Disclosed are pretreatment compositions and associated methods for treating metal substrates with pretreatment compositions, including ferrous substrates, such as cold rolled steel and electrogalvanized steel. The pretreatment composition includes: a Group IIIB and/or IVB metal; free fluoride; and lithium. The methods include contacting the metal substrates with the pretreatment composition.

Provided is a solution composition for steel sheet surface treatment, comprising 30 wt % to 60 wt % of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B); 0.2 wt % to 0.4 wt % of a rust-inhibiting and corrosion-resisting agent; 0.1 wt % to 0.3 wt % of a molybdenum-based compound; 5 wt % to 10 wt % of a water-soluble cationic urethane resin; 0.5 wt % to 2.0 wt % of a silane coupling agent; and 27.3 wt % to 64.2 wt % of water, a zinc-based plated steel sheet surface-treated with the same, and a manufacturing method therefor, the zinc-based plated steel sheet surface-treated with the solution composition for steel sheet surface treatment containing trivalent chromium may have an excellent effect on corrosion resistance, blackening resistance, fingerprint resistance, oil resistance, and alkali resistance.

Provided is a solution composition for steel sheet surface treatment, comprising 30 wt % to 60 wt % of a trivalent chromium compound containing chromium phosphate (A) and chromium nitrate (B); 0.2 wt % to 0.4 wt % of a rust-inhibiting and corrosion-resisting agent; 0.1 wt % to 0.3 wt % of a molybdenum-based compound; 5 wt % to 10 wt % of a water-soluble cationic urethane resin; 0.5 wt % to 2.0 wt % of a silane coupling agent; and 27.3 wt % to 64.2 wt % of water, a zinc-based plated steel sheet surface-treated with the same, and a manufacturing method therefor, the zinc-based plated steel sheet surface-treated with the solution composition for steel sheet surface treatment containing trivalent chromium may have an excellent effect on corrosion resistance, blackening resistance, fingerprint resistance, oil resistance, and alkali resistance.

The present invention relates to a method for adjusting a passivation composition by determining the redox potential of a passivation composition as well as to a method for passivating metallic substrates by treatment with a passivation composition.

Described herein is an improved process for anticorrosion pretreatment of a metallic surface including steel, galvanized steel, aluminum, an aluminum alloy, magnesium and/or a zinc-magnesium alloy, wherein the metallic surface is brought into contact with i) an acidic aqueous composition A which includes a1) at least one compound selected from the group consisting of titanium, zirconium and hafnium compounds, and with ii) an aqueous composition B which includes b1) at least one (meth)acrylate resin and b2) at least one phenol resin, where the metallic surface is brought into contact firstly with the composition A and then with the composition B and/or firstly with the composition B and then with the composition A and/or simultaneously with the composition A and the composition B.

Described herein is an improved process for anticorrosion pretreatment of a metallic surface including steel, galvanized steel, aluminum, an aluminum alloy, magnesium and/or a zinc-magnesium alloy, wherein the metallic surface is brought into contact with i) an acidic aqueous composition A which includes a1) at least one compound selected from the group consisting of titanium, zirconium and hafnium compounds, and with ii) an aqueous composition B which includes b1) at least one (meth)acrylate resin and b2) at least one phenol resin, where the metallic surface is brought into contact firstly with the composition A and then with the composition B and/or firstly with the composition B and then with the composition A and/or simultaneously with the composition A and the composition B.

Disclosed is a process alternative to the zinc phosphating and phosphodegreasing processes, which comprises: >Zinc phosphating replacement a. a step of alkaline degreasing of the article to be phosphated; b. a first wash with tap water; c. a second wash with demineralized water; d. a conversion treatment in a bath containing zirconium salts, phosphates, fluoride complexes, ammonia, at least one corrosion inhibitor, at least one process accelerator, at least one sequestering agent, a reaction sludge thickening system, and optionally, titanium and vanadium compounds; e. a final wash before treatment of the article in the oven. >Phosphodegreasing process replacement a. a conversion treatment in a bath containing zirconium salts, phosphates, fluoride complexes, ammonia, at least one corrosion inhibitor, at least one process accelerator, at least one sequestering agent, at least one surfactant, a reaction sludge thickening system, and optionally, titanium and vanadium compounds; b. a wash with tap water; c. a wash with demineralized water before treatment of the article in the oven.

Disclosed is a process alternative to the zinc phosphating and phosphodegreasing processes, which comprises: >Zinc phosphating replacement a. a step of alkaline degreasing of the article to be phosphated; b. a first wash with tap water; c. a second wash with demineralized water; d. a conversion treatment in a bath containing zirconium salts, phosphates, fluoride complexes, ammonia, at least one corrosion inhibitor, at least one process accelerator, at least one sequestering agent, a reaction sludge thickening system, and optionally, titanium and vanadium compounds; e. a final wash before treatment of the article in the oven. >Phosphodegreasing process replacement a. a conversion treatment in a bath containing zirconium salts, phosphates, fluoride complexes, ammonia, at least one corrosion inhibitor, at least one process accelerator, at least one sequestering agent, at least one surfactant, a reaction sludge thickening system, and optionally, titanium and vanadium compounds; b. a wash with tap water; c. a wash with demineralized water before treatment of the article in the oven.

Provided herein is a process for the pretreatment of workpieces having a surface of aluminum or aluminum alloys for noncutting forming and/or joining by welding or adhesive bonding to similarly pretreated, precoated workpieces, or to optionally precoated parts. The parts are composed of steel, galvanized steel, and/or alloy-galvanized steel. Further provided herein is a subsequent permanent corrosion-protecting treatment by phosphating, by means of a chromium-free conversion treatment, by application of primer, or by surface coating, where the workpieces are a) pickled by means of an aqueous, acidic solution comprising mineral acid by dipping or spraying, b) rinsed with water, and c) brought into contact with an aqueous, acidic, chromium-free solution including Zr as complex fluoride and Mo as molybdate by application by dipping or spraying. After subsequent drying, a layer weight from 2 to 15 mg/m.sup.2 of Zr and Mo is formed.

Provided herein is a process for the pretreatment of workpieces having a surface of aluminum or aluminum alloys for noncutting forming and/or joining by welding or adhesive bonding to similarly pretreated, precoated workpieces, or to optionally precoated parts. The parts are composed of steel, galvanized steel, and/or alloy-galvanized steel. Further provided herein is a subsequent permanent corrosion-protecting treatment by phosphating, by means of a chromium-free conversion treatment, by application of primer, or by surface coating, where the workpieces are a) pickled by means of an aqueous, acidic solution comprising mineral acid by dipping or spraying, b) rinsed with water, and c) brought into contact with an aqueous, acidic, chromium-free solution including Zr as complex fluoride and Mo as molybdate by application by dipping or spraying. After subsequent drying, a layer weight from 2 to 15 mg/m.sup.2 of Zr and Mo is formed.