A Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of TA15 titanium alloy and its preparation method

Abstract

A Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating for TA15 titanium alloy surface and its preparation method are disclosed. A Ti-Zr-C / Ti-Zr wear-resistant modified layer is prepared on the TA15 alloy surface using a double-layer glow discharge plasma metallurgy technique. The coating mainly consists of an outer Ti-Zr-C deposition layer and an inner Ti-Zr transition layer. The transition layer is a gradient structure layer, with the Zr content continuously decreasing from the surface to the interior, and the Ti content continuously increasing from the surface to the interior. Under an action of 5.3 N, it exhibits a stable and lower coefficient of friction. Observation of its wear track morphology shows that it mainly exhibits slight abrasive wear and slight adhesive wear. Simultaneously, the preparation of the transition layer and high-temperature diffusion result in a strong metallurgical bond between the coating and the substrate, exhibiting excellent bonding strength and the ability to withstand greater external forces, effectively extending the service life of the TA15 alloy substrate and showing good application prospects.

Description

Technical Field

[0001] This invention belongs to the field of TA15 titanium alloy surface treatment, specifically relating to a Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of TA15 titanium alloy and its preparation method. Background Technology

[0002] With the continuous advancement of human aviation, the requirements for aircraft are becoming increasingly stringent. The general development trend of aerospace structural materials is towards lightweight, high strength, high modulus, high temperature resistance, and low cost. TA15 titanium alloy, with its excellent properties such as low density, high strength, high temperature resistance, and corrosion resistance, has become an important aerospace material. However, compared to some other metallic materials, TA15 titanium alloy has lower hardness, a higher coefficient of friction, and is highly sensitive to severe wear behaviors such as adhesive wear and abrasive wear, often resulting in surface damage failure during service. Therefore, improving the surface wear resistance of titanium alloys has become a current research hotspot to reduce economic losses caused by material failure. Surface engineering technology can form a protective layer on the material surface without altering its internal properties, thereby significantly extending the material's service life and offering advantages such as good economic benefits and resource conservation.

[0003] ZrC, due to its excellent properties such as moderate hardness, high Young's modulus, relatively low density, and high melting point of its oxide products, possesses outstanding physical and chemical properties that allow it to be applied under various extreme conditions. However, the strong covalent bonding, low self-diffusion coefficient, and low fracture toughness of ZrC ceramics limit their industrial applications. The introduction of Ti into ZrC, given the very similar atomic radii of Ti and Zr, which allow for infinite miscibility, and the stability of its oxide product TiO2, may offer new physical properties. Therefore, TiZrC thin films formed through co-sputtering of Ti, Zr, and C targets are likely to improve tribological properties while maintaining high hardness.

[0004] Currently, the main technologies for preparing Ti-Zr-C thin films on TA15 titanium alloy substrates are magnetron sputtering, arc ion plating, and plasma spraying, aiming to improve their wear resistance and high-temperature oxidation resistance. However, the existing technologies have the following key problems: (1) Poor interfacial bonding: Due to the difference in thermal expansion coefficients between TA15 and Ti-Zr-C, the magnetron sputtered film is prone to residual stress leading to cracking; the micron-level droplet defects of arc ion plating further weaken the interfacial performance. (2) Difficulty in composition control: The difference in sputtering yield and sputtering amount of Ti, Zr, and C leads to compositional deviation, and carbon in CVD is prone to agglomerate into the graphite phase, resulting in a decrease in hardness. (3) Insufficient high-temperature adaptability: TA15 undergoes a phase transition at >500℃, causing the film to peel off, and the plasma-sprayed film has insufficient high-temperature life due to its high porosity. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating for TA15 titanium alloy and its preparation method. By constructing a Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating with gradient characteristics on the surface of TA15 alloy, not only are the original problems of insufficient hardness and poor wear resistance of TA15 alloy overcome, but the bonding strength between the coating and the substrate is also effectively enhanced, ensuring that the coating is not easily detached under high-load service environment. This significantly improves the protective performance of the coating on the substrate and extends its overall service life.

[0006] To address the problems of the existing technology, the present invention adopts the following technical solution:

[0007] A method for preparing a Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of TA15 titanium alloy includes the following steps:

[0008] Step 1, Pretreatment of matrix material

[0009] Prepare TA15 titanium alloy and polish it step by step on metallographic sandpaper in the order of 180# to 1500#. Then polish it to a scratch-free mirror surface. After ultrasonic cleaning in alcohol for 15 minutes, blow dry it with a hair dryer for later use.

[0010] Step 2, Cleaning and Placing the Workpiece

[0011] The interior of the double-glow furnace, the insulation cover, and the target material were polished with fine sandpaper and then cleaned with alcohol. The distance between the lower surface of the Ti and Zr target material and the upper surface of the TA15 alloy was adjusted to 12 mm. During the preparation process, the TA15 alloy was used as the cathode and the Ti and Zr target material was used as the source.

[0012] Step 3, Vacuuming

[0013] Turn on the mechanical pump to evacuate the gas pressure inside the double glow furnace to below 0.1 Pa, and then introduce argon gas for 10 minutes to purge the gas and remove impurities in the furnace, so as to avoid contamination of the coating sample by impurity gases during the preparation process; as the working gas, argon gas will be kept in the air supply state during the preparation process and maintained at 35 sccm;

[0014] Step 4, Ignite

[0015] Start the bias power supply cabinet, gradually adjust the workpiece voltage to 600V and maintain this voltage for 30 minutes, bombard the workpiece surface with argon ions to remove impurities on the workpiece surface, and at the same time provide the workpiece surface with high temperature and defect concentration to create conditions for diffusion; gradually increase the target voltage to 900V and maintain this voltage for 30 minutes, bombard the target surface with argon ions.

[0016] Step 5: Prepare Ti-Zr transition coating using double-layer glow discharge plasma metallurgy.

[0017] The furnace pressure was controlled at 35 Pa, the source voltage was set to 650 V, the workpiece voltage was set to 400 V, and the Ti-Zr transition coating was prepared under pure argon conditions for 3 h, thus obtaining the Ti-Zr transition layer.

[0018] Step 6, turn off the device

[0019] Step 7, Ti-Zr-C deposition layer in wear-resistant Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating

[0020] Repeat steps 1-6, except that the substrate surface does not need to be polished in step 1 pretreatment, and a C target is added to the original Ti and Zr targets in step 2, while other operations and parameters remain unchanged.

[0021] As an improvement, in step 6, the workpiece voltage and the source voltage are reduced to 300V and 400V respectively at a rate of 50V decrease every 7 minutes and 50V decrease every 7 minutes. After holding at this temperature for 30 minutes, the equipment is turned off.

[0022] The Ti-Zr-C / Ti-Zr co-diffusion coating prepared by the above preparation method includes, from the inside out, a Ti and Zr diffusion layer, a Ti-Zr transition layer, and a Ti-Zr-C deposition layer; the transition layer is a gradient structure layer, in which the Zr element content continuously decreases from the surface to the inside, and the Ti element content continuously increases from the surface to the inside.

[0023] As an improvement, the thickness of the transition layer is 6 μm and the thickness of the deposition layer is 6.27 μm.

[0024] As an improvement, under the action of 5.3N, the Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of TA15 titanium alloy exhibits a stable and lower coefficient of friction, specifically 0.21.

[0025] Beneficial effects:

[0026] Compared with existing technologies, this invention provides a Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating for TA15 alloy surfaces and its preparation method. Through double-layer glow discharge plasma metallurgy, a Ti-Zr-C modified layer is prepared on the TA15 alloy surface, achieving metallurgical bonding between the modified layer and the substrate. A continuous gradient change in composition is achieved from the substrate to the modified layer, resulting in excellent bonding performance. Under frictional conditions, it effectively protects the substrate material and reduces the material's coefficient of friction to 0.21. The preparation of the Ti-Zr transition layer also reduces thermal mismatch between the substrate and the Ti-Zr-C modified layer, further increasing the material's wear resistance and service life. Compared with traditional binary carbide coatings, the addition of a second transition element in the ternary carbide layer creates solid solution strengthening, improving the carbide's hardness and other mechanical properties, thus enhancing its wear resistance. Attached Figure Description

[0027] Figure 1 The diagram shows the interface of the coatings prepared under different processes, where (a) is the Zr-C coating prepared in Comparative Example 1, (b) is the Ti-Zr-C coating prepared in Comparative Example 2, and (c) is the Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating prepared in Example 1.

[0028] Figure 2 The diagram shows the friction coefficient curves of the prepared coatings, including the Zr-C coating prepared in Comparative Example 1, the Ti-Zr-C coating prepared in Comparative Example 2, and the Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating prepared in Example 1.

[0029] Figure 3 A comparative schematic diagram showing the wear track morphology of Comparative Example 1, Comparative Example 2 and Example 1 under a load of 5.3 N: (a) Comparative Example 1; (b) Comparative Example 2; (c) Example 1;

[0030] Figure 4 A schematic cross-sectional view of the Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating;

[0031] Figure 5 The diagram shows the bonding force curves of Comparative Example 1, Comparative Example 2, and Example 1.

[0032] Figure 6 The graphs show the hardness and elastic modulus of Comparative Example 1, Comparative Example 2, and Example 1. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments:

[0034] Example 1

[0035] A Ti-Zr-C / Ti-Zr wear-resistant co-infiltration coating for the surface of TA15 alloy comprises a Ti-Zr-C / Ti-Zr wear-resistant co-infiltration coating deposited on the surface of TA15 alloy using a dual-glow plasma metallurgy technique, comprising a 6μm transition layer and a 6.27μm deposition layer from the inside out; in the transition layer, the Zr content continuously decreases with depth, while the Ti content continuously increases with depth.

[0036] A method for preparing a Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of a TA15 alloy includes the following steps:

[0037] Step 1, Pretreatment of matrix material:

[0038] Prepare TA15 alloy and polish it step by step on metallographic sandpaper in the order of 180# to 1000#. Then polish it to a scratch-free mirror finish, ultrasonically clean it in alcohol, and let it air dry for later use.

[0039] Step 2, Cleaning and Placing the Workpiece:

[0040] The interior of the dual-glow furnace, the insulation cover, and the target material were polished using fine sandpaper, and then cleaned with alcohol. The distance between the lower surface of the Ti / Zr target and the upper surface of the TA15 alloy was adjusted to 12 mm. In the fabrication process, the TA15 alloy was used as the cathode, and the Ti / Zr target was used as the source; both targets were gate targets.

[0041] Step 3, Vacuuming:

[0042] Turn on the mechanical pump to evacuate the gas pressure inside the double glow furnace to below 0.1 Pa. Then, argon gas is introduced for ten minutes to purge the gas and remove impurities from the furnace, preventing contamination of the coated sample by impurity gases during the preparation process. Argon gas will be continuously introduced as the working gas during the preparation process.

[0043] Step 4, Ignition:

[0044] Start the bias power supply cabinet, gradually adjust the workpiece voltage to 600V and hold it at that temperature for 30 minutes, then bombard the workpiece surface with argon ions to remove impurities and provide high temperature and defect concentration to the workpiece surface to create conditions for diffusion; gradually increase the target voltage to 900V and hold it at that voltage for 30 minutes, then bombard the target surface with argon ions.

[0045] Step 5: Preparation of Ti-Zr-C wear-resistant co-diffusion coating using double-layer glow discharge plasma metallurgy:

[0046] The furnace pressure was controlled at 35 Pa, the source voltage was set to 650 V, and the workpiece voltage was set to 400 V. The Ti-Zr transition layer was prepared under pure argon conditions for 3 hours, thus obtaining the Ti-Zr transition layer.

[0047] Step 6, turn off the device:

[0048] After the heat preservation is completed, slowly reduce the workpiece voltage and the source voltage to 300V and 400V respectively, and then turn off the equipment after heat preservation for 30 minutes.

[0049] Step 7, Preparation of Ti-Zr-C deposition layer in wear-resistant Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating:

[0050] Repeat steps 1-6. Except for step 1, where no grinding is required on the substrate surface, and step 2, where a C target is added to the existing Ti and Zr targets, all other operations and parameters remain unchanged. Repeat steps 1-6.

[0051] The coating structure prepared in Example 1 of this invention is as follows: Figure 4 As shown, the thickness of the Ti-Zr-C deposition layer is 6.27 μm, and the thickness of the Ti-Zr transition layer is 6 μm.

[0052] Comparative Example 1

[0053] The coating preparation steps are different from those shown in Example 1, except that:

[0054] Step 5: Preparation of Zr-C wear-resistant coating using double-layer glow discharge plasma metallurgy:

[0055] The distance between the lower surface of the Zr and C target and the upper surface of the TA15 alloy is 12 mm. The gas pressure inside the furnace is controlled at 35 Pa, the source voltage is set to 850 V, the workpiece voltage is set to 350 V, and Zr and C diffusion is carried out for 6 hours under pure argon conditions to prepare the Zr-C wear-resistant coating.

[0056] It should be noted that Comparative Example 1 only proceeds up to step 6.

[0057] Comparative Example 2

[0058] The coating preparation steps are different from those shown in Example 1, except that:

[0059] Step 5: Preparation of Ti-Zr-C wear-resistant coating using double-layer glow discharge plasma metallurgy:

[0060] The distance between the lower surface of the Ti, Zr, and C target and the upper surface of the TA15 alloy is 12 mm. The gas pressure inside the furnace is controlled at 30 Pa, the source voltage is set to 750 V, and the workpiece voltage is set to 350 V. Ti, Zr, and C diffusion is carried out for 6 hours under pure argon conditions to prepare the Ti-Zr-C wear-resistant coating.

[0061] It should be noted that Comparative Example 2 only proceeds up to step 6.

[0062] Friction and wear experiments were conducted on the materials prepared in Example 1 and Comparative Examples 1-2. A ball-and-disc tribometer was used to study the wear behavior of the Ti-Zr-C / Ti-Zr wear-resistant co-infiltration coating under real-world conditions. The specific procedures were as follows: the sample was placed on a platform and fixed with a clamp; a 5mm diameter Si3N4 friction pair was used; the temperature was 25℃; the rotational speed was 560 r / min; the load was 5.3 N; the friction radius was 2mm; and the wear time was 15 min. After the experiment, the friction coefficient was recorded and the wear track morphology was observed.

[0063] Adhesion strength tests were conducted on Comparative Examples 1-2 and Example 1, using a Rockwell diamond indenter with a cone angle of 120° and a tip radius of 0.2 mm. The maximum load in this experiment was 80 N, the loading rate was 80 N / min, and a 5 mm scratch length was achieved at a sliding speed of 5 mm / min. Figure 2 As shown in the figure, the friction coefficient curves indicate that the friction coefficient of ZrC is approximately 0.3, with a stable curve; the friction coefficient of the Ti-Zr-C coating is approximately 0.37, with a larger fluctuation in the curve; and the friction coefficient of the Ti-Zr-C / Ti-Zr coating is approximately 0.21, with a stable curve.

[0064] like Figure 3 As shown, under a load of 5.3 N, Comparative Example 1 mainly exhibits abrasive wear and slight adhesive wear, while Comparative Example 2 mainly exhibits adhesive wear and slight abrasive wear. However, Example 1, due to the addition of a transition layer and solid solution strengthening leading to increased hardness, shows wear track morphology mainly exhibiting slight adhesive wear and slight abrasive wear. Figure 5 As shown, (a) indicates that the bonding strength of Comparative Example 1 is 32.2 N; (b) indicates that the bonding strength of Comparative Example 2 is 61 N; and (c) indicates that the bonding strength of Example 1 is 36 N. All coatings exhibit good bonding performance. Figure 6 As shown, the hardness of Comparative Example 1 is 16 GPa and the elastic modulus is 214.84 GPa; the hardness of Comparative Example 2 is 17.35 GPa and the elastic modulus is 186.78 GPa; and the hardness of Example 1 is 28.17 GPa and the elastic modulus is 251.87 GPa.

[0065] In summary, the Ti-Zr-C / Ti-Zr modified layer of this invention achieves diffusion bonding through the introduction of the transition layer Ti-Zr and the double-layer glow discharge plasma metallurgy technology, enabling the coating to form a metallurgical bond with the TA15 alloy. The composition changes continuously from the outside to the inside of the modified layer surface, resulting in good bonding performance. Under frictional conditions, it can effectively protect the base material and reduce the friction coefficient of the material to 0.21.

[0066] The above description is merely a preferred embodiment of the present invention and does not constitute a limitation on the scope of application of the present invention. For those skilled in the art, the present invention has many possible modifications and variations. Any adjustments, equivalent substitutions, optimizations, or improvements made within the core concept and basic principles framework of the present invention should be considered to fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of TA15 titanium alloy, characterized in that, Includes the following steps: Step 1, Pretreatment of matrix material Prepare TA15 titanium alloy and polish it step by step on metallographic sandpaper in the order of 180# to 1500#. Then polish it to a scratch-free mirror surface. After ultrasonic cleaning in alcohol for 15 minutes, blow dry it with a hair dryer for later use. Step 2, Cleaning and Placing the Workpiece Use fine sandpaper to polish the inside of the double-burn furnace body, as well as the insulation cover and the target material. After polishing, clean with alcohol. The distance between the lower surface of the Ti and Zr targets and the upper surface of the TA15 alloy was adjusted to 12 mm; during the preparation process, the TA15 alloy was used as the cathode and the Ti and Zr targets were used as the source. Step 3, Vacuuming Turn on the mechanical pump to evacuate the gas pressure inside the double glow furnace to below 0.1 Pa, and then introduce argon gas for 10 minutes to purge the gas and remove impurities in the furnace, so as to avoid contamination of the coating sample by impurity gases during the preparation process; as the working gas, argon gas will be kept in the air supply state during the preparation process and maintained at 35 sccm; Step 4, Ignite Start the bias power supply cabinet, gradually adjust the workpiece voltage to 600V and maintain this voltage for 30 minutes, bombard the workpiece surface with argon ions to remove impurities on the workpiece surface, and at the same time provide the workpiece surface with high temperature and defect concentration to create conditions for diffusion; gradually increase the target voltage to 900V and maintain this voltage for 30 minutes, bombard the target surface with argon ions. Step 5: Prepare Ti-Zr transition coating using double-layer glow discharge plasma metallurgy. The furnace pressure was controlled at 35 Pa, the source voltage was set to 650 V, the workpiece voltage was set to 400 V, and the Ti-Zr transition coating was prepared under pure argon conditions for 3 h, thus obtaining the Ti-Zr transition coating. Step 6, turn off the device The workpiece voltage and source voltage are reduced to 300V and 400V respectively at a rate of 50V decrease every 7 minutes and 50V decrease every 7 minutes. The equipment is then shut down after holding the temperature for 30 minutes. Step 7: Prepare the Ti-Zr-C deposition layer in the Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating. Repeat steps 1-6, except that the substrate surface does not need to be polished in step 1 pretreatment, and a C target is added to the original Ti and Zr targets in step 2, while other operations and parameters remain unchanged.

2. The Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of TA15 titanium alloy prepared by the preparation method described in claim 1, characterized in that, It includes a Ti-Zr diffusion layer, a Ti-Zr transition layer, and a Ti-Zr-C deposition layer from the inside out; in the transition layer, the Zr content decreases continuously from the surface to the inside, while the Ti content increases continuously from the surface to the inside.

3. The Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of TA15 titanium alloy according to claim 2, characterized in that, The thickness of the Ti-Zr transition layer is 6 μm, and the thickness of the Ti-Zr-C deposition layer is 6.27 μm.

4. The Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of TA15 titanium alloy according to claim 2, characterized in that, Under the influence of 5.3N, the Ti-Zr-C / Ti-Zr wear-resistant co-diffusion coating on the surface of TA15 titanium alloy exhibits a stable and lower coefficient of friction, specifically 0.21.

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