Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on TA15 titanium alloy surface and preparation method thereof

Abstract

The invention discloses a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy and a preparation method thereof. A Ti-Zr-C / Ti-Zr wear-resistant modified layer is prepared on the surface of the TA15 alloy through the double glow plasma metallurgy technology, the coating is mainly composed of a Ti-Zr-C deposition layer on the outer layer and a Ti-Zr transition layer on the inner layer, the transition layer is a gradient structure layer, the content of the Zr element is continuously decreased from the surface to the inside, and the content of the Ti element is continuously increased from the surface to the inside. Under the action of 5.3 N, the lubricating oil shows a stable and lower friction coefficient, and by observing the shape of a grinding crack, the lubricating oil mainly shows slight abrasive wear and slight adhesive wear. Meanwhile, firm metallurgical bonding is formed between the coating and the base body through preparation and high-temperature diffusion of the transition layer, excellent bonding strength is shown, large external force can be borne, the service life of the TA15 alloy base body is effectively prolonged, and good application prospects are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of surface treatment of TA15 titanium alloy, and particularly relates to a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy and a preparation method thereof. Background Art

[0002] With the continuous progress of the human aviation industry, the requirements for aircraft are getting higher and higher. The general development trend of aviation structural materials is light weight, high strength, high modulus, high temperature resistance, and low cost. TA15 titanium alloy has become an important aviation material due to its excellent properties such as low density, high strength, high temperature resistance, and corrosion resistance. However, compared with some other metal materials, TA15 titanium alloy has lower hardness, a large friction coefficient, and is very sensitive to severe wear behaviors such as adhesive wear and abrasive wear, and surface damage and failure often occur during service. Therefore, in order to reduce the economic losses caused by material failure and improve the surface wear resistance of titanium alloy has become a research hotspot at present. Surface engineering technology can form a protective layer on the material surface without changing the internal properties of the material, thereby greatly improving the service life of the material, and has the advantages of good economic benefits and resource savings.

[0003] Due to its excellent properties, such as medium hardness, high Young's modulus, relatively low density, and high melting point of oxidation products, the excellent physical and chemical properties of ZrC enable it to be applied to various extreme conditions. However, due to the strong covalent bond binding force, low self-diffusion coefficient, and low fracture toughness of ZrC ceramics, the industrial application of ZrC ceramics is limited. When Ti is introduced into ZrC, due to the very close atomic radii of Ti and Zr, they can be infinitely miscible, and its oxidation product TiO2 is stable, which may provide new physical properties. Therefore, TiZrC thin films formed by co-sputtering of Ti, Zr, and C targets will likely improve the tribological properties while maintaining high hardness.

[0004] Currently, the technologies for preparing Ti-Zr-C thin films on TA15 titanium alloy substrates mainly adopt processes such as magnetron sputtering, arc ion plating, and plasma spraying, aiming to improve its wear resistance and high-temperature oxidation resistance. However, the existing technologies have the following key problems: (1) Poor interfacial bonding force: Due to the difference in thermal expansion coefficients between TA15 and Ti-Zr-C, residual stress is easily generated in the magnetron sputtered film layer, resulting in cracking; the micron-sized droplet defects in arc ion plating further weaken the interfacial properties. (2) Difficult composition control: The differences in sputtering yields and sputtering yields of Ti, Zr, and C lead to composition deviation, and carbon is easily segregated into graphite phase in CVD, resulting in a decrease in hardness. (3) Insufficient high-temperature adaptability: TA15 undergoes a phase change at >500 °C, causing film layer spalling, and the plasma sprayed film layer has insufficient high-temperature life due to high porosity. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention proposes a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy and its preparation method. By constructing a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating with gradient characteristics on the surface of TA15 alloy, not only the problems of insufficient original hardness and poor wear resistance of TA15 alloy are overcome, but also the bonding strength between the coating and the substrate is effectively enhanced, ensuring that the coating is not easy to fall off under high-load service environments, thereby significantly improving the protection efficiency of the coating for the substrate and extending its overall service life.

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

[0007] A preparation method of a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy, comprising the following steps:

[0008] Step 1, pretreatment of the substrate material

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

[0010] Step 2, cleaning and placing the workpiece

[0011] Use fine sandpaper to polish the inside of the double glow furnace body, the heat preservation cover, and the target. After polishing, clean it with alcohol; adjust the distance between the lower surface of the Ti and Zr targets and the upper surface of the TA15 alloy to 12 mm; during the preparation process, the TA15 alloy serves as the cathode, and the Ti and Zr targets serve as the source electrodes;

[0012] Step 3, evacuation

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

[0014] Step 4, starting glow

[0015] Start the bias power supply cabinet, gradually adjust the workpiece voltage to 600 V and keep this voltage for 30 minutes to perform argon ion bombardment on the workpiece surface to remove impurities on the workpiece surface, and at the same time provide high temperature and defect concentration for the workpiece surface to create conditions for diffusion; gradually raise the target voltage to 900 V and keep this voltage for 30 minutes to perform argon ion bombardment on the target surface;

[0016] Step 5, preparing a Ti-Zr transition coating by double glow plasma metallurgy technology

[0017] The furnace internal pressure is controlled at 35 Pa, the source electrode voltage is set at 650 V, the workpiece voltage is set at 400 V, and the Ti-Zr transition coating is prepared for 3 h under pure argon conditions to obtain a Ti-Zr transition layer;

[0018] Step 6, turn off the equipment

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

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

[0021] As an improvement, in step 6, the workpiece voltage and the source electrode voltage are respectively reduced to 300 V and 400 V at a rate of the workpiece voltage decreasing by 50 V every 7 min and the source electrode voltage decreasing by 50 V every 7 min, and the equipment is turned off after heat preservation for 30 minutes.

[0022] The Ti-Zr-C / Ti-Zr co-permeation coating prepared by the above preparation method includes a Ti, Zr diffusion layer, a Ti-Zr transition layer and a Ti-Zr-C deposition layer from the inside to the outside; the transition layer is a gradient structure layer, 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 5.3 N, the Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy shows a stable and lower friction coefficient, specifically 0.21.

[0025] Beneficial effects:

[0026] Compared with the prior art, a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 alloy and a preparation method thereof realize metallurgical bonding between the modified layer and the matrix through double glow plasma metallurgy technology, achieve continuous gradient change of composition from the matrix to the modified layer, have good bonding performance, can effectively protect the matrix material in a friction environment, and reduce the friction coefficient of the material to 0.21. The preparation of the transition layer Ti-Zr also reduces the thermal mismatch problem between the matrix and the Ti-Zr-C modified layer, further increasing the wear resistance and service life of the material. Compared with the traditional binary carbide coating, the addition of the second transition metal element in the ternary carbide forms solid solution strengthening and other effects, improving the mechanical properties such as the hardness of the carbide and enhancing its wear resistance. Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the interface of the coatings prepared under different processes. Among them, (a) is the Zr-C coating prepared in Comparative Example 1, (b) is the Ti-Zr-C coating prepared in Comparative Example 2; (c) is the Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating prepared in Example 1;

[0028] Figure 2 It is a schematic diagram of the friction coefficient curve of the prepared coatings. Among them, 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-permeation coating prepared in Example 1;

[0029] Figure 3 It is a schematic diagram of the comparison of the wear scar morphologies 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 It is a schematic cross-sectional view of the Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating;

[0031] Figure 5 It is a bonding force curve graph of Comparative Example 1, Comparative Example 2 and Example 1;

[0032] Figure 6 It is a hardness and elastic modulus graph of Comparative Example 1, Comparative Example 2 and Example 1. Detailed Embodiments

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

[0034] Example 1

[0035] A Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 alloy, including a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating obtained by double glow plasma metallurgy technology and deposited on the surface of TA15 alloy, including a 6μm transition layer and a 6.27μm deposition layer from the inside to the outside; the content of Zr element in the transition layer decreases continuously with the depth, while the content of Ti element increases continuously with the depth.

[0036] A preparation method of a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 alloy, comprising the following steps:

[0037] Step 1, pretreatment of the substrate material:

[0038] Prepare TA15 alloy, polish it step by step on metallographic sandpaper in the order of 180# to 1000#, and then polish it to a mirror surface without scratches. After ultrasonic cleaning in alcohol, dry it for standby;

[0039] Step 2, cleaning and placing the workpiece:

[0040] Use fine sandpaper to polish the inside of the double glow furnace body, the heat preservation cover and the target. After polishing, clean it with alcohol. Adjust the distance between the lower surface of the Ti and Zr targets and the upper surface of the TA15 alloy to 12mm. During the preparation process, the TA15 alloy is used as the cathode, and the Ti and Zr targets are used as the source electrodes. The targets are all grid targets.

[0041] Step 3, vacuum pumping:

[0042] Turn on the mechanical pump, pump the air pressure in the double glow furnace to below 0.1Pa, and then introduce argon for ten minutes for gas cleaning to remove gas impurities in the furnace and avoid the pollution of the coating sample by impurity gases during the preparation process. As the working gas, argon will be kept introduced during the preparation process.

[0043] Step 4, starting glow:

[0044] Start the bias power supply cabinet, gradually adjust the workpiece voltage to 600V and keep it warm for 30 minutes to bombard the workpiece surface with argon ions to remove impurities on the workpiece surface, and at the same time provide high temperature and defect concentration for the workpiece surface to create conditions for diffusion; gradually raise the target voltage to 900V and keep this voltage for 30 minutes to bombard the target surface with argon ions.

[0045] Step 5, preparing the Ti-Zr-C wear-resistant co-permeation coating by double glow plasma metallurgy technology:

[0046] Control the air pressure in the furnace at 35Pa, set the source electrode voltage at 650V, and set the workpiece voltage at 400V. Prepare the Ti-Zr transition layer for 3h under pure argon conditions to obtain the Ti-Zr transition layer.

[0047] Step 6, shutting down the equipment:

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

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

[0050] Repeat Steps 1-6. Except that in Step 1 pretreatment, the surface of the substrate does not need to be polished, and in Step 2, a C target is added on the basis of the original Ti and Zr targets, other operations and parameters remain unchanged, and repeat Steps 1-6.

[0051] The coating structure prepared in Example 1 of the present invention is as Figure 4 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 difference in the coating preparation steps from those shown in Example 1 lies in:

[0054] Step 5, preparation of the Zr-C wear-resistant coating by double glow plasma metallurgy technology:

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

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

[0057] Comparative Example 2

[0058] The difference in the coating preparation steps from those shown in Example 1 lies in:

[0059] Step 5, preparation of the Ti-Zr-C wear-resistant coating by double glow plasma metallurgy technology:

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

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

[0062] Friction and wear experiments were carried out on the materials prepared in Example 1 and Comparative Examples 1-2. A ball-on-disk friction and wear tester was used to study the wear behavior of the Ti-Zr-C / Ti-Zr wear-resistant co-deposited coating in a real environment. The specific operations are as follows: The specimen was placed on a platform and fixed with a fixture. The friction pair was Si3N4 with a diameter of 5 mm, the temperature was 25 °C, the rotation speed was 560 r / min, the load was 5.3 N, the friction radius was 2 mm, and the wear time was 15 min. After the experiment, the friction coefficient was recorded and the wear scar morphology was observed.

[0063] Adhesion tests were carried out on Comparative Examples 1-2 and Example 1. The indenter was 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 scratch length of 5 mm was completed at a sliding speed of 5 mm / min. As Figure 2 shown, according to the friction coefficient curve, the friction coefficient of ZrC is about 0.3 and the curve is stable. The friction coefficient of the Ti-Zr-C coating is about 0.37 and the curve fluctuates greatly. The friction coefficient of the Ti-Zr-C / Ti-Zr coating is about 0.21 and the curve is stable.

[0064] As Figure 3 shown, under a load of 5.3 N, abrasive wear and slight adhesive wear were mainly exhibited in Comparative Example 1, and adhesive wear and slight abrasive wear were mainly exhibited in Comparative Example 2. In Example 1, due to the addition of the transition layer and solution strengthening, its hardness increased, and the wear scar morphology mainly showed slight adhesive wear and slight abrasive wear. As Figure 5 shown, (a) shows that the adhesion of Comparative Example 1 is 32.2 N; (b) shows that the adhesion of Comparative Example 2 is 61 N; (c) shows that the adhesion of Example 1 is 36 N, and the coatings all exhibit good adhesion performance. As Figure 6 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; the hardness of Example 1 is 28.17 GPa and the elastic modulus is 251.87 GPa.

[0065] In summary, due to the introduction of the transition layer Ti-Zr and the double glow plasma metallurgy technology, the Ti-Zr-C / Ti-Zr modified layer of the present invention realizes the combination of infiltration and plating, enables the coating to form a metallurgical bond with the TA15 alloy, the composition changes continuously in a gradient from the surface to the inside of the modified layer, has good bonding performance, and can effectively protect the substrate material in a friction environment and reduce the friction coefficient of the material to 0.21.

[0066] The above content is only the preferred implementation 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, there are various possible modifications and changes to the present invention. Any adjustments, equivalent substitutions, optimizations, etc. made within the framework of the core concept and basic principles of the present invention should be regarded as falling within the scope of protection of the claims of the present invention.

Claims

1. A preparation method of a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy, characterized in that, It includes the following steps: Step 1, pretreatment of the substrate material Prepare TA15 titanium alloy, grind it step by step on metallographic sandpaper in the order of 180# to 1500#, then polish it to a scratch-free mirror surface, ultrasonically clean it in alcohol for 15 min, and dry it with a hair dryer for standby; Step 2, cleaning and placing the workpiece Use fine sandpaper to grind the inside of the double glow furnace body, the thermal insulation cover and the target, and clean it with alcohol after grinding; Adjust the distance between the lower surface of the Ti and Zr targets and the upper surface of the TA15 alloy to 12 mm; during the preparation process, the TA15 alloy is used as the cathode, and the Ti and Zr targets are used as the source electrodes; Step 3, evacuating the vacuum Turn on the mechanical pump, evacuate the air pressure in the double glow furnace to below 0.1 Pa, then introduce argon for 10 minutes for gas cleaning to remove gas impurities in the furnace and avoid contamination of the coating sample by impurity gases during the preparation process; as the working gas, argon will be kept introduced during the preparation process and maintained at 35 sccm; Step 4, starting to glow Start the bias power supply cabinet, gradually adjust the workpiece voltage to 600 V and keep this voltage for 30 minutes to bombard the workpiece surface with argon ions to remove impurities on the workpiece surface, and at the same time provide high temperature and defect concentration on the workpiece surface to create conditions for diffusion; gradually raise the target voltage to 900 V and keep this voltage for 30 minutes to bombard the target surface with argon ions; Step 5, preparing the Ti-Zr transition coating by double glow plasma metallurgy technology Control the furnace pressure at 35 Pa, set the source electrode voltage at 650 V, and set the workpiece voltage at 400 V. Prepare the Ti-Zr transition coating for 3 h under pure argon conditions to obtain the Ti-Zr transition layer; Step 6, shutting down the equipment Step 7, Ti-Zr-C deposition layer in the wear-resistant Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating Repeat steps 1-6, where in step 1 pretreatment, there is no need to grind the substrate surface, and in step 2, a C target is added on the basis of the original Ti and Zr targets, and other operations and parameters remain unchanged.

2. The preparation method of a Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy according to claim 1, characterized in that, In step 6, reduce the workpiece voltage and the source electrode voltage to 300 V and 400 V respectively at a rate of reducing the workpiece voltage by 50 V every 7 min and reducing the source electrode voltage by 50 V every 7 min, keep warm for 30 minutes, and then shut down the equipment.

3. The Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy prepared by the preparation method according to 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 to the outside; the transition layer is a gradient structure layer, 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.

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

5. The Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of TA15 titanium alloy according to claim 3, wherein, Under the action of 5.3 N, the Ti-Zr-C / Ti-Zr wear-resistant co-permeation coating on the surface of the TA15 titanium alloy shows a stable and lower friction coefficient, specifically 0.21.

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