Process for coating a substrate, plant for implementing the process and feeder for feeding such a plant with metal

1. A coating plant for continuously coating a substrate on at least one of its sides with a layer of a sublimable metal or metal alloy, comprising:

a vacuum chamber;

a vacuum evaporation coater located inside the vacuum chamber;

a substrate running through the vacuum evaporation coater in a plane in a first direction;

a feeder located inside the vacuum chamber for feeding the coater with a metal or metal alloy, the feeder including an inclined plane inclined in the first direction; and

a plurality of ingots on the inclined plane subliming into the metal or metal alloy, the plurality of ingots being in contact with one another and moved by the feeder up the inclined plane so that a surface of the ingots facing the side of the substrate to be coated remains parallel to and at a constant distance from the substrate as the vacuum evaporation coater evaporates the ingots while the ingots are fully on the inclined plane.

2. The coating plant according to claim 1 , in which said feeder comprises a piston.

3. The plant according to claim 1 , wherein said ingots are in contact with the inclined plane via their side opposite that facing said substrate, the feeder moving the ingots transversely to the first direction, the inclined plane becoming closer to the plane as the ingots move transversely to the first direction, the inclined plane compensating for evaporation of the ingots so that the surface of the ingots facing the side of the substrate remains parallel to and at a constant distance from the substrate.

4. The plant according to claim 3 , in which said feeder includes at least one piston acting on a first ingot in contact with a first end of said inclined plane, and extending transversely relative to the substrate, said first ingot acting in turn on the ingots on said inclined plane as far as a second end of the inclined plane.

5. The plant according to claim 4 , further comprising a second inclined plane provided with further ingots and with a second piston acting on a first further ingot in contact with the first end of said second inclined plane.

6. The plant according to claim 5 , comprising two tanks for recovering, by gravity, the spent ingots, said tanks being placed beneath each second end of said inclined plane and second inclined plane.

7. The plant according to claim 1 , wherein said ingots are in contact with the inclined plane via their side opposite that facing said substrate, the feeder moving the ingots in the first direction, the inclined plane becoming closer to the plane as the substrate and ingots move in the first direction, the inclined plane compensating for evaporation of the ingots so that the surface of the ingots facing the side of the substrate remains parallel to and at a constant distance from the substrate.

8. The plant according to claim 7 , in which said feeder includes at least one piston acting on a first ingot in contact with a first end of said inclined plane, and extending longitudinally relative to the substrate, said first ingot acting in turn on the ingots on said inclined plane as far as a second end of the inclined plane.

9. The plant according to claim 8 , comprising a tank for recovering, by gravity, the spent ingots, said tank being placed beneath said second end of the inclined plane.

10. The plant according to claim 7 , in which the substrate runs vertically, said feeder comprising at least one vertical plate on which said ingots are stacked, said plate being in contact with at least one vertical piston.

11. The plant according to claim 1 , further comprising a second feeder facing another side of said substrate, it being possible for each of the feeder and the second feeder to contain an identical or different metal or metal alloy, and a second vacuum evaporator facing the other side of said substrate, the second feeder and the second vacuum evaporator being placed within the vacuum chamber.

12. The plant according to claim 1 , in which said vacuum chamber has a reactive atmosphere.

13. The plant according to claim 1 , in which said vacuum evaporation coater is a plasma vacuum evaporation coater.

14. The plant according to claim 13 , further comprising at least one magnet for confining a plasma of the evaporation coater.

15. The plant according to claim 1 , in which said ingots of a metal or metal alloy are chosen from zinc, magnesium, chromium, manganese, silicon and alloys thereof.

16. A feeder for feeding a vacuum coating plant, as defined in claim 1 , with a metal or metal alloy.

17. The plant according to claim 1 , further comprising a support roll supporting the substrate.

18. The plant according to claim 1 , further comprising a counterelectrode beneath the feeder, the substrate defining an electrode, a plasma being created between the counterelectrode and substrate.

19. The plant according to claim 1 , wherein the vacuum evaporation coater sublimes the ingots.

20. The coating plant according to claim 1 , wherein the plurality of ingots have heights decreasing in the first direction.

21. A coating plant for continuously coating a substrate on at least one of its sides with a layer of a sublimable metal or metal alloy, comprising:

a vacuum chamber containing:

a vacuum evaporation coater, said substrate running through the coater in a plane in a first direction; and

a feeder for feeding the coater with a metal or metal alloy, said metal or metal alloy being in the form of ingots, said ingots being in contact with one another and moved by the feeder up an inclined plane, the inclined plane compensating for evaporation of the ingots to aid in keeping a surface of said ingots facing the side of the substrate to be coated parallel to and at a constant distance from said substrate as the coater evaporates the ingots while the ingots are fully on the inclined plane.