High-load high-bonding alpha-ta / alpha-ta-n coating and method for preparing the same

Abstract

The application provides a high-load high-bonding-force alpha-Ta / alpha-Ta-N coating and a preparation method thereof, and relates to the field of physical vapor deposition. The alpha-Ta / alpha-Ta-N coating comprises a primer layer and an alternating layer, and the alternating layer is connected with the base body through the primer layer; the alternating layer is alternately composed of an alpha-Ta layer and an alpha-Ta-N layer, and the number of layers of the alternating layer is greater than or equal to 6; the crystal structures of the alpha-Ta layer and the alpha-Ta-N layer are both single body-centered cubic structures, the alpha-Ta-N layer has no columnar crystal characteristics and is a solid solution phase. Compared with the prior art, the application can obtain the alpha-Ta / alpha-Ta-N coating with high strength, high bonding force and high toughness through trace gas doping and simple alternating deposition under the conditions of low temperature, no expensive gas (only argon, nitrogen and hydrogen are used), no post heat treatment and no heterogeneous metal primer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of physical vapor deposition, in particular to a high load high bonding force alpha-Ta / alpha-Ta-N coating and a preparation method thereof. BACKGROUND

[0002] Bulk tantalum (Ta) metal has quite excellent physical and chemical properties: high melting point, high corrosion resistance, high ductility, excellent biocompatibility, etc. In the coating preparation process, Ta coating has two completely different crystal structures: body-centered cubic alpha-Ta and tetragonal beta-Ta. The former is the same as bulk Ta, with excellent ductility, but lower hardness and poor wear resistance. The latter has higher hardness, so it is considered by some researchers to have excellent prospects for wear resistance. However, in actual application and research, it is found that beta-Ta has extremely high brittleness, and its adjacent interface will become a weak point of the coating. Under the action of external force or internal stress of the coating, sudden brittle fracture may occur. At present, the academic circle basically reaches a consensus that alpha-Ta has more application prospects. However, it is still difficult to realize single alpha-Ta.

[0003] In view of the problem of soft alpha-Ta, some researchers propose to use Ta x N y compounds for alternating enhancement. However, the composition of Ta x N y compound is extremely complex, and more than ten kinds have been reported. Most of them have face-centered cubic, hexagonal close-packed or tetragonal structure. On the one hand, they all have relatively large brittleness, and on the other hand, the crystal structure is quite different from that of alpha-Ta. So far, due to the brittleness of the compound, the film-base bonding force and fracture toughness of the alternating coating cannot meet the requirements. How to realize the non-phase change and low brittleness strengthening of alpha-Ta has not been reported yet.

[0004] At the same time, alpha-Ta and beta-Ta will show columnar crystal characteristics during coating deposition, and will grow into thick columnar crystals under some processes. Continuous columnar grain boundaries are a kind of defects, on the one hand, continuous grain boundaries can provide a fast channel for the inward diffusion of oxidizing atmosphere, and on the other hand, they are easy to cause cracking of the coating under external force. Therefore, the through-type columnar crystal is not conducive to the use of the coating in oxidizing atmosphere and high load.

[0005] Due to the above problems, it is urgent to obtain a high load high toughness high bonding force alpha-Ta / alpha-Ta-N coating. SUMMARY

[0006] In view of the above problems, the present application provides a high load high bonding force alpha-Ta / alpha-Ta-N coating and a preparation method thereof.

[0007] A high load and high bonding force α-Ta / α-Ta-N coating, wherein,

[0008] 1) the α-Ta / α-Ta-N coating comprises a base layer and an alternating layer, the alternating layer being connected to the substrate through the base layer;

[0009] 2) the alternating layer is composed of α-Ta layers and α-Ta-N layers alternately, the number of layers of the alternating layer being ≥ 6;

[0010] 3) the α-Ta layers and the α-Ta-N layers are both single body-centered cubic structures, and the α-Ta-N layers are solid solution phases without columnar crystal characteristics.

[0011] Unlike the heterogeneous crystal structure Ta x N y ceramic layer widely adopted in the prior art, the α-Ta-N layers and the α-Ta layers in the present application have the same crystal structure type. The Ta-N layers are special solid solution phases with a higher nitrogen content than in the equilibrium phase diagram, and can achieve better comprehensive performance of hardness and plasticity.

[0012] Preferably, the grain size of the horizontal section of the columnar crystal of the α-Ta layer gradually increases from the direction close to the substrate to the direction away from the substrate, and the columnar crystal of the α-Ta layer is completely broken by the α-Ta-N layer and cannot extend to the α-Ta-N layer or the adjacent Ta layer. This feature indicates that the coating is in the "T zone" (non-uniform V-shaped grain structure throughout the film thickness) in the crystal structure of the film layer, in which region, on the one hand, the gap of the grain boundary is avoided, and on the other hand, the performance degradation caused by the thick columnar crystal is also avoided. At the same time, it is also in this crystal structure region that the breaking of the columnar crystal is more meaningful. The grain size in the horizontal and vertical directions can be controlled. For columnar crystals in other crystal structure regions, the grain breaking can only reduce the grain size in the vertical direction. For columnar crystals, it is more meaningful to reduce the grain size in the horizontal direction due to its special structure.

[0013] Preferably, the hardness of the α-Ta / α-Ta-N coating is 800-1800 HV, the scratch bonding force Lc2 is > 60 N, and the Vickers indentation of the coating under 10 kgf has no radial cracks.

[0014] Preferably, the lattice mismatch degree of the α-Ta layer and the α-Ta-N layer is < 3%. Smaller lattice mismatch degree will cause smaller interface energy, which will significantly reduce the local stability. It can effectively increase the bonding force and stability of the interlayer interface. Further, it can also enhance the synergistic deformation ability of the two layers.

[0015] Preferably, the N element content in the α-Ta-N layer is 1.0-9.9 at%. The suitable N element content is combined with a special preparation method in the present application, so that the N element in the coating layer is in a solid solution state (i.e. unsaturated, saturated and supersaturated), and the effect similar to that of martensite in steel is achieved through solid solution strengthening. While the original crystal structure is maintained, higher hardness is obtained. Maintaining the original crystal structure further ensures that the degree of lattice mismatch is small.

[0016] Preferably, the thickness ratio of the α-Ta layer to the Ta-N layer is (1-8):1, the hardness of the α-Ta layer is 500-750 HV, and the hardness of the Ta-N layer is 1500-2800 HV. The α-Ta layer with sufficient thickness ratio can absorb mechanical energy through elastic-plastic deformation when subjected to external force, slowing down the initiation and propagation of cracks. The suitable Ta-N layer can provide support capacity for the overall coating. If the proportion of the Ta-N layer is too large, the brittleness of the coating will be too large, thereby reducing the fracture toughness and bonding force of the coating; if the proportion of the Ta-N layer is too small, it cannot provide sufficient deformation resistance, thereby reducing the hardness.

[0017] Preferably, the crystallinity of the α-Ta-N layer is lower than that of the α-Ta layer. On the one hand, the N element can provide additional nucleation sites, so that the grain of the α-Ta-N layer is more refined. On the other hand, the addition of the N element causes distortion of the crystal lattice and increases the dislocation density, thereby affecting the crystallinity of this layer. The presence of local amorphous can further enhance the hardness of the α-Ta-N layer. The α-Ta-N layer in a solid solution state has a hardness similar to that of a compound phase.

[0018] The preparation method of the high-load high-bonding α-Ta / α-Ta-N coating layer as described above comprises the following steps:

[0019] S1, cleaning: using arc enhanced glow discharge (AEGD) to clean the substrate material by plasma;

[0020] S2, deposition of a primer layer: using high power impulse magnetron sputtering (HiPIMS) technology and direct current magnetron sputtering (DCMS) technology, a purity ≥99.95 wt% tantalum target is used to prepare a primer layer, the deposition atmosphere pressure is 0.5-1.0 Pa, the target peak power density is ≥1800 W / cm 2 ;

[0021] S3, alternating layer deposition: using HiPIMS superimposed DCMS technology, using a tantalum target with purity ≥ 99.95 wt% to prepare the coating body, the bias voltage is less than S2, the deposition atmosphere pressure is 0.5-1.0 Pa, the target peak power density is ≥ 1800 W / cm 2 .

[0022] Preferably, in S1, the temperature of the plasma cleaning is ≤ 200 ℃, the time is 5-20 min, the ratio of the anode current to the cathode current in AEGD is greater than 1, and the atmosphere is argon or a combination of argon and hydrogen. The plasma source of AEGD is farther away from the sample compared to other process methods, so that there is an ultra-high density of low-energy plasma near the substrate, which can achieve cleaning while reducing the risk of sparking. The cleaning of the substrate surface layer can be more conducive to the bottom layer to maintain the bcc lattice of the bulk material itself, and a single α-Ta can be obtained.

[0023] Preferably, in S2, the average current ratio of DCMS / HiPIMS is ≤ 0.8, the temperature is ≤ 200 ℃, the bias voltage is 400-1000 V, and the atmosphere is argon. The application combines HiPIMS and DCMS to increase the deposition rate while enhancing the plasma density. In combination with the pulse bias technology, the total particle energy striking the substrate surface per unit time can be increased, which helps to obtain a single α-Ta. The preferred ratio of DCMS and HiPIMS can ensure that the crystal type remains different from HiPIMS, while the total amount of ionized ions and the controllable increase of the deposition rate are increased.

[0024] Preferably, in S3, the average current ratio of DCMS / HiPIMS is ≤ 0.8, the temperature is ≤ 350 ℃, and the target-substrate distance is 80-100 mm.

[0025] Preferably, in S3, the deposition of Ta and Ta-N layers is achieved by adjusting the ratio of nitrogen and argon, the deposition atmosphere of the Ta layer is argon, and the deposition atmosphere of the Ta-N layer is a mixed atmosphere of argon and nitrogen.

[0026] Further preferably, in the mixed atmosphere of argon and nitrogen, the flow ratio of argon to nitrogen is 75:1-100:1. The lower nitrogen content combined with the ionization rate of DCMS / HiPIMS can achieve precise control of N element solid solution. A lower nitrogen concentration can also effectively prevent the formation of Ta-N compounds due to plasma nitriding.

[0027] Further preferably, the thickness of the α-Ta and α-Ta-N layers can be achieved by adjusting the time interval of nitrogen input, and the ratio of the time without nitrogen input to the time with nitrogen input is (1-8):1.

[0028] The technical key points and beneficial effects of the application are as follows:

[0029] (1) Low lattice mismatch design: through the design of single α-Ta and α-Ta-N solid solution, the adjacent layers have the same lattice type, and thus the low lattice mismatch between the layers is realized. Thus, the interfacial energy is low, and the stability and synergistic deformation ability are better.

[0030] (2) Preferred strengthening mode: Different from the traditional hard layer selected by ceramic phase or intermetallic phase heterogeneous strengthening. The present application realizes the strengthening mechanism of α-Ta-N layer through solid solution, fine grain, and local amorphous. The strength of the coating is enhanced while the plasticity and toughness of α-Ta are as much as possible. At the same time, through the optimization of columnar crystal type (the grain size gradually increases from bottom to top), the crystal size in horizontal and vertical directions is accurately controllable.

[0031] (3) Three-in-one of cleaning discharge form-deposition discharge form-deposition discharge atmosphere: Through AEGD, a highly clean surface is obtained, and through high bias and DCMS / HiPIMS, high energy flux is obtained, which cooperates to obtain single α-Ta of the primer layer. The high ionization rate of DCMS / HiPIMS cooperates with the discharge atmosphere with low N concentration, which realizes the controllable solid solubility and avoids the formation of surface nitride phase. At the same time, through the special form of ionization-bombardment, a higher temperature gradient than traditional nitriding is realized, which forms the effect of martensite-like phase change in steel, and realizes the supersaturated Ta-N solid solution. The three-in-one guarantees the controllable realization of the low lattice mismatch design and the preferred strengthening mode. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1 It is the XRD graph of Example 1;

[0034] Figure 2 It is the secondary electron phase of the cross-section of the coating of Example 1;

[0035] Figure 3 It is the cross-sectional HRTEM graph of Example 1;

[0036] Figure 4 It is the HRC indentation graph of Example 1 under 150 kgf;

[0037] Figure 5 It is the Vickers indentation of Example 1 under 10 kgf;

[0038] Figure 6 HRC indentation map at 150 kgf for Example 2;

[0039] Figure 7 Vickers indentation at 10 kgf for Example 2;

[0040] Figure 8 HRC indentation map at 150 kgf for Comparative Example 1;

[0041] Figure 9 HRC indentation map at 150 kgf for Comparative Example 2. DETAILED DESCRIPTION

[0042] To make the technical problems to be solved by the present application, technical solutions and advantages clearer, specific embodiments will be described in detail below with reference to the drawings.

[0043] Example 1

[0044] A high-load high-bonding α-Ta / α-Ta-N coating layer, comprising a primer layer and an alternating layer, the alternating layer being connected to the substrate through the primer layer;

[0045] The alternating layer is composed of α-Ta layers and α-Ta-N layers alternately, and the number of layers of the alternating layer is 18; the thickness of a single α-Ta layer is 1000 nm, and the thickness of a single α-Ta-N layer is 500 nm.

[0046] The preparation method of the high-load high-bonding α-Ta / α-Ta-N coating layer comprises the following steps:

[0047] S1, cleaning: plasma cleaning of the substrate material by AEGD technology; temperature 200 ℃, time 15 min, anode current 80 A, cathode current 70 A in AEGD, and the atmosphere is argon.

[0048] S2, primer layer deposition: using HiPIMS superimposed DCMS technology and a tantalum target with a purity of 99.99 wt% to prepare the primer layer, the deposition atmosphere pressure is 0.6 Pa, the target peak power density is 2600 W / cm 2 , the average current ratio of DCMS / HiPIMS is 0.5A:0.8A, the temperature is 200 ℃, the bias voltage is 500 V, and the atmosphere is argon.

[0049] S3, alternating layer deposition: using HiPIMS superimposed DCMS technology and a tantalum target with a purity of 99.99 wt% to prepare the coating body, the bias voltage is less than S2, the deposition atmosphere pressure is 0.65 Pa, and the target peak power density is 2600 W / cm 2The average current ratio of DCMS / HiPIMS is 0.5 A:0.8 A, the temperature is 200 ℃, the bias is 100 V, and the target-substrate distance is 90 mm. The deposition atmosphere of the α-Ta layer is argon, and the deposition atmosphere of the α-Ta-N layer is a mixed atmosphere of argon and nitrogen;

[0050] In S3, the deposition of the α-Ta and α-Ta-N layers is achieved by adjusting the ratio of nitrogen to argon (80:0 and 80:1). In the mixed atmosphere of argon and nitrogen, the flow ratio of argon to nitrogen is 80:1. The time without nitrogen is 10 min, and the time with nitrogen is 5 min.

[0051] Figure 1 The XRD pattern of the α-Ta / α-Ta-N coating prepared in Example 1 shows that the X-ray diffraction spectra of the α-Ta layer and the α-Ta-N layer are the same, and the crystal structures of the α-Ta layer and the α-Ta-N layer are both body-centered cubic structures.

[0052] Figure 2 The secondary electron phase of the cross-section of the coating of Example 1 is shown in the figure. The laterally continuous columnar region is the α-Ta layer, and the other region is the α-Ta-N layer. As shown in FIG. 2, the α-Ta layer is columnar crystal, and the α-Ta-N layer has no columnar crystal characteristics; the grain size of the horizontal section of the columnar crystal of the α-Ta layer gradually increases from the direction close to the substrate to the direction away from the substrate, and the columnar crystal of the α-Ta layer is completely broken by the α-Ta-N layer and does not extend to the α-Ta-N layer or the adjacent Ta layer; Figure 2

[0053] The hardness of the coating is tested according to GBT 4340.1-2009 "Metallic Materials Vickers Hardness Test Part 1: Test Method", and the adhesion of the coating is evaluated by the scratch method. The hardness of the α-Ta / α-Ta-N coating is 950 HV, and the scratch adhesion Lc2 is greater than 92 N.

[0054] Figure 3 The HRTEM image of the cross-section of Example 1 is taken as an example, and the HRTEM image of the α-Ta layer is shown in FIG. 3, in which the upper right corner is a local enlarged view, and the lower right corner is the inverse Fourier transform result of the local enlarged view. According to the calculation, Figure 3 the lattice mismatch degree of the α-Ta layer and the α-Ta-N layer is 1.4%.

[0055] The content of N element in the α-Ta-N layer is 8.2 at%.

[0056] The thickness ratio of the α-Ta layer to the α-Ta-N layer is 2:1, the hardness of the α-Ta layer is 550 HV, and the hardness of the α-Ta-N layer is 2650 HV.

[0057] The crystallinity of the α-Ta-N layer is lower than that of the α-Ta layer. ​

[0058] Figure 4 The 150 kgf HRC indentation map of the coating of Example 1 shows that there is no peeling of the coating around the 150 kgf HRC indentation, only radial cracks, and is rated as HF 1. Figure 5 The 10 kgf Vickers indentation of Example 1 shows that there is no radial crack of the 10 kgf Vickers indentation of the coating.

[0059] Example 2

[0060] The difference from Example 1 is that:

[0061] The alternating layer is alternately composed of an α-Ta layer and an α-Ta-N layer, and the number of layers of the alternating layer is 20; the single-layer thickness of the α-Ta layer is 1000 nm, and the single-layer thickness of the α-Ta-N layer is 250 nm.

[0062] In the S3 alternating layer deposition step: the coating body is prepared by using the HiPIMS superimposed DCMS technology and a tantalum target with a purity of 99.96 wt%; the deposition atmosphere pressure is 0.68 Pa, and the α-Ta-N layer deposition atmosphere is a mixed atmosphere of argon and nitrogen; in the mixed atmosphere of argon and nitrogen, the flow ratio of argon to nitrogen is 85:1. The time without nitrogen input is 10 min, and the time with nitrogen input is 2.5 min.

[0063] The hardness of the α-Ta / α-Ta-N coating is 850 HV, and the scratch adhesion L c2 > 89 N.

[0064] The lattice mismatch degree of the α-Ta layer and the α-Ta-N layer is 1.35%.

[0065] Through EDS testing, the content of N element in the α-Ta-N layer is 7.9 at%.

[0066] The thickness ratio of the α-Ta layer to the α-Ta-N layer is 4:1.

[0067] As shown in Figure 6 and Figure 7 The 150 kgf HRC indentation map of the coating of Example 1 shows that there is no peeling of the coating around the 150 kgf HRC indentation, only radial cracks, and is rated as HF 1, and the 10 kgf Vickers indentation of the coating has no radial crack.

[0068] Example 3

[0069] The difference from Example 1 is that:

[0070] The alternating layer is alternately composed of an α-Ta layer and an α-Ta-N layer, and the number of layers of the alternating layer is 48; the single-layer thickness of the α-Ta layer is 125 nm, and the single-layer thickness of the α-Ta-N layer is 125 nm.

[0071] In the S2 primer layer deposition step: deposition atmosphere pressure 0.8 Pa, target peak power density 2100 W / cm 2 The time for no nitrogen gas input and for nitrogen gas input was 2 min.

[0072] The α-Ta / α-Ta-N coating hardness was 1025 HV, and the scratch method bonding force L c2 > 70 N.

[0073] The thickness ratio of the α-Ta layer and the α-Ta-N layer was 1:1.

[0074] There was no peeling around the HRC indentation under 150 kgf, only radial cracks, rated as HF 1, and there were no radial cracks in the 10 kgf Vickers indentation of the coating.

[0075] Example 4

[0076] The difference from Example 1 is that:

[0077] The alternating layer was composed of alternating α-Ta layers and α-Ta-N layers, and the number of layers of the alternating layer was 24; the single-layer thickness of the α-Ta layer was 250 nm, and the single-layer thickness of the α-Ta-N layer was 250 nm. The time for no nitrogen gas input and for nitrogen gas input was 2.5 min.

[0078] The α-Ta / α-Ta-N coating hardness was 1150 HV, and the scratch method bonding force L c2 > 65 N.

[0079] The thickness ratio of the α-Ta layer and the α-Ta-N layer was 1:1.

[0080] There was no peeling around the HRC indentation under 150 kgf, only radial cracks, rated as HF 1, and there were no radial cracks in the 10 kgf Vickers indentation of the coating.

[0081] Example 5

[0082] The difference from Example 1 is that:

[0083] The alternating layer was composed of alternating α-Ta layers and α-Ta-N layers, and the number of layers of the alternating layer was 6; the single-layer thickness of the α-Ta layer was 2000 nm, and the single-layer thickness of the α-Ta-N layer was 2000 nm.

[0084] In the S3 alternating layer deposition step: target peak power density 3000 W / cm 2 ; the ratio of nitrogen gas to argon gas for the α-Ta-N layer was 75:1. The time for no nitrogen gas input and for nitrogen gas input was 18 min.

[0085] The α-Ta / α-Ta-N coating has a hardness of 875 HV, and a scratch method bonding force L c2 >81 N.

[0086] The thickness ratio of the α-Ta layer and the α-Ta-N layer is 1:1.

[0087] There is no peeling of the coating around the HRC indentation under 150 kgf, only radial cracks, and the evaluation is HF 1, and there is no radial crack of the 10 kgf Vickers indentation of the coating.

[0088] Example 6

[0089] The difference from Example 1 is that:

[0090] The alternating layer is alternately composed of an α-Ta layer and an α-Ta-N layer, and the number of layers of the alternating layer is 60.

[0091] In S1, the atmosphere is a combination of argon and hydrogen.

[0092] In S2, the base layer is deposited: the deposition atmosphere pressure is 0.8 Pa, the bias voltage is 600 V, the target peak power density is 2000 W / cm 2 ;

[0093] In S3, the alternating layer is deposited: the deposition atmosphere pressure is 0.8 Pa, the target peak power density is 2400 W / cm 2 ; The flow ratio of argon and nitrogen in the mixed atmosphere of argon and nitrogen is 90:1. The target-substrate distance is 85 mm.

[0094] The α-Ta / α-Ta-N coating has a hardness of 860 HV, and a scratch method bonding force L c2 >80 N.

[0095] The thickness ratio of the α-Ta layer and the α-Ta-N layer is 1:1.

[0096] There is no peeling of the coating around the HRC indentation under 150 kgf, only radial cracks, and the evaluation is HF 1, and there is no radial crack of the 10 kgf Vickers indentation of the coating.

[0097] Comparative Example 1

[0098] In order to further embody the beneficial effects of the scheme of the present application, the inventors list typical comparative examples here;

[0099] The difference from Example 1 is that:

[0100] The alternating layer is alternately composed of an α-Ta layer and an α-Ta-N layer, and the number of layers of the alternating layer is 10; the single-layer thickness of the α-Ta layer is 1000 nm, and the single-layer thickness of the α-Ta-N layer is 1500 nm.

[0101] The α-Ta / α-Ta-N coating has a hardness of 1200 HV and a scratch adhesion strength of L. c2 ~58 N.

[0102] The thickness ratio of the α-Ta layer to the α-Ta-N layer is 1:1.5.

[0103] like Figure 8 As shown, radial cracks and significant peeling appeared in the coating around the HRC indentation at 150 kgf, which can be rated as HF 4 according to VDI 3198 criteria. Because the thickness ratio of the α-Ta layer to the α-Ta-N layer does not conform to the specifications of this invention, it exhibits worse adhesion and load-bearing capacity compared to all the aforementioned embodiments.

[0104] Comparative Example 2

[0105] To further demonstrate the beneficial effects of the proposed solution, the inventors have provided typical comparative examples here.

[0106] The difference from Example 1 is as follows:

[0107] In the mixed atmosphere of argon and nitrogen, the flow rate ratio of argon to nitrogen is 30:1.

[0108] The α-Ta / α-Ta-N coating has a hardness of 1180 HV and a scratch adhesion strength of L. c2 ~52 N.

[0109] Radial cracks and significant peeling appeared in the coating around the HRC indentation at 150 kgf, which, according to VDI 3198 criteria, can be rated as HF 3. Figure 9 As shown, radial and circumferential cracks appeared in the 10 kgf Vickers indentation of the coating, and the fracture toughness was significantly reduced. Because the argon to nitrogen flow ratio of 30:1 did not conform to the specifications of this invention, trace amounts of nitride (FCC-TaN) were precipitated. The change in crystal structure led to a significant increase in lattice mismatch, resulting in poorer adhesion and load-bearing capacity compared to all the aforementioned embodiments.

[0110] Comparative Example 3

[0111] To further demonstrate the beneficial effects of the proposed solution, the inventors have provided typical comparative examples here.

[0112] The difference from Example 1 is as follows:

[0113] In the mixed atmosphere of argon and nitrogen, the flow ratio of argon to nitrogen is 1:1;

[0114] The Ta-N layer is a single δ-TaN phase with a hardness of 3500 HV;

[0115] The α-Ta / α-Ta-N coating hardness 1805 HV, scratch adhesion L c2 42 N.

[0116] HRC indentation around the coating under 150 kgf radial cracks and obvious peeling, according to VDI 3198 criteria, can be assessed as HF 4. The coating 10 kgf Vickers indentation appears obvious radial cracks. Because the hardness of Ta-N layer hardness is too high, beyond the set of the present invention, the difference between the adjacent two layers when subjected to deformation is too large, and then form a larger interface stress, inducing the initiation and propagation of cracks. Compared to all the previous examples have a worse binding force and carrying capacity.

[0117] The above, only for the specific embodiments of the present application, but the scope of protection of the present application is not limited to this, any skilled in the art of the technical personnel in the technical range of the present application disclosed, can easily think of changes or replacement, should be covered within the scope of protection of the present application. Therefore, the scope of protection of the present application should be subject to the scope of protection of the claims.

Claims

1. A high-load-bearing and high-adhesion α-Ta / α-Ta-N coating, characterized in that, 1) The α-Ta / α-Ta-N coating includes an underlayer and an alternating layer, wherein the alternating layer is connected to the substrate through the underlayer; 2) The alternating layers are composed of alternating α-Ta layers and α-Ta-N layers, and the number of alternating layers is ≥6; 3) The crystal structures of the α-Ta layer and the α-Ta-N layer are both single body-centered cubic structures. The α-Ta-N layer has no columnar crystal characteristics and is a solid solution phase. The N element content in the α-Ta-N layer is 1.0 to 9.9 at%.

2. The high load-bearing and high adhesion α-Ta / α-Ta-N coating according to claim 1, characterized in that, The grain size of the columnar crystals in the horizontal cross section of the α-Ta layer gradually increases from the direction close to the substrate to the direction far from the substrate, and the columnar crystals of the α-Ta layer are completely broken by the α-Ta-N layer and do not extend to the α-Ta-N layer or the adjacent Ta layer.

3. The high load-bearing and high-adhesion α-Ta / α-Ta-N coating according to claim 1 or 2, characterized in that, The α-Ta / α-Ta-N coating has a hardness of 800-1800 HV, a scratch bonding force Lc2 > 60 N, and no radial cracks in the Vickers indentation of the coating at 10 kgf.

4. The high load-bearing and high-adhesion α-Ta / α-Ta-N coating according to claim 1 or 2, characterized in that, The lattice mismatch between the α-Ta layer and the α-Ta-N layer is <3%, and the crystallinity of the α-Ta-N layer is lower than that of the α-Ta layer.

5. The high load-bearing and high-adhesion α-Ta / α-Ta-N coating according to claim 1 or 2, characterized in that, The thickness ratio of the α-Ta layer to the Ta-N layer is (1-8):1, the hardness of the α-Ta layer is 500-750 HV, and the hardness of the Ta-N layer is 1500-2800 HV.

6. The method for preparing the high load-bearing and high-adhesion α-Ta / α-Ta-N coating according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Cleaning: Plasma cleaning of the substrate material is performed using arc-enhanced glow discharge technology; S2. Underlayer Deposition: High-power pulsed magnetron sputtering combined with DC magnetron sputtering is used to prepare the underlayer using a tantalum target with a purity ≥99.95wt%. The deposition atmosphere pressure is 0.5–1.0 Pa, and the target peak power density is ≥1800 W / cm³. 2 ; S3, Alternating Layer Deposition: High-power pulsed magnetron sputtering combined with DC magnetron sputtering is used to prepare the coating substrate with a tantalum target of ≥99.95wt% purity. The bias voltage is less than that of S2, the deposition atmosphere pressure is 0.5–1.0 Pa, and the target peak power density is ≥1800 W / cm³. 2 .

7. The method for preparing the high load-bearing and high-adhesion α-Ta / α-Ta-N coating according to claim 6, characterized in that, In S1, the plasma cleaning temperature is ≤200℃, the time is 5~20min, the ratio of anode current to cathode current in arc-enhanced glow discharge technology is greater than 1, and the atmosphere is argon or a combination of argon and hydrogen.

8. The method for preparing the high load-bearing and high-adhesion α-Ta / α-Ta-N coating according to claim 6, characterized in that, In S2, the average current ratio of DC magnetron sputtering to high-power pulsed magnetron sputtering is ≤0.8, the temperature is ≤200℃, the bias voltage is 400~1000V, and the atmosphere is argon.

9. The method for preparing the high load-bearing and high-adhesion α-Ta / α-Ta-N coating according to claim 6, characterized in that, In S3, the average current ratio of DC magnetron sputtering to high-power pulsed magnetron sputtering is ≤0.8, the temperature is ≤350℃, the bias voltage is 0~300V, and the target-substrate distance is 80~100mm.

10. The method for preparing the high-load-bearing and high-adhesion α-Ta / α-Ta-N coating according to claim 9, characterized in that, In S3, the deposition of Ta and Ta-N layers is achieved by adjusting the ratio of nitrogen to argon. The deposition atmosphere of the Ta layer is argon, and the deposition atmosphere of the Ta-N layer is a mixture of argon and nitrogen.

11. The method for preparing the high load-bearing and high-adhesion α-Ta / α-Ta-N coating according to claim 10, characterized in that, In the mixed atmosphere of argon and nitrogen, the flow rate ratio of argon to nitrogen is 75:1-100:1.

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