Abstract: A multistage method for treatment of composite metal structures containing metallic surfaces of aluminum, zinc and optionally iron, is provide wherein in a first step, selective zinc phosphating of zinc and ferrous surfaces proceeds using a phosphating solution containing a quantity of water-soluble inorganic silicon compounds sufficient to suppress white spot formation on zinc, but less than the quantity where zinc phosphating loses selectivity. In a following second step, aluminum surfaces are passivated with an acidic treatment solution. Also provided is a zinc phosphating solution suitable for said method containing at least 0.025 g/l, but less than 1 g/l of silicon as water-soluble inorganic compounds calculated as SiF6, wherein the product (Si/mM)·(F/mM) of the concentration of silicon [Si in mM] in the form of water-soluble inorganic compounds and the concentration of free fluoride [F in mM] divided by the free acid point number is no greater than 5.

Abstract: The present invention relates to the field of phosphating for corrosion-protective pretreatment of zinc surfaces, being directed toward the use of largely nickel- and cobalt-free zinc phosphating solutions. The present invention makes available an alternative to trication zinc phosphating, in which the zinc surfaces of a component are firstly, before zinc phosphating, passivated with an alkaline composition containing iron(III) ions, and thereby preconditioned for a largely nickel- and cobalt-free zinc phosphating operation. In a further aspect, the invention relates to a component, in particular an automobile body, that comprises at least in part surfaces made of zinc, the zinc surfaces being covered by a two-layer system made up of a first, inner passive layer containing iron and resting on the zinc surface, and a second, outer crystalline zinc phosphate layer resting on the inner layer.

Abstract: The present invention relates to an aqueous alkaline composition (A) for alkaline passivation of metallic components comprising at least in part surfaces of zinc or zinc alloys, containing iron(III) ions, phosphate ions, and one or more complexing agents, where a free alkalinity ranges from 1 to 6 points, and the pH is at least 11. The aqueous compositions (A) can additionally contain nonionic surfactants, so that such compositions are suitable for use in a method in which both cleaning and alkaline passivation of the metallic component occur in one step. The present invention further relates to a method for alkaline passivation of metallic components by contacting them with composition (A), and further a method for surface treatment in automobile body production, in which the alkaline passivation step using composition (A) is followed by an acid passivation step using a composition (B).

Abstract: A method for recovering demineralized water from zirconium-containing rinse water having a pH lower than 6.0, wherein a) the rinse water has added to it an aqueous solution of Ca(OH)2 containing no more than 0.1 wt % undissolved Ca(OH)2, in a quantity such that the pH of the rinse water rises to a value in the range from 6.2 to 8.0, b) a precipitate that forms is separated from the rinse water, and c) the rinse water from which the precipitate was removed in step b) is subjected to an ion exchange method or to reverse osmosis.

Abstract: The present invention relates to a method for serial surface treatment of metallic components comprising aluminum surfaces, wherein an alkaline pretreatment is followed by a conversion treatment. According to the invention, the intention during the alkaline pretreatment is that a maximum value for the concentration of dissolved zinc is not exceeded, in order to ensure a sufficient quality of the corrosion-protective coating on the aluminum surface of the components following the surface treatment. In a preferred embodiment, the content of dissolved zinc is effectively held below the respective bath-typical maximum value of dissolved zinc by the addition of compounds constituting a source of sulfide ions. The functionality of the surface treatment can be additionally increased by likewise controlling the content of dissolved aluminum in the alkaline pretreatment such that, by adding compounds constituting a source for silicate anions, a threshold value for dissolved aluminum is not exceeded.

Abstract: The invention relates to an aqueous composition and to a method for the anticorrosion conversion treatment of metallic surfaces, particularly metallic materials which are assembled into composite structures, comprising steel or galvanized or alloy-galvanized steel and any combinations thereof, the composite structure being composed at least in part of aluminum or the alloys thereof. The aqueous composition according to the invention is based on a phosphating solution and contains, in addition to water-soluble compounds of zirconium and titanium, a quantity of free fluoride in a ratio that both permits phosphating of the steel and galvanized and/or alloy-galvanized steel surfaces and determines low pickling rates of the aluminum substrate with simultaneous passivation of the aluminum.

Abstract: The present invention relates to a chromium-free aqueous agent based on water-soluble compounds of titanium and/or zirconium and a source of fluoride ions, copper ions and metal ions selected from the group consisting of calcium, magnesium, aluminum, boron, zinc, iron, manganese and/or tungstene and to a method for the anti-corrosive conversion treatment of metal surfaces. The chromium-free aqueous agent is suitable for the treatment of various metal materials, joined in composite structures, amongst others of steel or galvanized steel or the alloys thereof or any combinations of said materials. Furthermore, surfaces of aluminum and alloys thereof can be treated in an anti-corrosive manner using the agent according to the invention. The anti-corrosive treatment is intended in particular as a pretreatment for a subsequent dip-coating.

Abstract: The present invention relates to an aqueous composition and to a method for the anticorrosion conversion treatment of metallic surfaces, particularly metallic materials which are assembled into composite structures, comprising steel or galvanized or alloy-galvanized steel and any combinations of these materials, the composite structure being composed at least in part of aluminum or the alloys thereof. The aqueous composition according to the invention is based on a phosphating solution and contains, in addition to water-soluble compounds of zirconium and titanium, a quantity of free fluoride in a ratio that both permits phosphating of the steel and galvanized and/or alloy-galvanized steel surfaces and determines low pickling rates with regard to the aluminum substrate with simultaneous passivation of the aluminum.

Abstract: The invention relates to an acidic, aqueous, chromium-free composition (A) for the anti-corrosive treatment of steel and/or galvanized steel surfaces comprising metal ions (M) selected from ions at least of the elements nickel, cobalt, molybdenum, iron or tin and a multi-stage method applying the composition (A) for the anti-corrosive pre-treatment of metal components which have steel and/or galvanized steel surfaces. The invention further relates to metal surfaces of zinc or iron having a passive layer system comprising at least 30 mg/m2 nickel and at least 10 mg/m2 zircon, titanium and/or hafnium and sulfur, wherein nickel is present in metallic form at up to at least 30 At. %, obtainable in a method according to the invention.

Abstract: The present invention relates to a method for improving the corrosion-protecting pre-treatment of metal surfaces and using rinse water in a manner to conserve resources in such a corrosion-protecting pre-treatment, comprising a conversion treatment step using an aqueous composition comprising at least 50 ppm of the elements B, Si, Ti, Zr and/or Hf in the form of water-soluble compounds at a pH value of 3 to 5.5, wherein a minimum fraction of 10 ppm of the elements B, Si, Ti, Zr and/or Hf in the form of water-soluble compounds is present in the last pre-rinse step and a portion of the aqueous composition of the conversion treatment step is contained in the first post-rinse step. The resource-conserving use of the rinse water is accomplished according to the invention by way of a cascaded return of rinse water from the last rinse step to the first rinse step.

Abstract: The present invention relates to the field of phosphating for corrosion-protective pretreatment of zinc surfaces, being directed toward the use of largely nickel- and cobalt-free zinc phosphating solutions. The present invention makes available an alternative to trication zinc phosphating, in which the zinc surfaces of a component are firstly, before zinc phosphating, passivated with an alkaline composition containing iron(III) ions, and thereby preconditioned for a largely nickel- and cobalt-free zinc phosphating operation. In a further aspect, the invention relates to a component, in particular an automobile body, that comprises at least in part surfaces made of zinc, the zinc surfaces being covered by a two-layer system made up of a first, inner passive layer containing iron and resting on the zinc surface, and a second, outer crystalline zinc phosphate layer resting on the inner layer.

Abstract: The present invention relates to an aqueous alkaline composition (A) for alkaline passivation of metallic components comprising at least in part surfaces of zinc or zinc alloys, containing iron(III) ions, phosphate ions, and one or more complexing agents, where a free alkalinity ranges from 1 to 6 points, and the pH is at least 11. The aqueous compositions (A) can additionally contain nonionic surfactants, so that such compositions are suitable for use in a method in which both cleaning and alkaline passivation of the metallic component occur in one step. The present invention further relates to a method for alkaline passivation of metallic components by contacting them with composition (A), and further a method for surface treatment in automobile body production, in which the alkaline passivation step using composition (A) is followed by an acid passivation step using a composition (B).

Abstract: The invention relates to an acidic, aqueous, chromium-free composition (A) for the anti-corrosive treatment of steel and/or galvanized steel surfaces comprising metal ions (M) selected from ions at least of the elements nickel, cobalt, molybdenum, iron or tin and a multi-stage method applying the composition (A) for the anti-corrosive pre-treatment of metal components which have steel and/or galvanized steel surfaces. The invention further relates to metal surfaces of zinc or iron having a passive layer system comprising at least 30 mg/m2 nickel and at least 10 mg/m2 zircon, titanium and/or hafnium and sulfur, wherein nickel is present in metallic form at up to at least 30 At. %, obtainable in a method according to the invention.

Abstract: A process for the anticorrosive treatment of metal components that have been heat-treated at a temperature of at least 100° C. and at least partially comprise zinc surfaces, wherein the surfaces of the component that consist of zinc already partially have a crystalline zinc phosphate layer, wherein the cleaned component is given an activating pretreatment with an acidic aqueous dispersion of insoluble phosphates having a pH of not less than 4 and the component is subsequently subjected to a phosphating conversion treatment before electrocoating is applied. The invention also comprises the use of metal components that have been treated in such a process, for the application of multilayer systems and in particular for the manufacture of bodies in automobile production.

Abstract: The invention relates to an aqueous composition and to a method for the anticorrosion conversion treatment of metallic surfaces, particularly metallic materials which are assembled into composite structures, comprising steel or galvanized or alloy-galvanized steel and any combinations thereof, the composite structure being composed at least in part of aluminum or the alloys thereof. The aqueous composition according to the invention is based on a phosphating solution and contains, in addition to water-soluble compounds of zirconium and titanium, a quantity of free fluoride in a ratio that both permits phosphating of the steel and galvanized and/or alloy-galvanized steel surfaces and determines low pickling rates of the aluminum substrate with simultaneous passivation of the aluminum.

Abstract: The present invention relates to a method for improving the corrosion-protecting pre-treatment of metal surfaces and using rinse water in a manner to conserve resources in such a corrosion-protecting pre-treatment, comprising a conversion treatment step using an aqueous composition comprising at least 50 ppm of the elements B, Si, Ti, Zr and/or Hf in the form of water-soluble compounds at a pH value of 3 to 5.5, wherein a minimum fraction of 10 ppm of the elements B, Si, Ti, Zr and/or Hf in the form of water-soluble compounds is present in the last pre-rinse step and a portion of the aqueous composition of the conversion treatment step is contained in the first post-rinse step. The resource-conserving use of the rinse water is accomplished according to the invention by way of a cascaded return of rinse water from the last rinse step to the first rinse step.

Abstract: A process for the anticorrosive treatment of metal components that have been heat-treated at a temperature of at least 100° C. and at least partially comprise zinc surfaces, wherein the surfaces of the component that consist of zinc already partially have a crystalline zinc phosphate layer, wherein the cleaned component is given an activating pretreatment with an acidic aqueous dispersion of insoluble phosphates having a pH of not less than 4 and the component is subsequently subjected to a phosphating conversion treatment before electrocoating is applied. The invention also comprises the use of metal components that have been treated in such a process, for the application of multilayer systems and in particular for the manufacture of bodies in automobile production.

Abstract: The present invention relates to a chromium-free aqueous agent based on water-soluble compounds of titanium and/or zirconium and a source of fluoride ions, copper ions and metal ions selected from the group consisting of calcium, magnesium, aluminum, boron, zinc, iron, manganese and/or tungstene and to a method for the anti-corrosive conversion treatment of metal surfaces. The chromium-free aqueous agent is suitable for the treatment of various metal materials, joined in composite structures, amongst others of steel or galvanized steel or the alloys thereof or any combinations of said materials. Furthermore, surfaces of aluminum and alloys thereof can be treated in an anti-corrosive manner using the agent according to the invention. The anti-corrosive treatment is intended in particular as a pretreatment for a subsequent dip-coating.

Abstract: A method for recovering demineralized water from zirconium-containing rinse water having a pH lower than 6.0, wherein a) the rinse water has added to it an aqueous solution of Ca(OH)2 containing no more than 0.1 wt% undissolved Ca(OH)2, in a quantity such that the pH of the rinse water rises to a value in the range from 6.2 to 8.0, b) a precipitate that forms is separated from the rinse water, and c) the rinse water from which the precipitate was removed in step b) is subjected to an ion exchange method or to reverse osmosis.

Abstract: The present invention relates to an aqueous composition and to a method for the anticorrosion conversion treatment of metallic surfaces, particularly metallic materials which are assembled into composite structures, comprising steel or galvanized or alloy-galvanized steel and any combinations of these materials, the composite structure being composed at least in part of aluminum or the alloys thereof. The aqueous composition according to the invention is based on a phosphating solution and contains, in addition to water-soluble compounds of zirconium and titanium, a quantity of free fluoride in a ratio that both permits phosphating of the steel and galvanized and/or alloy-galvanized steel surfaces and determines low pickling rates with regard to the aluminum substrate with simultaneous passivation of the aluminum.