Apparatus and method for electroplating a substrate in a continuous way
An apparatus and a method deposits a metal coating on an electrically conductive substrate in a continuous way. The apparatus includes at least one plating vessel for receiving an electrolyte solution and at least one plating unit. The plating unit includes a first zone comprising at least one first electrode (anode) connected to a positive pole of a power supply; a second zone comprising at least one second electrode (cathode) connected to a negative pole of the power supply; and an intermediate zone between the first zone and the second zone. The intermediate zone separates the first zone from the second zone by a predetermined distance larger than zero. The substrate functions as a cathode having a current density Jc when the substrate is facing the first electrode, and as an anode having a current density Ja when the substrate is facing the second electrode.
1. A method to continuously deposit a metal or metal alloy coating on an electrically conductive substrate, said method comprising the steps of:
providing an apparatus comprising at least one plating vessel for receiving an electrolyte solution and at least one plating unit, said at least one plating unit comprising a first zone comprising at least one first electrode connected to a positive pole of a power supply, a second zone comprising at least one second electrode connected to a negative pole of the power supply and at least one intermediate zone between said first zone and said second zone, said intermediate zone separating said first zone from said second zone by a predetermined distance that is larger than zero; and
passing said electrically conductive substrate through said at least one plating vessel in a predetermined direction to deposit said metal or metal alloy coating on said electrically conductive substrate,
wherein said substrate passes consecutively said first zone, said intermediate zone and said second zone, and
wherein said substrate when facing said first electrode is functioning as a cathode having a current density Jc and said substrate when facing said second electrode is functioning as an anode having a current density Ja, said current density Ja being larger than said current density Jc.
2. A method according to claim 1 , wherein a ratio Ja/Jc is at least 10.
3. A method according to claim 1 , wherein said first electrode has a length of at least 30 cm and said second electrode has a length of maximum 5 cm.
4. A method according to claim 1 , wherein said intermediate zone creates a distance between said first zone and said second zone ranging between 1 and 10 cm.
5. A method according to claim 1 , wherein said first electrode, said second electrode, or a combination thereof is shielded.
6. A method according to claim 1 , wherein the at least one plating unit comprises at least two consecutive plating units, and wherein the apparatus further comprises an activation zone between the two consecutive plating units such that said activation zone separates the two consecutive plating units by a separating distance that is larger than zero.
7. A method according to claim 6 , wherein the separating distance between the two consecutive plating units ranges between 1 and 10 cm.
8. A method according to claim 1 , wherein a separating distance between said substrate and said first and second electrodes is lower than 3 cm.
9. A method according to claim 1 , wherein said substrate comprises a metal wire, a metal cord, a metal film, a metallized wire, a metallized cord or a metallized film.
10. A method according to claim 1 , wherein the substrate passes horizontally through said plating vessel.
11. A method according to claim 1 , wherein the substrate passes vertically through said plating vessel.
12. A method according to claim 1 , wherein the metal coating is applied on both sides of said substrate.
13. A method according to claim 1 , wherein external power is not in electrical contact with the substrate via solid electrical connectors.