METHOD FOR PLATING A MOVING METAL STRIP AND COATED METAL STRIP PRODUCED THEREBY

摘要

A method for producing a steel substrate coated with a chromium metal-chromium oxide (Cr—CrOx) coating layer in a continuous high speed plating line, operating at a line speed (v1) of at least 100 m·min−1, wherein one or both sides of the electrically conductive substrate in the form of a strip, moving through the line, is coated with a chromium metal-chromium oxide (Cr—CrOx) coating layer from a single electrolyte by using a plating process. A coated steel substrate and a packaging made thereof.

主权项

1. A method for producing a steel substrate coated with a chromium metal-chromium oxide (Cr—CrOx) coating layer in a continuous high speed plating line, operating at a line speed (v1) of at least 100 m·min−1,
wherein one or both sides of the electrically conductive substrate in the form of a strip, moving through the line, is coated with a chromium metal-chromium oxide (Cr—CrOx) coating layer from a single electrolyte by using a plating process, wherein the substrate is a steel substrate which acts as a cathode and wherein the CrOx deposition is driven by the increase of the pH at the substrate/electrolyte interface due to the reduction of H+ to H2(g), and wherein the increase of pH is counteracted by a diffusion flux of H+-ions from the bulk of the electrolyte to the substrate/electrolyte interface and wherein this diffusion flux of H+-ions from the bulk of the electrolyte to the substrate/electrolyte interface is reduced by
increasing the kinematic viscosity of the electrolyte, and/orby moving the strip and the electrolyte through the plating line in concurrent flow wherein the steel strip is transported through the plating line with a velocity (v1) and wherein the electrolyte is transported through the strip plating line with a velocity of v2, thereby reducing the current density to deposit CrOx and reducing the amount of H2(g) formed at the substrate/electrolyte interface.