GB1230375A - - Google Patents

Abstract

1,230,375. Electrolytic treatment barrels. MUREX Ltd. April 5, 1968 [May 18, 1967], No.23256/67. Heading C7B. In a process of surfacing a workpiece by electrodeposition (e.g. by electro-plating) within a barrel which is rotatable about a substantially horizontal axis and has the anode disposed therein, those surfaces of the barrel which contact the workpiece are of a "valve action" metal such as Ta, Nb, Ti, Zr or Hf and act as a cathode. The anode, which may comprise a rod or cage, may also have a surface of valve action metal. The barrel may be of circular or polygonal cross-section and may be of slotted, perforated or meshed material. Fig.1 shows an electro-plating barrel comprising a framework 1, end plates 2 of electrically insulated material, "valve action" metal mesh 4 and a frame 5 detachably securable to the framework 1 by cam closure devices 6. The barrel is carried by a pair of hollow shafts 8 and is rotatable by a pulley 16. A rod 21 passes axially through the hollow shafts 8 without contacting them and supports anode material in the form of split rings 23. The rod 21 may be independently rotated so as to rotate the rings 23. Electrical connection to the rings 23 is via the rod 21 and a clamp 22. Electrical connection to the metal mesh 4 is via T-shaped strips 19, one of the hollow shafts 8, a slip ring 18 and brush gear 17. Alternatively to the split rings 23, the anode may comprise a cylindrical cage (24) Fig.3, (not shown) containing anodic metal such as shot, bar or rod, the cage being eccentrically mounted on a shaft (25) and the shaft (25) being mounted similarly to the rod 21. The barrel may be immersed in and withdrawn from a bath of electrolyte by means of a pivoted frame (28) Fig.4, (not shown), the bearings 9 and clamps 22 of the barrel apparatus being mounted on brackets 33 of the pivoted frame 28. Parts of the barrel apparatus which become plated during the electro-plating can have the plating removed therefrom by reversing the polarity of the system. The workpieces may comprise metal articles or metal in massive or powder form. The Specification refers to matter claimed in Specification 1,230,376.