosphatizing metals

A composition for the phosphatizing of metals, particularly iron and steel, which comprises an aqueous acidic, chlorate-containing zinc phosphate solution which contains

Composition and process for the phosphatizing of metals

A new composition and process provide improved phosphate treatment prior to cathodic electropainting. The surface is contacted with an aqueous acidic zinc phosphate solution having a weight ratio of Zn:PO.sub.4 of 1:12-110 and 0.3 to 2.0 g/l fluoborate prior to electropainting.

Phosphatizing prior to cathodic electropainting

An aqueous acidic composition free of hexavalent chromium is employed to treat a metal surface. The composition contains trivalent chromium, phosphate ion and dispersed silica.

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Oberursel, Germany

Werner Rausch