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, coated by a PVD process and / or related process, for use at high temperatures exceeding 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" means cubic, "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. As a result, even a thin coating of just a few microns can significantly extend the lifespan 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 as hardness as a function of annealing temperature (as shown later in Figure 1), which represents the highest applicable temperature for these coatings.

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

[0006] The main problem, as shown in Figure 1, is that at annealing temperatures above 900°C, the metastable alloy decomposes into its respective ground states through the following reactions, resulting in a loss of hardness.

[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 above-described decrease in hardness caused by the phase transformation limits the application temperature of these coatings to a maximum temperature of 800°C for an exposure time as long as 100 hours and to a maximum temperature of 900°C for an exposure time as short as 1 hour.

[0010] For applications involving high annealing temperatures exceeding 900°C and long exposure times exceeding 100 hours, such applications may be, for example, in hot metal working or turbine tip sealant applications, and an excellent alloy is required in which a stable hardness is maintained at temperatures exceeding the annealing temperature of 900°C.

Summary of the Invention

Problems to be Solved by the Invention

[0011] Objective of the present invention An object of the present invention is to reduce or overcome one or more problems related to the prior art. In particular, an object of the present invention is to provide a hard, fracture-resistant, and oxidation-resistant coating structure that is stable at high temperatures and can be manufactured in an easy and cost-effective manner.

Means for Solving the Problems

[0012] Description of the present invention We investigated different alloy combinations and surprisingly found that AlVN alloys micro-alloyed with Ti and Si exhibit hardness anomalies that make these alloys 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 micro-alloy containing elements Al, V, and N and manufacturable by a vapor-phase growth process is disclosed.

[0014] The term "high-temperature stable coating structure" in the context of the present invention is understood to refer in particular to a structure that is stable over a long period of time up to a temperature of at least 800 °C, i.e., a structure that can be used at temperatures above 800 °C for a maximum of 100 hours without significantly losing its hardness.

[0015] In another example of the first aspect, the coating structure is formed as a metastable coating structure, which is in particular of wurtzite phase shape in cubic phase and is multilayered at temperatures above at least 900 °C.

[0016] In another example of the first aspect, the coating structure increases in hardness and / or wear resistance when the temperature exceeds 900 °C, and the increase in hardness and / or wear resistance is preferably related to a phase transformation of the coating structure, particularly based on the phase transformation of the coating structure.

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

[0018] In another example of the first aspect, the coating structure has a layer thickness smaller than 10 μm, preferably smaller than 1 μm, particularly smaller than 500 nm.

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

[0020] In another example of the first aspect, the microalloy contains only Al and V in addition to N, preferably with a ratio of Al to V such that Al 65 V 35 is included.

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

[0022] In other examples of the first embodiment, the microalloy comprises Al, V and N, Ti and Si, and the microalloy is preferably Al 64 V 33 It is formed as Ti2Si1N.

[0023] In other examples of the first embodiment, the coating structure further comprises oxides and / or carbides in addition to nitrides. According to the first embodiment of the present invention, the coating structure may also comprise silicides and / or borides.

[0024] In a second embodiment, a vapor phase growth process for manufacturing the aforementioned high-temperature stable ceramic coating structure is disclosed, and the vapor phase growth process is: A step of depositing a target material containing elements Al and V, The process includes the step of depositing the deposited target material onto a suitable substrate to form a high-temperature stable ceramic coating structure.

[0025] According to a second aspect of the present invention, the substrate can be formed as at least partially a metal compound.

[0026] In other examples 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 materials is Al and V, preferably Al 65 V 35 It contains in this ratio.

[0028] In another example of the second embodiment, one of the materials is Ti and Si, preferably Ti 75 Si25 It contains in this ratio.

[0029] In other examples of the second embodiment, a Co-containing substrate is used, which is formed in particular as WC-Co.

[0030] In other examples 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 other examples of the second embodiment, a reaction coating gas is used, preferably nitrogen. According to the second embodiment of the present invention, in addition to nitrogen, other gases such as argon or methane can be used as the reaction coating gas.

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

[0033] In other examples of the second embodiment, the coating process is formed as a PVD coating process, preferably as a sputtering process, and in particular as a HiPIMS or ARC PVD process.

[0034] In another example of the second embodiment, multiple layers of the aforementioned covering structure are deposited upon each other to form a multilayer structure.

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

[0036] The present invention will be described in detail below with reference to the drawings, based on examples. Detailed explanation [Brief explanation of the drawing]

[0037] [Figure 1] This figure shows the change in hardness as a function of annealing temperature for TiN and different TM-Al-N materials. [Figure 2] (a) shows a combined deposition chamber used to synthesize the coating of the present invention, (b) shows the composition of the coating of the present invention, and (c) shows the metal sublattice composition of the coating of the present invention. [Figure 3] (a) shows the change in hardness as a function of the annealing temperature of c-AlVTiSiN of the present invention, and (b) shows the X-ray diffraction pattern of c-AlVTiSiN as a function of the annealing temperature.

Mode for Carrying Out the Invention

[0038] FIG. 1 shows the change in hardness as a function of the annealing temperature of TiN and different TM-Al-N. As shown in FIG. 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 an annealing temperature exceeding 900°C as shown in FIG. 1. In contrast, the microalloy AlVN of the present invention shows an improvement in hardness as a function of the annealing temperature exceeding 900°C, as shown later in FIG. 3. Such hardness properties were reproducible.

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

[0040] FIG. 2(a) shows a combined deposition chamber used to synthesize the coating of the present invention, FIG. 2(b) shows the composition of the coating of the present invention, and FIG. 2(c) shows the metal sublattice composition of the coating of the present invention. According to the first embodiment, the alloy of the present invention is synthesized on a WC-Co substrate by a combined approach with objects having different chemical properties consisting of Al 65 V 35 and Ti 75 Si 25 The details of the deposition will be described below.

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

[0042] The coating of the present invention and standard cAl from position 2 in Figure 2. 66 Ti 34 N coating and c-Ti 75 Si 25 For the N coating, immersion time of 60 minutes at temperatures of 800°C, 900°C, 1000°C, and 1100°C was performed. -5 A vacuum annealing experiment will be conducted in an electric furnace with a background pressure of Pa.

[0043] The film hardness was measured using nanoindentation, and structural evolution was mapped using XRD as a function of different annealing temperatures.

[0044] Figure 3(a) shows the c-Al of the present invention. 64 V 33 Regarding Ti2Si1N alloy, and also c-Al 66 Ti 34 N and c-Ti 75 Si 25 This figure shows the change in hardness as a function of annealing temperature with respect to N.

[0045] Note that standard c-Al 66 Ti 34 N coating and c-Ti 75 Si 25 N coatings exhibit a decrease in hardness at annealing temperatures exceeding 1000°C. In contrast, the c-Al coating of the present invention... 64 V 33 In the case of Ti2Si1N coating, the hardness increases as a function of annealing temperature, which is an unusual and unknown property.

[0046] Figure 3(b) shows the c-Al function of the present invention according to this embodiment as a vacuum annealing function. 64 V 33This figure shows the structural changes of Ti2Si1N. XRD shows changes in the wurtzite AlN phase at temperatures above the annealing temperature of 900°C. 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 hardness decreases due to the precipitation of the w-AlN phase. Surprisingly, however, in the case of the coating of the present invention, the hardness increases despite the precipitation of w-AlN.

[0048] The coating was grown on an Oerlikon Innova machine using a cathode arc in a nitrogen atmosphere at an industrial scale, with a pressure of 5 Pa, a substrate temperature of 400°C, and a bias voltage of 70 V. During the arc discharge, a Mag14 magnetic field and an arc current of 200 A produced a combustion voltage of 27 V.

[0049] In this example, the coating of the present invention was shown to be grown by combination arc deposition, but coatings having the same composition could also be grown in thin film and bulk forms by using an object 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.

Images