Vanadium Aluminum Nitride (VAIN) Micro-Alloyed with Ti and / or Si

Abstract

The present invention discloses a high temperature stable ceramic coating structure comprising a microalloy containing the elements Al, V and N, which can be produced by a vapor deposition process.

Description

[Technical Field]

[0001] The present invention relates to a wear-resistant coated alloy comprising at least a transition metal-Al-N alloy coated by a PVD process and / or related processes for high temperature applications above 800°C. [Background technology]

[0002] Conventional technology PVD coatings consisting of metastable c-TM-Al-N are well known for wear-resistant applications (note: "c" is cubic). Akira "TM" means transition metal, "Al" means aluminum, and "N" means nitrogen).

[0003] These coatings exhibit an optimal combination of hardness, fracture resistance, and oxidation resistance, such that a coating as thin as a few microns can significantly extend the life of tools and parts in cutting, forming, and other related applications in the automotive and aerospace industries.

[0004] However, these known coatings consisting of metastable phases exhibit limited thermal stability, measured by hardness as a function of annealing temperature (as shown later in Figure 1), which represents the highest possible application temperature for these coatings.

[0005] Several studies on this subject have revealed that metastable c-TM-Al-N alloys can exhibit hardness enhancement at intermediate annealing temperatures between 800°C and 900°C.

[0006] The main challenge is seen at annealing temperatures above 900°C where the metastable alloys decompose to their ground state, resulting in a loss of hardness, by the following reaction, also shown in Figure 1:

[0007] This decomposition can be shown as follows: Metastable c-TM-Al-N---->c-TMN+w-AlN (1) Here, TM may be, for example, Ti, Cr, Nb, or V.

[0008] The resulting w-AlN has a low elastic modulus of 300 GPa and a low hardness of 25 GPa.

[0009] The aforementioned reduction in hardness caused by phase transformation limits the application temperature of these coatings to prolonged periods of up to 100 hours. exposure In the case of time, the maximum temperature is limited to 800°C, and the maximum is 1 hour. exposure In the case of time, the maximum temperature is limited to 900°C.

[0010] For applications involving high annealing temperatures above 900°C and long exposure times above 100 hours, such as may be the case for hot metal work or turbine tip sealant applications, a superior alloy is required where stable hardness is maintained at temperatures above the annealing temperature of 900°C. Summary of the Invention [Problem to be solved by the invention]

[0011] Object of the invention It is an object of the present invention to mitigate or overcome one or more problems associated with the prior art. In particular, it is an object of the present invention to provide a hard, fracture-resistant, and oxidation-resistant coating structure that is stable at high temperatures and that can be manufactured in a simple and cost-effective manner. [Means for solving the problem]

[0012] Description of the invention We investigated different alloy combinations and surprisingly found that AlVN alloys micro-alloyed with Ti and Si exhibit hardness anomalies that make them more attractive for high temperature applications.

[0013] Thus, in a first aspect of the present invention, a high temperature stable ceramic coating structure comprising a microalloy containing the elements Al, V and N, producible by a vapor deposition process, is disclosed.

[0014] The term high-temperature stable coating structure in the context of the present invention is understood in particular to mean a structure that is stable for long periods up to temperatures of at least 800°C, i.e. a structure that can be used at temperatures above 800°C for up to 100 hours without significant loss of hardness.

[0015] In another example of the first aspect, the coating structure is a metastable coating structure In the form of Formed metastable coating The structure is Multiphase morphology, especially cubic and wurtzite phases, at temperatures above 900°C is.

[0016] In another example of the first aspect, the coating structure exhibits increased hardness and / or increased wear resistance above 900°C, and the increased hardness and / or wear resistance is preferably associated with, and in particular based on, a phase transformation of the coating structure.

[0017] In another example of the first aspect, the coating structure is stable at temperatures above 900° C. for longer exposure times of more than 50 hours, preferably more than 75 hours, especially more than 100 hours. Stable in this context specifically means material stability rather than phase stability.

[0018] In another example of the first embodiment, the coating structure has a layer thickness of less than 10 μm, preferably less than 1 μm, in particular less than 500 nm.

[0019] In another example of the first embodiment, the coating structure is in thin film form or bulk form. In another example of the first aspect, the coating structure is formed as a multi-layer structure.

[0020] In another example of the first embodiment, the microalloy contains only Al and V in addition to N, preferably with a ratio of Al to V of Al 65 V 35 Includes.

[0021] In another example of the first embodiment, the microalloy comprises further elements, preferably Ti and / or Si, in each case in particular in amounts of less than 5 at.-%, in addition to Al, V and N. In addition to these possible further elements, the coating structure according to the invention may also comprise other elements, preferably transition metals, in particular Zr and / or Nb and / or Ta.

[0022] In another example of the first aspect, the microalloy comprises Al, V and N, Ti and Si, and the microalloy preferably comprises Al. 64 V 33 Formed as Ti2Si1N.

[0023] In another example of the first aspect, the coating structure further comprises an oxide and / or a carbide in addition to the nitride. According to the first aspect of the present invention, the coating structure may also comprise a silicide and / or a boride.

[0024] In a second aspect, a vapor deposition process for producing the aforementioned high temperature stable ceramic coated structure is disclosed, the vapor deposition process comprising: depositing a target material comprising the elements Al and V; and depositing the evaporated target material onto a suitable substrate to form a high temperature stable ceramic coated structure.

[0025] According to a second aspect of the invention, the substrate may be formed at least in part as a metal compound.

[0026] In another example of the second embodiment, different target materials are used, and the different target materials are preferably deposited simultaneously.

[0027] In another example of the second embodiment, one of the target materials contains Al and V, preferably Al. 65 V 35 Includes a ratio of

[0028] In another example of the second embodiment, one of the target materials is a mixture of Ti and Si, preferably Ti 75 Si 25 Includes a ratio of

[0029] In another example of the second embodiment, a Co-containing substrate is used, particularly formed as WC-Co.

[0030] In another example of the second embodiment, the substrate temperature is 200°C to 500°C, preferably 300°C to 450°C, and particularly 400°C.

[0031] In another example of the second aspect, a reactive sheathing gas is used, preferably nitrogen as the reactive sheathing gas. In addition to nitrogen, other gases such as argon or methane can be used as the reactive sheathing gas according to the second aspect of the invention.

[0032] In another example of the second embodiment, a negative bias voltage is applied to the substrate during the coating process, the bias voltage being less than 120V, preferably less than 90V, more preferably less than 75V.

[0033] In another example of the second aspect, the coating process is formed as a PVD coating process, preferably as a sputtering process, in particular as a HiPIMS or ARC PVD process.

[0034] In another example of the second embodiment, multiple layers of the aforementioned coating structure are deposited on top of each other to form a multi-layer structure.

[0035] In a third aspect, the use of the aforementioned coating structure for manufacturing cutting and forming tools, in particular for use in the automotive and / or aerospace industries, is disclosed.

[0036] The invention is explained in more detail below by way of example and with reference to the drawings. Detailed Description [Brief explanation of the drawings]

[0037] [Figure 1] FIG. 1 shows the variation in hardness as a function of annealing temperature for TiN and different TM-Al—N. [Figure 2] (a) is a diagram showing a combinatorial deposition chamber used to synthesize a coating of the present invention; (b) is a diagram showing the composition of a coating of the present invention; and (c) is a diagram showing the metal sublattice composition of a coating of the present invention. [Figure 3] FIG. 1(a) shows the hardness variation as a function of annealing temperature for c-AlVTiSiN of the present invention, and (b) shows the X-ray diffractogram of c-AlVTiSiN as a function of annealing temperature. DETAILED DESCRIPTION OF THE INVENTION

[0038] Figure 1 shows the hardness variation as a function of annealing temperature for TiN and different TM-Al-N. As shown in Figure 1, most of the TM-Al-N, such as Ti-Al-N, Cr-Al-N, and Nb-Al-N, show a decrease in hardness at annealing temperatures above 900°C. In contrast, the microalloy AlVN of the present invention shows an increase in hardness as a function of annealing temperatures above 900°C, as shown later in Figure 3. These hardness behaviors were reproducible.

[0039] The proposed alloy may have increased wear resistance due to the high H / E ratio, especially at annealing temperatures above 900°C, making the composition of the present invention interesting for high temperature structural applications.

[0040] Figure 2(a) shows the combination deposition chamber used to synthesize the coating of the present invention, Figure 2(b) shows the composition of the coating of the present invention, and Figure 2(c) shows the metal sublattice composition of the coating of the present invention. According to a first embodiment, the alloy of the present invention is deposited on a WC-Co substrate using an Al 65 V 35 and Ti 75 Si 25 The deposition details are described below.

[0041] The coating from location 2 in Figure 2 shows the claimed hardness properties. The composition of the coating is shown in Figures 2b and 2c.

[0042] The coating of the present invention from location 2 in FIG. 2 as well as the standard c-Al 66 Ti 34 N-coated and c-Ti 75 Si 25 For N coating, 10 s at temperatures of 800°C, 900°C, 1000°C, and 1100°C with an immersion time of 60 minutes. -5 Vacuum annealing experiments are performed in an electrothermal furnace with a background pressure of 0.05 Pa.

[0043] The hardness of the films has been measured using nanoindentation, and the structural evolution has been mapped using XRD as a function of different annealing temperatures.

[0044] FIG. 3(a) shows the c-Al of the present invention. 64 V 33 For Ti2Si1N alloy, and c-Al 66 Ti 34 N and c-Ti 75 Si 25 FIG. 1 shows the variation in hardness as a function of annealing temperature for N.

[0045] In addition, the standard c-Al 66 Ti 34 N-coated and c-Ti 75 Si 25 The N coating exhibits a decrease in hardness at annealing temperatures above 1000°C. 64 V 33 In the case of Ti2Si1N coatings, the hardness increases as a function of annealing temperature, an unusual and unknown property.

[0046] Figure 3(b) shows the evolution of the structure of the c-Al64V33Ti2Si1N of the present invention as a function of vacuum annealing. XRD shows that the wurtzite phase appears above the annealing temperature of 900 °C. TypeThe AlN phase transformation is shown. The alloy is shown to undergo the following reactions:

[0047] c-Al 64 V 33 Ti2Si1N--->c-TiVSiN+w-AlN (2) In the case of known TM-Al-N alloys, the precipitation of the w-AlN phase leads to a decrease in hardness, but surprisingly, in the case of the coating of the present invention, the hardness increases despite the precipitation of w-AlN.

[0048] The coatings were grown on an industrial scale on an Oerlikon Innova machine using cathodic arc in a nitrogen atmosphere at a pressure of 5 Pa, a substrate temperature of 400 °C, and a bias voltage of 70 V. During the arc discharge, a magnetic field of Mag 14 and an arc current of 200 A produced a burning voltage of 27 V.

[0049] In this example, the coating of the present invention was shown to be grown by combined arc deposition, but coatings having the same composition could be grown in thin film and bulk form by using the subject matter having the composition of the present invention in arc processes, sputtering processes and other related processes.

Claims

1. A microalloy comprising the elements Al, V and N, produced by a vapor deposition process; The microalloy contains, in addition to Al, V, and N, Ti and Si in amounts less than 5 at.% each; the microalloy comprises a cubic TiVSiN phase and a wurtzite AlN phase; the vapor deposition process is a physical vapor deposition process; High temperature stable ceramic coated structure.

2. 2. The coating structure of claim 1, wherein the high-temperature stable ceramic coating structure is formed as a metastable coating structure and annealed at a temperature above at least 900°C to form a multiphase morphology of cubic and wurtzite phases.

3. 3. The coating structure of claim 1 or 2, wherein the high-temperature stable ceramic coating structure is formed as a metastable coating structure and is annealed at a temperature of at least above 900°C to increase its hardness and / or wear resistance, and the increase in hardness and / or wear resistance is due to a phase transformation of the high-temperature stable ceramic coating structure.

4. The coating structure according to any one of claims 1 to 3, wherein the high-temperature stable ceramic coating structure has a layer thickness of less than 500 nm.

5. The coating structure according to any one of claims 1 to 4, wherein the high temperature stable ceramic coating structure is in thin film form or in bulk form.

6. The coating structure according to any one of claims 1 to 5, wherein the high temperature stable ceramic coating structure is formed as a multi-layer structure.

7. The microalloy is Al ６４ V ３３ Ti ２ Si １ The coating structure according to any one of claims 1 to 6, wherein the coating structure is formed as N.

8. The coating structure according to any one of claims 1 to 7, wherein the high-temperature stable ceramic coating structure further comprises oxides and / or carbides in addition to nitrides.

9. A vapor deposition process for producing a high temperature stable ceramic coated structure according to any one of claims 1 to 8, comprising: evaporating a target material containing the elements Al and V; and depositing the evaporated target material onto a suitable substrate.

10. 10. The vapor deposition process of claim 9, wherein different target materials are used, and the different target materials are evaporated simultaneously.

11. One of the target materials contains Al and V, ６５ V ３５ 11. The vapor deposition process of claim 10, comprising:

12. One of the target materials is Ti and Si, ７５ Si ２５ 12. The vapor deposition process of claim 10 or 11, wherein the ratio of 13. The vapor phase growth process of claim 9, wherein the substrate is a Co-containing substrate formed as WC-Co.

14. The vapor deposition process according to any one of claims 9 to 13, wherein the temperature of the substrate is 400°C.

15. A vapor deposition process according to any one of claims 9 to 14, wherein nitrogen is used as reactive coating gas.

16. The vapor deposition process of any one of claims 9 to 15, wherein a negative bias voltage is applied to the substrate during the coating process, said bias voltage being less than 75V.

17. The vapor deposition process according to any one of claims 9 to 16, wherein the coating process is formed as a HiPIMS or ARC PVD process.

18. A vapor deposition process according to any one of claims 9 to 17, wherein multiple layers of the high temperature stable ceramic coating structure according to any one of claims 1 to 8 are deposited on top of each other to form a multi-layer structure.

19. Use of the high-temperature stable ceramic coated structure according to any one of claims 1 to 8 for the manufacture of cutting and forming tools used in the automotive and / or aerospace industry.

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