Wide-temperature-range lubricating TiAlVAgN composite coating and preparation method thereof

Abstract

The present application relates to a kind of wide temperature range lubricating TiAlVAgN composite coating and its preparation method, the composite coating includes sequentially deposited on the surface of substrate (1) TiN primer layer (2), TiAlN transition layer (3), TiAlVN intermediate layer (4) and TiAlVAgN layer (5), the total thickness of the composite coating is 3.5 ~ 5.5 μm;The method is prepared by cathodic arc ion plating process composite coating, including cleaning target material, TiN primer layer (2) preparation, TiAlN transition layer (3) preparation, TiAlVN intermediate layer (4) preparation, TiAlVAgN layer (5) preparation and vacuum environment heat preservation.Compared with prior art, the toughness of the composite coating of the present application is further improved, so that it can realize lubrication under the working environment from room temperature to 800 DEG C while maintaining good wear resistance, applied to coating bearing makes the service life of coating bearing be further improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of physical vapor deposition coating and friction protection, and relates to a wide-temperature-range lubricating TiAlVAgN composite coating and a preparation method thereof. BACKGROUND

[0002] Wear and material damage caused by friction result in huge economic losses, and the development of wear-resistant and friction-reducing materials and material protection processes has become a key breakthrough point. As a kind of material surface wear-resistant and protective material, hard ceramic-based coating is widely used in the industry of cutting tools and automobile parts. However, with the increasingly harsh service environment, people gradually realize that the high hardness and high oxidation resistance of ceramic-based coating are not enough, and its lubrication under high speed and high load conditions is particularly important. If the hard ceramic-based coating produces microcracks due to friction, vibration and impact, and the cracks expand along the grain boundaries, the coating will be broken and further damage the workpiece as debris, causing an incalculable loss.

[0003] TiAlN-based ceramic coating has high hardness, corrosion resistance and oxidation resistance, and can meet the use requirements in extreme environments, and is rapidly developed and widely used in the engineering field. However, the inherent brittleness of ceramic coating makes it prone to serious wear and fracture under high load, and the chemical inertness of the surface of the ceramic coating affects the adsorption performance of the lubricant, making it difficult to form a stable lubricating oil film, and the lubrication effect varies greatly with different materials and structures of the friction pair.

[0004] Patent CN114703454A discloses a wide-temperature-range wear-resistant and self-lubricating CrVN / Ag composite coating and a preparation method thereof. The composite coating comprises a bonding layer, a gradient layer and a wear-resistant and self-lubricating surface layer. The bonding layer is a Cr layer, the gradient layer comprises a CrN layer, a CrVN layer and a CrVN / Ag layer, and the wear-resistant and self-lubricating surface layer comprises a nitride ceramic phase and an Ag phase. The nitride ceramic phase comprises VN and CrN. However, the coating prepared by the patent has low hardness and a large friction coefficient, and the value is greater than 0.6. SUMMARY

[0005] The purpose of the present application is to overcome at least one of the defects of the prior art, and to provide a wide-temperature-range lubricating TiAlVAgN composite coating and a preparation method thereof. The composite coating of the present application has further improved toughness, so that it can realize lubrication under working conditions from room temperature to 800 DEG C while maintaining good wear resistance, and when applied to a coated bearing, the service life of the coated bearing is further improved.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] One of the technical solutions of the present application is to provide a wide temperature range lubricating TiAlVAgN composite coating, which comprises a TiN primer layer, a TiAlN transition layer, a TiAlVN intermediate layer and a TiAlVAgN layer deposited on the surface of the substrate in sequence, and the total thickness of the composite coating is 3.5-5.5 microns.

[0008] Further, the thickness of the TiN primer layer is 0.2-0.4 microns, the thickness of the TiAlN transition layer is 0.4-0.6 microns, the thickness of the TiAlVN intermediate layer is 0.4-0.6 microns, and the thickness of the TiAlVAgN layer is 2.5-3.9 microns.

[0009] One of the technical solutions of the present application is to provide a preparation method of a wide temperature range lubricating TiAlVAgN composite coating, which is prepared by a cathodic arc ion plating process, comprising the following steps:

[0010] (1) Cleaning the target material: pre-evacuating, setting the furnace cavity temperature, introducing inert gas, and self-cleaning of the Ti target, AlTi target, TiAlV target and TiAlAg target;

[0011] (2) TiN primer layer preparation: controlling the vacuum degree and the furnace cavity temperature, connecting the Ti target to the current, introducing the reaction gas, and depositing to obtain the TiN primer layer;

[0012] (3) TiAlN transition layer preparation: controlling the vacuum degree and the furnace cavity temperature, connecting the AlTi target to the current, introducing the reaction gas, and depositing to obtain the TiAlN transition layer;

[0013] (4) TiAlVN intermediate layer preparation: controlling the vacuum degree and the furnace cavity temperature, connecting the AlTiV target to the current, introducing the reaction gas, and depositing to obtain the TiAlVN intermediate layer;

[0014] (5) TiAlVAgN layer preparation: controlling the vacuum degree and the furnace cavity temperature, connecting the AlTiV target to the current, connecting the AlTiAg target to the current, introducing the reaction gas, and depositing to obtain the TiAlVAgN layer;

[0015] (6) Vacuum environment heat preservation: controlling the vacuum degree and the furnace cavity temperature, and heat preservation.

[0016] Further, the substrate is pretreated before step (1): polishing the substrate, ultrasonic oscillation, blowing dry after cleaning, and rotating in the plating chamber;

[0017] The polishing mesh number is 2400-3000 meshes, the ultrasonic oscillation time is 8-10 minutes, and the cleaning time is 5-7 minutes.

[0018] As a preferred technical scheme, the polishing adopts sandpaper or cotton cloth wheel, the ultrasonic oscillation is sequentially performed in acetone and ethanol, the cleaning adopts water, and the blow-drying adopts dry air or dry nitrogen.

[0019] Further, the vacuum degree in step (1) is 1x10 -3 ~ 3x10 -3 Pa, and the furnace cavity temperature is 360~400℃.

[0020] The inert gas flow is 160~200sccm.

[0021] The Ti target, AlTi target, TiAlV target and TiAlAg target current are all 120~140A, and the cleaning time is 5~8min.

[0022] As a preferred technical scheme, the inert gas in step (1) is argon.

[0023] Further, the vacuum degree in step (2) is 1x10 -1 ~ 3x10 -1 Pa, and the furnace cavity temperature is 360~400℃.

[0024] The Ti target current is 120~140A.

[0025] The reaction gas is nitrogen, and the flow is 160~200sccm.

[0026] The deposition bias is -120~-100V, and the time is 10~15min.

[0027] Further, the vacuum degree in step (3) is 1x10 -1 ~ 3x10 -1 Pa, and the furnace cavity temperature is 360~400℃.

[0028] The AlTi target current is 110~130A.

[0029] The reaction gas is nitrogen, and the flow is 120~150sccm.

[0030] The deposition bias is -100~-80V, and the time is 20~25min.

[0031] Further, the vacuum degree in step (4) is 1x10 -1 ~ 3x10 -1 Pa, and the furnace cavity temperature is 360~400℃.

[0032] The AlTiV target current is 130~150A.

[0033] The reaction gas is nitrogen, and the flow is 120~150sccm.

[0034] The deposition bias voltage is -110 to -90V, and the time is 18 to 24 min.

[0035] Further, the vacuum degree in step (5) is 1x10 -1 ~ 3x10 -1 Pa, and the furnace cavity temperature is 360 to 400 DEG C.

[0036] The AlTiV target current is 120 to 140A, and the AlTiAg target current is 150 to 180A.

[0037] The reaction gas is nitrogen, and the flow rate is 180 to 210sccm.

[0038] The deposition bias voltage is -120 to -90V, and the time is 60 to 100 min.

[0039] Further, the vacuum degree in step (6) is 1x10 -4 ~ 3x10 -4 Pa, and the furnace cavity temperature is 400 to 450 DEG C.

[0040] The holding time is 120 to 150 min.

[0041] The coating gradient design can reduce the difference in the thermal expansion coefficient between the interval layers, and the intermediate layer can play a moderating role; when receiving external impact or fatigue force, the intermediate layer plays a transitional role, and the comprehensive performance of the coating can be effectively improved. At the same time, the coating contains TiN, AlN and a solid solution phase formed by the two phases, so the hardness of the coating is high.

[0042] The present application adopts the design of TiN / TiAlN / TiAlVN / TiAlVAgN multilayer structure, follows the principle of gradually reducing the difference in the thermal expansion coefficient, and after the coating deposition is completed, the coating is held in a vacuum condition, so that the defects in the coating are recovered and the stress is released, and therefore the internal stress of the film layer is low and the toughness of the coating is good.

[0043] Compared with the prior art, the present application has the following advantages:

[0044] (1) The composite coating of the present application is obtained by reducing the difference in the thermal expansion coefficient between the layers, and after the preparation is completed, the toughness of the coating is further improved, so that it can realize lubrication in the working environment from room temperature to 800 DEG C while maintaining good wear resistance;

[0045] (2) Compared with TiAlN and TiAlVN coatings, the composite coating of the present application has Ag nanocrystals in the coating, so that it has good ductility and high lubricity at low temperature;

[0046] (3) Compared with TiAlN and TiAlAgN coatings, the V element in the coating generates layered V2O5 at high temperature, the oxide has low shear resistance and can play a lubricating effect on the friction section;

[0047] (4) The present application has obvious advantages in coating wear resistance, lubricity and stress release, and can significantly improve the service life of the coating bearing. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 The structure diagram of the wide-temperature-range lubricating TiAlVAgN composite coating in the embodiment of the present application is shown.

[0049] Figure 2 The friction coefficient comparison chart of the coating bearing workpiece under the series temperature environment in the embodiment of the present application and comparative examples 5 to 8 is shown.

[0050] Mark explanation in the figure:

[0051] 1 - substrate, 2 - TiN primer layer, 3 - TiAlN transition layer, 4 - TiAlVN intermediate layer, 5 - TiAlVAgN layer. DETAILED DESCRIPTION

[0052] The present application will be described in detail below in combination with specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present application, and detailed implementation and specific operation process are given, but the protection scope of the present application is not limited to the following examples.

[0053] The equipment used in the following examples is conventional in the art unless otherwise specified; the reagents used are commercially available or prepared by conventional methods in the art unless otherwise specified; and the following examples that are not described in detail can be achieved by conventional experimental means in the art.

[0054] The purity of the Ti target, AlTi target, AlTiV target and AlTiAg target used in the present embodiment is greater than 99.8%.

[0055] Embodiment:

[0056] A wide-temperature-range lubricating TiAlVAgN composite coating and a preparation method thereof, the specific steps are as follows:

[0057] (1) Pretreatment of substrate 1: the substrate 1 polished with 2400 mesh sandpaper is sequentially ultrasonically oscillated in acetone and anhydrous ethanol for 8 min, washed with deionized water for 5 min, and then dried with dry air and placed in a plating chamber for self-rotation;

[0058] (2) Clean the target material: pre-evacuate to 1×10 -3Pa, the furnace cavity temperature is 380℃, 180sccm of argon is introduced, the Ti target, the AlTi target, the TiAlV target and the TiAlAg target are self-cleaned at 120A current for 6min;

[0059] (3) TiN primer layer 2 preparation: vacuum degree 1x10 -1 Pa, the furnace cavity temperature is 380℃, the Ti target is connected to 130A current, 180sccm of nitrogen is introduced, and TiN primer layer 2 is obtained by depositing at-120V bias for 12min, with a thickness of 0.3μm;

[0060] (4) TiAlN transition layer 3 preparation: vacuum degree 1x10 -1 Pa, the furnace cavity temperature is 380℃, the AlTi target is connected to 110A current, 120sccm of nitrogen is introduced, and TiAlN transition layer 3 is obtained by depositing at-100V bias for 20min, with a thickness of 0.5μm;

[0061] (5) TiAlVN intermediate layer 4 preparation: vacuum degree 1x10 -1 Pa, the furnace cavity temperature is 380℃, the AlTiV target is connected to 140A current, 130sccm of nitrogen is introduced, and TiAlVN intermediate layer 4 is obtained by depositing at-90V bias for 22min, with a thickness of 0.5μm;

[0062] (6) TiAlVAgN layer 5 preparation: vacuum degree 1x10 -1 Pa, the furnace cavity temperature is 380℃, the AlTiV target is connected to 120A current, the AlTiAg target is connected to 160A current, 180sccm of nitrogen is introduced, and TiAlVAgN layer 5 is obtained by depositing at-110V bias for 80min, with a thickness of 3.1μm;

[0063] (7) vacuum environment heat preservation: vacuum degree 2x10 -4 Pa, the furnace cavity temperature is 420℃, and heat preservation is performed for 120min.

[0064] As shown in Figure 1 the embodiment, the TiAlVAgN composite coating prepared in the embodiment is composed of TiN primer layer 2, TiAlN transition layer 3, TiAlVN intermediate layer 4 and TiAlVAgN layer 5 deposited on the surface of the substrate 1 in sequence, and the principle of gradually reducing the difference in thermal expansion coefficient is followed. In addition, the coating is heat preserved for 120min under vacuum condition after the deposition of the coating is completed, so that the defects in the coating are recovered and the stress is released, and therefore the stress in the film layer is low and the toughness of the coating is good.

[0065] Comparative Example 1:

[0066] A TiAlN composite coating, the preparation method is the same as steps (1) to (4) in Example 1.

[0067] Comparative Example 2:

[0068] A TiAlVN composite coating, the preparation method is the same as steps (1) to (5) in Example 1.

[0069] Comparative Example 3:

[0070] A TiAlAgN composite coating, the coating preparation method is basically the same as steps (1) to (6) in Example 1, except that the AlTiV target is not opened.

[0071] Comparative Example 4:

[0072] A TiAlAgN composite coating, the coating preparation method is the same as steps (1) to (6) in Example 1, and step (7) is not performed.

[0073] Stress test of a composite coating, the specific steps are as follows:

[0074] Using the curvature method, using the stoney formula to calculate. The substrate is a single crystal silicon wafer with a length of 40mm and a width of 6mm, and the formula is as follows:

[0075]

[0076] Where, E s and V s are the elastic modulus and Poisson's ratio of the substrate, t s and t f are the thicknesses of the substrate and the film, and R is the radius of curvature of the substrate.

[0077] The internal stress of the TiAlVAgN coating is -0.68GPa, which is lower than that of the TiAlN coating -3.5GPa, the TiAlVN coating -3.8GPa, the TiAlAgN coating -2.1GPa, and the TiAlVAgN coating without heat preservation -2.6GPa. The low internal stress can be attributed to the following points: the gradient multilayer structure design, which is beneficial to stress release through the interface movement between layers; the nitride phase in the internal structure of the coating and the Ag nanocrystalline crystal slip, which releases stress; Ag nanocrystalline has high ductility, which is beneficial to stress release; After the coating is completed, the coating internal defects are recovered, which is beneficial to stress release.

[0078] Comparative Example 5:

[0079] A bearing, no coating.

[0080] Comparative Example 6:

[0081] A bearing is coated with a TiAlN composite coating, and the coating preparation method is the same as steps (1) to (4) in Example 1.

[0082] Comparative Example 7:

[0083] A bearing is coated with a TiAlVN composite coating, and the coating preparation method is the same as steps (1) to (5) in Example 1.

[0084] Comparative Example 8:

[0085] A bearing is coated with a TiAlAgN composite coating. The coating preparation method is basically the same as steps (1) to (6) in Example 1, except that the AlTiV target is not opened.

[0086] The specific steps for testing the abrasion resistance of a composite coating are as follows:

[0087] The UMT-3 friction testing machine was used to test the tribological properties of coatings under a series of temperature environments (room temperature, 200℃, 400℃, 600℃, and 800℃). The friction method was ball-disc, using Si3N4 ceramic balls with a diameter of 9.5mm as the friction pair. The load was 10N, the rotation speed was 200r / min, the wear scar diameter was 10mm, and the friction time was 10min. The friction coefficient values ​​at the stable wear stage were compared.

[0088] like Figure 2 As shown, the coefficient of friction of coated workpieces is lower than that of uncoated workpieces. Among them, the coefficient of friction of TiAlN coated workpieces is only lower than that of uncoated workpieces. Below 400℃, TiAlAgN coating exhibits a lower coefficient of friction, while the coefficient of friction of TiAlVN coating decreases above 400℃. TiAlVAgN coating exhibits the lowest coefficient of friction and the best lubrication from room temperature to 800℃.

[0089] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A wide-temperature-range lubricating TiAlVAgN composite coating, characterized in that, The composite coating comprises a TiN base layer (2), a TiAlN transition layer (3), a TiAlVN intermediate layer (4), and a TiAlVAgN layer (5) sequentially deposited on the surface of a substrate (1), with a total thickness of 3.5~5.5 μm. The thickness of the TiN base layer (2) is 0.2~0.4 μm, the thickness of the TiAlN transition layer (3) is 0.4~0.6 μm, the thickness of the TiAlVN intermediate layer (4) is 0.4~0.6 μm, and the thickness of the TiAlVAgN layer (5) is 2.5~3.9 μm; The wide-temperature-range lubricating TiAlVAgN composite coating is prepared by a method including the following steps: the composite coating is prepared by cathodic arc ion plating. (1) Cleaning the target material: pre-vacuum, set the furnace temperature, and introduce inert gas. Ti target, AlTi target, TiAlV target and TiAlAg target are self-cleaning. (2) Preparation of TiN substrate (2): Control the vacuum degree and furnace temperature, apply current to Ti target, introduce reaction gas, deposit, and obtain TiN substrate (2). (3) Preparation of TiAlN transition layer (3): Control the vacuum degree and furnace temperature, apply current to AlTi target, introduce reaction gas, deposit, and obtain TiAlN transition layer (3). (4) Preparation of TiAlVN intermediate layer (4): Control the vacuum degree and furnace temperature, apply current to AlTiV target, introduce reaction gas, deposit, and obtain TiAlVN intermediate layer (4). (5) Preparation of TiAlVAgN layer (5): Control the vacuum degree and furnace temperature, AlTiV target access current, AlTiAg target access current, introduce reaction gas, deposit, and obtain TiAlVAgN layer (5). (6) Vacuum environment insulation: control the vacuum level and furnace temperature, and maintain the temperature; In step (2), the Ti target current is 120~140 A; The reactant gas is nitrogen, with a flow rate of 160~200 sccm; The deposition bias voltage was -120 to -100 V, and the time was 10 to 15 min. In step (3), the AlTi target current is 110~130 A; The reactant gas is nitrogen, with a flow rate of 120~150 sccm; The deposition bias voltage was -100 to -80 V, and the time was 20 to 25 min. In step (4), the AlTiV target current is 130~150 A; The reactant gas is nitrogen, with a flow rate of 120~150 sccm; The deposition bias voltage was -110 to -90 V, and the time was 18 to 24 min. In step (5), the AlTiV target current is 120~140 A, and the AlTiAg target current is 150~180 A; The reactant gas is nitrogen, with a flow rate of 180~210 sccm; The deposition bias voltage was -120 to -90 V, and the time was 60 to 100 min.

2. The wide-temperature-range lubricating TiAlVAgN composite coating according to claim 1, characterized in that, Step (1) Pretreatment of substrate (1): Polish the substrate (1), ultrasonically vibrate, clean and then blow dry; The polishing mesh size is 2400~3000 mesh, the ultrasonic oscillation time is 8~10 min, and the cleaning time is 5~7 min.

3. The wide-temperature-range lubricating TiAlVAgN composite coating according to claim 1, characterized in that, The vacuum degree in step (1) is 1×10 -3 ~3×10 -3 Pa, furnace cavity temperature is 360~400 ℃; The inert gas flow rate is 160~200 sccm; The current for Ti, AlTi, TiAlV, and TiAlAg targets is 120~140A, and the cleaning time is 5~8 min.

4. The wide-temperature-range lubricating TiAlVAgN composite coating according to claim 1, characterized in that, The vacuum degree in steps (2) to (5) is 1×10⁻⁶. -1 ~3×10 -1 Pa, the furnace cavity temperature is 360~400 ℃.

5. The wide-temperature-range lubricating TiAlVAgN composite coating according to claim 1, characterized in that, The vacuum degree in step (6) is 1×10 -4 ~3×10 -4 Pa, furnace cavity temperature is 400~450 ℃; The heat preservation time is 120~150 min.

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