Continuous process for the electrogalvanizing of metal strip in a chloride-based plating solution in order to obtain coatings with low rugosity at high current densities

摘要

An electrogalvanizing process, in which a strip is moved past an anode, plating solution is made to flow at a speed V with respect to the moving strip, and an electric current of current density J greater than 50 A/dm. sup.2 is passed between the strip and the anode, which comprises carrying out the deposition under conditions such that:P PJ/J.sub. lim is less than or equal to 0.15;PPJ. sup.2 /J.sub.lim is less than or equal to 22 A/dm.sup.2 ;P Pwhere J.sub.lim is the limiting current density, corresponding to the current density plateau in the current versus potential curve characteristic of the plating solution flowing at the speed V in the vicinity of the strip. An electroplating cell of the radial type for implementing the process, in which cell the anode bed is continuous, is disclosed. The process facilitates the high-speed deposition of zinc which has low rugosity and is free of edge dendrites.