COATED EXTRUSION TOOL
Provided are extrusion tools such as extrusion dies or portions thereof having a surface with at least one coating thereon, and methods of forming the same are disclosed. The at least one coating is formed from a composition that is a metal aluminum nitride or carbonitride with particular characteristics such that the amount of aluminum varies within the coating between a coating outer surface and an intermediate thickness within the coating. The resulting coatings have tailored physical and performance characteristics that result in improved wear and extrusion performance.
1 . An extrusion tool comprising:
a surface that defines a guide channel, the guide channel having a length;
a chemical vapor deposition (CVD) coating disposed on the surface, the coating comprising at least one layer comprising Me 1-x Al x N and/or Me 1-x Al x CN wherein Me is a metal, x is an atomic ratio aluminum relative to the total amount of Me and aluminum; and
the coating having a thickness whereby the value of x varies through the thickness, and whereby the value of x at the outer surface of the coating is different from the value of x at an intermediate thickness.
2 . The tool of claim 1 whereby the value of x at the outer surface of the coating is higher than the value of x at the intermediate thickness of the coating.
3 . The tool of claim 1 or 2 whereby x at the intermediate thickness is from 0.78 to 0.88.
4 . The tool of any one of claims 1 to 3 , whereby x at the outer surface of the coating thickness is from 0.85 to 0.92.
5 . The tool of any one of claims 1 to 4 , wherein the coating comprises a metal aluminum carbonitride composition having a formula Me 1-x Al x C y N 1-y wherein y is from 0.01 to 0.08.
6 . The tool of any one of claims 1 to 5 , wherein Me is at least one selected from titanium, chromium, zirconium, hafnium, and vanadium.
7 . The tool of any one of claims 1 to 6 , wherein the coating has uniform thickness or substantially uniform thickness over the entirety of the tool surface.
8 . The tool of any one of claims 1 to 7 , wherein a microhardness of the outer region is lower than a microhardness of an intermediate region of the coating.
9 . The tool of any one of claims 1 to 8 , wherein the outer surface of the coating has a microhardness of 2300 HV 0.025 to 2900 HV 0.025 .
10 . The tool of any one of claims 1 to 9 , wherein an intermediate region of the coating has a microhardness of 3000 HV 0.025 to 3600 HV 0.025 .
11 . The tool of any one of claims 1 to 10 , wherein a crystal structure of the coating composition varies through the thickness; and
the outer surface of the coating comprising a mixed phase structure of both cubic and hexagonal wurtzite crystal forms.
12 . The tool of any one of claims 1 to 11 , wherein a crystal structure of the coating composition varies through the thickness; and
the intermediate thickness of the coating comprises a cubic crystal form.
13 . The tool of any one of claims 1 to 12 , wherein the thickness comprises three layers with a first layer comprising TiN, a second layer at the intermediate thickness comprising a cubic phase structure, and the outer surface of the coating layer comprising a mixed phase structure of both cubic and a hexagonal wurtzite crystal forms.
14 . The tool of any one of claims 1 to 13 , further including a second CVD coating disposed atop said CVD coating, the second CVD coating being selected from the group consisting of: a coating comprising hexagonal wurtzite metal aluminum nitride and/or carbonitride; a coating comprising BN; a coating comprising MoS 2 ; a coating comprising WS 2 ; a self-lubricating coating; and any combination thereof.
15 . The tool of any one of claims 1 to 14 , wherein the coating is disposed on the surface of a tool body, the tool body being formed of a steel composition or a ceramic composition.
16 . The tool of any one of claims to 1 to 15 , wherein the tool is selected from a forming die, an extrusion die, and a die component.
17 . A method of forming a extrusion tool, the method comprising:
providing an extrusion tool comprising guide channel defined by a surface; and
depositing a plurality of precursor materials on the surface by chemical vapor deposition (CVD) thereby causing a coating to form on the surface, the coating comprising at least one layer comprising Me 1-x Al x N and/or Me 1-x Al x CN wherein Me is a metal, x is an atomic ratio aluminum relative to the total amount of Me and aluminum; and
the coating having a thickness whereby the value of x varies through the thickness, and whereby the value of x at the outer surface of the coating is different from the value of x at an intermediate thickness.
18 . The method of claim 17 , wherein depositing the plurality of precursor materials comprises depositing a plurality of materials selected from hydrogen, nitrogen, carbon, an aluminum halide compound, a metal halide compound, ammonia, and a hydrocarbon.
19 . The method of claim 17 or 18 , wherein depositing the plurality of precursor materials comprises depositing each one of the plurality of precursor materials simultaneously.
20 . The method of any one of claims 17 to 19 , wherein depositing the plurality of precursor materials comprises depositing the plurality of precursor materials in an environment having a temperature of 650 degrees Celsius to 1050 degrees Celsius.
21 . The method of any one of claims 17 to 20 , wherein depositing the plurality of precursor materials comprises depositing the plurality of precursor materials in an environment having a pressure of 1 mbar to 60 mbar.
22 . The method of any one of claims 17 to 21 , wherein depositing the plurality of precursor materials comprises depositing the plurality of precursor materials for at least 20 minutes, preferably for 30 minutes to 360 minutes.
23 . The method of any one of claims 17 to 22 , wherein depositing the plurality of precursor materials comprises depositing at least one of the plurality of precursor materials at a flow rate of 0.1 L/min to 250 L/min.
24 . The method of any one of claims 17 to 23 , wherein depositing the plurality of precursor materials comprises depositing at least one of the plurality of precursor materials at a flow rate of 50 g/h to 100 g/h.
25 . The method of any one of claims 17 to 24 , wherein a microhardness of the outer region is lower than a microhardness of an intermediate region of the coating.
26 . The method of any one of claims 17 to 25 , wherein the value of x at the outer surface of the coating is higher than the value of x at the intermediate thickness of the coating.
27 . The method of any one of claims 17 to 26 , wherein Me is at least one selected from titanium, chromium, zirconium, hafnium, and vanadium.
28 . The method of any one of claims 17 to 27 , wherein:
hydrogen is supplied at a flow rate of 10-250 L/min;
nitrogen is supplied at a flow rate of 0-30 L/min;
ammonia is supplied at a flow rate of 0.2-5 L/min; and
the aluminum halide compound is supplied at a flow rate of 0.1-7 L/min.
29 . The method of any one of claims 17 to 28 , wherein a metal halide compound is provided at a flow rate of 50 g/h to 100 g/h, the metal halide compound being preferably a titanium halide compound, more preferably TiCl 4 .
30 . The method of any one of claims 17 to 29 , wherein a metal halide compound is provided at a flow rate of 0.1-7 L/min, the metal halide compound being preferably a chromium halide compound, more preferably CrCl 3 .
31 . The method of any one of claims 17 to 30 , wherein the coating is deposited at a deposition rate (DR) of 10 μm/h≥DR≥2 μm/h.
32 . The method of any one of claims 17 to 31 , whereby an extrusion tool as defined in any one of claims 1 to 16 is obtained.
33 . An extrusion tool obtainable by the method of any one of claims 17 to 33 .
34 . Use of an extrusion tool as defined in any one of claims 1 to 16 and 33 for extruding metals, in particular aluminum and aluminum alloys.