Method and apparatus for electrolytically depositing a deposition metal on a workpiece
For improving the current transfer during the electrolytic metallization of workpieces, a method is proposed: (a) providing a metal depositing apparatus 17 , in which the workpiece, at least one anode 40, 41 and a metal deposition electrolyte AE are arranged and which has a device for electric current generation 60 and at least one current feeding device 31 with in each case at least one electrical contact element 34, 35 for making electrical contact with the workpiece; (b) bringing the at least one electrical contact element 34, 35 into contact with the workpiece; and (c) feeding electric current to the workpiece via the at least one electrical contact element 34, 35 in order that the deposition metal deposits on the workpiece. Before method step (b), in a further method step (d), deposition metal is deposited on the at least one electrical contact element 34, 35.
1. An apparatus for electrolytically depositing a deposition metal on a workpiece, comprising:
(I) in a first region of the apparatus:
(a) an electrolytic depositing apparatus, which has at least one anode and at least one current feeding device, each current feeding device having one electrical contact element for making electrical contact with the workpiece, each electrical contact element having at least one contact area, wherein the at least one anode and the at least one current feeding device can be brought into contact with a deposition electrolyte; and
(b) a device for electric current generation;
(II) in a second region of the apparatus:
(a) a stripping apparatus for removing deposition metal from the at least one current feeding device, wherein the stripping apparatus comprises a stripping cathode; and
(b) a current source which is designed so as to polarize the stripping cathode cathodically vis-à-vis the at least one current feeding device;
(III) in a third region of the apparatus:
(a) a contact coating apparatus for depositing the deposition metal on the respective contact area on the electrical contact elements, in which contact coating apparatus the at least one electrical contact element is not in contact with the workpiece, wherein the contact coating apparatus comprises a contact coating anode; and
(b) a current source which is designed so as to polarize the electrical contact elements cathodically vis-à-vis the contact coating anode;
wherein the at least one current feeding device is a contact clamp having said contact areas; wherein the contact clamp has two electrical contact elements, each electrical contact element having a said contact area, and
wherein in the second region and in the third region, contact areas of the clamp remain in the position spaced apart from one another.
2. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 1 , wherein the apparatus is a continuous apparatus for continuous electrolytic metal deposition with a plurality of current feeding devices, in which the current feeding devices are held on a holding device forming a circulation, wherein the continuous apparatus has, in the first region of the circulation in the apparatus, a transport path for the workpiece and a guide for the current feeding devices parallel to the transport path, such that the electrical contact elements can be brought into contact with the workpieces and deposition metal can be deposited on the workpieces, and wherein the continuous apparatus is designed, at the end of the first region, to release the contact between the workpieces and the electrical contact elements, wherein the stripping apparatus for removing the deposition metal deposited on the electrical contact elements furthermore forms the second region of the circulation in the apparatus, and wherein the contact coating apparatus for depositing the deposition metal on the electrical contact elements forms the third region of the circulation in the apparatus.
3. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein the transport path is horizontal.
4. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein the holding device is a continuously circulating transport belt or a continuously circulating transport chain.
5. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein the stripping apparatus is at least half as long and at most three times as long as the contact coating apparatus.
6. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein the at least one electrical contact element is made of a base metal which has a surface roughness having a roughness value Ra in a range of from 0.2 to 10 μm.
7. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein the at least one contact clamp is designed so as to exert a clamping pressure per unit of a contact area on the workpiece which is from 0.15 to 2.5 N/mm2.
8. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein the electrical contact elements are arranged parallel to one another and aligned in a manner situated parallel opposite one another.
9. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein the at least one electrical contact element is made of a metal selected from the group consisting of titanium, niobium, and stainless steel.
10. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein stripping cathode is arranged opposite the at least one current feeding device.
11. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein a contact coating anode is arranged between two contact elements of a respective current feeding device.
12. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein the contact coating anode is disposed in the contact coating apparatus with respect to the at least one current feeding device so as to deposit metal on areas of the at least one current feeding device which are adjacent to a respective contact area on the at least one electrical contact element.
13. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 2 , wherein the contact coating anode is made of titanium which is coated with platinum or coated with a mixed oxide.
14. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 1 , wherein the at least one electrical contact element is made of a base metal which has a surface roughness having a roughness value Ra in a range of from 0.2 to 10 μm.
15. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 1 , wherein the at least one contact clamp is designed so as to exert a clamping pressure per unit of a contact area on the workpiece which is from 0.15 to 2.5 N/mm2.
16. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 1 , wherein the electrical contact elements are arranged parallel to one another and aligned in a manner situated parallel opposite one another.
17. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 1 , wherein the at least one electrical contact element is made of a metal selected from the group consisting of titanium, niobium, and stainless steel.
18. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 1 , wherein stripping cathode is arranged opposite the at least one current feeding device.
19. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 1 , wherein a contact coating anode is arranged between two contact elements of a respective current feeding device.
20. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 1 , wherein the contact coating anode is disposed in the contact coating apparatus with respect to the at least one current feeding device so as to deposit metal on areas of the at least one current feeding device which are adjacent to the respective contact area on the at least one electrical contact element.
21. The apparatus for electrolytically depositing a deposition metal on a workpiece according to claim 1 , wherein the contact coating anode is made of titanium which is coated with platinum or coated with a mixed oxide.