Method for Producing a Steel Product with a Zn Coating and a Tribologically Active Layer Deposited on the Coating, and a Steel Product Produced According to Said Method

• Main Authors: Lostak, Thomas, Timma, Christian
• Format: Patent
• Language: English
• Published: 24.01.2019
• Subjects: CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

A method is disclosed which allows a tribologically optimally effective coating to be produced on a steel product surface provided with a Zn-based protective coating using simple products which are nonhazardous with respect to environmental pollution. For this purpose, a correspondingly coated flat steel product is provided, and an aqueous solution consisting of an ammonium sulfate and completely desalinated water is deposited onto the protective coating of the steel product. The concentration of the ammonium sulfate in the aqueous solution is 0.01-5.7 mol/l and the pH value of the aqueous solution is 4-6 with respect to the SO42− ions. At same time, the reaction time near the surface between the aqueous solution and the protective coating is more than 0 seconds and maximally 5 seconds such that a tribologically active layer which consist of ammonium zinc sulfate is provided on the protective coating after a drying process which is carried out without an upstream flushing process. The invention relates to a method which allows a tribologically optimally effective coating to be produced on a steel product surface provided with a Zn-based protective coating using simple products which are nonhazardous with respect to environmental pollution. For this purpose, a correspondingly coated flat steel product is provided, and an aqueous solution consisting of an ammonium sulfate and completely desalinated water is deposited onto the protective coating of the steel product. The concentration of the ammonium sulfate in the aqueous solution is 0.01-5.7 mol/l and the pH value of the aqueous solution is 4-6 with respect to the SO42− ions. At same time, the reaction time near the surface between the aqueous solution and the protective coating is more than 0 seconds and maximally 5 seconds such that a tribologically active layer which consist of ammonium zinc sulfate is provided on the protective coating after a drying process which is carried out without an upstream flushing process.