Part coated with a carbon-based layer
The invention relates to a metal part comprising a metallic substrate (S) having an outer surface coated with a layer of carbon-based material (M). According to the invention, the layer of carbon-based material: —is of “DLC” amorphous carbon type, from the a-C family; • comprises less than 3 at % of oxygen within the layer of carbon-based material; • does not contain hydrogen, nitrogen, or doping elements.
1 . A metal part comprising a metallic substrate(S), having an outer surface coated with a carbon-based material (M) outer layer, wherein the carbon-based material layer:
is an amorphous diamond-like carbon (“DLC”) and an “a-C” carbon;
comprises oxygen, in an amount of at most 3 at % of oxygen within the carbon-based material layer; and
does not contain hydrogen, nitrogen, or doping elements,
and wherein the substrate is a plate with a thickness between 10 μm and 1000 μm.
2 . The metal part according to claim 1 , comprising a carbon-based sublayer (SC) located between the substrate(S) and the carbon-based material (M), in contact with said carbon-based material (M), the carbon sublayer (SC) comprising between 3 at % and 15 at % of residual oxygen.
3 . A plate of monopolar or bipolar type for a fuel cell, comprising the metal part according to claim 1 .
4 . A method for forming a metal part according to claim 1 by depositing, with ion assistance, a carbon-based material (M) outer layer on a metallic substrate(S), the deposition being done according to one of the techniques from among:
magnetron sputtering, continuously or pulsed,
high power impulse magnetron sputtering (HiPIMS),
unbalanced configuration magnetron sputtering, and optionally in a closed field,
radiofrequency sputtering (RF sputtering),
or any combination which can be done from these techniques;
said method comprising performing the deposition with an ion assistance, a level of which has been adjusted, such that the carbon-based material (M) layer contains oxygen, in an amount of, at most, 3 at % of oxygen within the carbon-based material (M) layer.
5 . The method according to claim 4 , wherein the material (M) deposited on the substrate(S) forms a layer called thin layer, having a thickness greater than or equal to 20 nm.
6 . The method according to claim 4 , comprising a prior step of depositing a metal sublayer (SC) on the substrate(S) intended to be located between the substrate(S) and the carbon-based material (M), in contact with said substrate(S), the material of the metal sublayer (SC) being chosen from among one or more of the following materials: chromium, titanium, zirconium, tantalum, or their alloys, as well as their nitrides and carbides.
7 . The method according to claim 6 , wherein the thickness of the metal sublayer (SC) is between 5 and 100 nm.
8 . The method according to claim 4 , comprising a prior step of depositing a carbon-based sublayer (SC) between the substrate(S) and the carbon-based material (M), in contact with said carbon-based material (M), and during which the level of the assistance is adjusted, such that the carbon-based sublayer (SC) contains between 3 at % and 15 at % of residual oxygen.
9 . The method according to claim 8 , wherein the carbon-based sublayer (SC) has an oxygen content gradient, which decreases from the substrate(S) in the direction of the carbon-based material (M) layer.
10 . The method according to claim 8 , wherein the thickness of the carbon-based sublayer (SC) is between 2 and 40 nm.
11 . The method according to claim 4 , wherein the substrate(S) comprises a stainless steel, titanium, a titanium alloy, or a nickel, chromium and iron-based alloy.
12 . A plate of monopolar or bipolar type for a fuel cell, comprising the metal part according to claim 2 .
13 . The method according to claim 5 , wherein the thin layer has a thickness of between 20 nm and 500 nm.
14 . The method according to claim 5 , wherein the thin layer has a thickness of between 80 nm and 120 nm.
15 . The method according to claim 5 , comprising a prior step of depositing a metal sublayer (SC) on the substrate(S) intended to be located between the substrate(S) and the carbon-based material (M), in contact with said substrate(S), the material of the metal sublayer (SC) being chosen from among one or more of the following materials: chromium, titanium, zirconium, tantalum, or their alloys, as well as their nitrides and carbides.
16 . The method according to claim 15 , wherein the thickness of the metal sublayer (SC) is between 20 nm and 40 nm.
17 . The method according to claim 15 , comprising a prior step of depositing a carbon-based sublayer (SC) between the substrate(S) and the carbon-based material (M), in contact with said carbon-based material (M), and during which the level of the assistance is adjusted, such that the carbon-based sublayer (SC) contains between 3 at % and 15 at % of residual oxygen.
18 . The method according to claim 9 , wherein the thickness of the carbon-based sublayer (SC) is between 10 nm and 30 nm.
19 . The metal part according to claim 1 , wherein the carbon-based material layer is the outermost layer of the metal part.