Patent GB-412582-A (GB)
Title: Method for the electrodeposition of metal
IPC: C25D7/06
Filed: 1932-12-24
Abstract: 412,582. Electrodeposition of metal. TENNANT, W. J., 111, Hatton Garden, London.-(Copperweld Steel Co. ; Glassport, Pennsylvania, U.S.A.) Dec. 24, 1932, No. 23016/33. Divided on 412,577. [Class 41.] In a process for the electrodeposition of metal on a wire or core, the core is rotated axially while passing through the cell or cells, and an increasing current density per unit area of cathode surface is applied as the cross-section increases. In the apparatus shown the core 6 passes first through electrolytic cleaning cells 3, 4, 5 containing solutions of soda, sulphuric acid and nitric acid respectively. The cells 3, 4 are connected as electrodes the core forming an intermediate electrode ; the cell 5 is provided with an iron plate 149 as anode. The core then passes through a nickel-depositing cell 7 containing nickel sulphate solution, an initial copper-depositing cell 8 in which the electrolyte is maintained at 70 F., and further copper depositing cells 9 containing acid copper sulphate solution at 140 C. Stationary anodes 151 are spaced along the nickel-depositing cell 7 ; these are of varying resistance or are connected to the generator through varying resistances 156 so as to maintain a uniform current density. Stationary anodes are also employed in the initial copper-depositing cell 8 and in the final cell. At the entrance to the cell 8, the core passes through a short circular anode 130 of lead or other insoluble metal to produce a high initial current density in order to prevent displacement of the nickel. In the intermediate cells the anode consists of a copper wire 31 drawn through them parallel to the core. Connection to the anode wire 31 is made within each cell by a brush 134<1>, Fig. 15, mounted in a guide 134, the wire being supported at the contact point by a porcelain base 132 resting on the lead lining of the cell. Shields 185 are provided to prevent excessive current density at the ends. The increasing conductivity of the core as deposition proceeds may be more than sufficient to produce the desired increase of current density. To compensate for this the length of the cells or the interval between contacts may be increased towards the delivery end. Electrical connection with the core is made by copper rollers bearing on it between the baths ; acidulated water is supplied to the axles of the rollers from which it escapes by perforations and trickles on to the core. The core may be supported between the baths by additional rollers the axes of which are disposed at an acute angle to the core. The contact rollers may alternatively be power-driven and mounted within the baths ; they may be provided with scrapers for removal of metal deposited thereon. The contact shown in Fig. 21 comprises a pair of rollers 190 each consisting of two truncated cones which are slightly displaced relatively to one another ; the hollow and perforated axles 192 are connected to a copper pipe 194 supplying acidulated water, the pipe also serving as the electric connection. The rollers shown compact the deposited metal along helical paths and produce a refined grain structure. The invention is particularly described in its application to a complete process and apparatus comprising the passage of the core through the cells while rotating and under considerable tension as claimed in Specification 412,577 and the recirculation of the electrolyte as claimed in Specification 412,563. Specification 368,412 also is referred to.