Sollac

Sollac (societe Anonyme)

Isabelle Marolleau

Jacques Petitjean

Alain Bello

Jean-Denis Girardier

Nicolas Kopytowski

Joel Marsal

Genevieve Klam

Marie Lombardi

A bath of pH higher than 4 containing more than 1 mole/liter of Zn.sup.++ ions and at least one polyethylene glycol polymer of the general formula R.sup.1 --O(CH.sub.2 --CH.sub.2 --O).sub.n --R.sup.2, in which n.ltoreq.13 and in which the concentration of polymer in the bath is adapted to incorporate in the coat an organic compound having a content by weight greater than 0.1%, expressed as weight of carbon per unit weight of the coat. The bath is adapted to high current densities, and the coat applied on the steel sheet imparts both a leveling effect and an improvement of corrosion resistance.

Aqueous electrodeposition bath based on chlorides for preparation of a

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: J/J.sub.lim is less than or equal to 0.15; J.sup.2 /J.sub.lim is less than or equal to 22 A/dm.sup.2 ; where 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.

Continuous process for the electrogalvanizing of metal strip in a

According to this process, the strip runs through a bath of at least one electrolytic cell and two metal layers are successively deposited onto its surface by adjusting the current feeding the electrolytic cell so that the average value of the current density at the surface of the strip is less than a value called the limiting diffusion current of the ions of the metal to be deposited. In addition, during the formation of the first metal layer, the current is adjusted so as to prevent the appearance of localized overcurrents at the surface of the strip, it being possible for these overcurrents to exceed the limiting diffusion current. Such a process find particular application for electrogalvanizing. Application to an electrogalvanising process.

Process for electroplating a metal strip

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Basse Ham, France

Isabelle Marolleau