METHOD FOR ELECTROGALVANIZING METALLIC STRIP IN ELECTROLYTIC BATH OF CHLORIDE BASE FOR OBTAINING FILM HAVING SMALL ROUGHNESS AT HIGH ELECTRIC DENSITY

摘要

PROBLEM TO BE SOLVED: To control the plating surface phase in high-current plating and further to prevent the precipitation of dendrite crystals at the edges of a strip by controlling the relative velocity of the strip and the electrolytic solution and current density at the time of continuously galvanizing the metallic strip in an electrolytic bath of a chloride base circulated by using a radial type electrolytic cell. ;SOLUTION: The current density J is specified to ≥50A/dm², J/Jlim to ≤0.15 and J²/Jlim to ≤22A/dm² at the time of subjecting the traveling material strip to plating while the electrolytic bath of the chloride base is passed at the relative velocity V in the spacing between the strip and cathode. The Jlim referred to here in the threshold current density corresponding to the horizontal part of the current density of the 'current-potential' characteristic curve of the electrolytic bath flowing at the velocity V near the metallic strip. The Jlim is determined by Jlim-AxV. The coefft. A in the equation dependent upon the compsn., temp. and viscosity of the electrolytic bath is empirically determined by Levi-Civita line method.;COPYRIGHT: (C)1997,JPO