A wear-resistant and oxidation-resistant quaternary nitride coating on titanium alloy surface and its preparation method and application

Abstract

The present invention discloses a wear-resistant and oxidation-resistant quaternary nitride coating on the surface of titanium alloy, and its preparation method and application. The present invention adopts an improved dual-cathode plasma surface metallurgy technology to prepare a wear-resistant and oxidation-resistant quaternary nitride ceramic coating, and realizes rapid preparation of the coating by improving the target material structure, controlling the sputtering gas pressure, current, temperature and other factors. The coating prepared by the present invention has uniform composition, is composed of nanocrystals with a single face-centered cubic structure, is well bonded to the substrate, and has no obvious defects. The coating of the present invention has good wear resistance below 500°C and good oxidation resistance below 800°C, can effectively slow down the wear loss and oxidation failure of titanium alloys in high temperature environments, and has extremely high application potential in the field of thermal environment machinery.

Description

Technical Field

[0001] The present invention belongs to the field of transition nitride coatings, and in particular relates to a wear-resistant and oxidation-resistant quaternary nitride coating on the surface of a titanium alloy, and a preparation method and application thereof. Background Art

[0002] Titanium alloys, as important materials in fields such as aerospace, transportation, petrochemicals, and biomedicine, have advantages such as low density, high specific strength, strong corrosion resistance, heat resistance, good plasticity and toughness, and excellent processability. They occupy an important position in cutting-edge disciplines and high-tech fields. However, due to their low inherent surface hardness, titanium alloys have a large friction coefficient in friction environments, are prone to adhesive wear, have poor wear resistance, and are severely oxidized and difficult to lubricate under high temperature conditions. These characteristics greatly limit the usability and application range of titanium alloys. In particular, the use of titanium alloys in friction pair moving parts is severely restricted. Therefore, improving the wear resistance of titanium alloy surfaces and their oxidation resistance in high temperature environments is of great significance to expanding the application range of titanium alloys.

[0003] At the same time, for aircraft engine components such as compressor disks, blades, and casings, whose operating temperatures often exceed 600°C, oxidation will have a significant detrimental effect on the performance of titanium alloys. Improving the alloy's oxidation resistance solely through overall alloy composition design and microstructure control has limited effect. Therefore, adopting effective surface protection methods to improve the high-temperature oxidation resistance of titanium alloys is an important way to solve this problem.

[0004] Common methods for preparing high-temperature protective coatings on titanium alloy surfaces include thermal diffusion, physical vapor deposition, melt sintering, laser cladding, ion implantation, and electrospark deposition. Key high-temperature protective coatings include thermal diffusion aluminum (silicon) coatings, intermetallic compound coatings, Ti-Al-X metal coatings, binary nitride coatings, and oxide coatings. However, these coatings are limited by the preparation process, coating elements, and bonding strength, often failing to guarantee both good wear resistance and oxidation resistance at room or high temperatures. In recent years, researchers have devoted significant effort to developing integrated oxidation- and wear-resistant coating materials, employing crystallographic designs of nanocrystalline and amorphous materials, structural designs employing multilayer, micro-laminated, and gradient structures, and multi-component alloying. However, currently, no clear coating design and preparation method exists that can simultaneously enhance the wear resistance and oxidation resistance of titanium alloys at medium and high temperatures.

[0005] Therefore, there is an urgent need for a coating design and preparation method that can improve the comprehensive performance of the coating and has an efficient and environmentally friendly preparation process. Summary of the Invention

[0006] In response to the deficiencies in the prior art, the present invention provides a wear-resistant and oxidation-resistant quaternary nitride coating on the surface of a titanium alloy and a preparation method thereof. The quaternary nitride coating is tightly bonded to the substrate, has good high-temperature wear resistance, and has good oxidation resistance. The quaternary nitride coating that is tightly bonded to the titanium alloy substrate can be quickly prepared, effectively improving the wear resistance and oxidation resistance of titanium alloy structural components at high temperatures.

[0007] In order to solve the problems of the prior art, the technical solution adopted by the present invention is:

[0008] A wear-resistant and oxidation-resistant quaternary nitride coating on a titanium alloy surface, wherein the quaternary nitride coating is prepared from four elements: Zr, Ta, Nb, and N. The dry sliding wear rate of the quaternary nitride coating at any temperature below 500°C is less than 4×10 - 5 mm 3 / N·m, and the coating can still remain intact after cyclic oxidation at a temperature below 800℃ for 100h.

[0009] The method for preparing the wear-resistant and oxidation-resistant quaternary nitride coating on the surface of the titanium alloy is prepared using a dual cathode glow plasma surface metallurgy equipment equipped with a grid-shaped target, and includes the following steps:

[0010] Step 1: Substrate surface pretreatment

[0011] The titanium alloy wire was cut into the size of 15 mm × 15 mm × 3 mm, then polished to 1200 mesh using SiC sandpaper, polished using Cr2O3 suspension, and ultrasonically cleaned in alcohol;

[0012] Step 2: Use grid target

[0013] Use single-piece targets instead of conventional round targets, and control the deposition elements by adjusting the composition and quantity of the target;

[0014] Step 3: Set reasonable tooling spacing

[0015] Adjust the target spacing and the distance between the target and the substrate to control the sputtering intensity;

[0016] Step 4: Control the gas pressure, target voltage, substrate voltage, temperature, and time during the preparation process to achieve stable preparation of the coating by controlling the parameters.

[0017] As an improvement, the grid-shaped target material in step 2 is composed of independent pure metal sheets with a purity of not less than 99.9%, and the metal sheets are all rectangular thin sheets of 60mm×20mm×3mm, and the short sides are arranged in a circular array in parallel through stainless steel brackets, wherein the pure metal sheets are pure Zr sheets, pure Ta sheets, and pure Nb sheets, and the quantity ratio is 1:1:1.

[0018] As an improvement, the tooling spacing in step 3 includes the following parameters:

[0019] In the first step, the distance between the target metal sheets is 5~15 mm;

[0020] In the second step, the distance between the plane where the bottom of the target metal sheet is located and the upper surface of the substrate is 15~20 mm.

[0021] As an improvement, in step 4, the gas pressure is 20~25 Pa, the target voltage is controlled to 800V~900V, the substrate voltage is controlled to 350V~400V, the temperature is controlled to 700℃~1000℃, and the holding time is 3~5h.

[0022] The quaternary nitride coating is applied to the surfaces of connecting parts that are prone to wear and oxidation, such as titanium alloy blades, compressor wheels, or pins made of titanium alloy for engines. Beneficial effects

[0023] Compared with the prior art, the wear-resistant and oxidation-resistant quaternary nitride coating on the surface of titanium alloy of the present invention and its preparation method and application have the following advantages:

[0024] 1. The grid-shaped target used in the present invention enables rapid design and preparation of coatings without the need for prefabricated alloy targets;

[0025] 2. The coating prepared by the present invention is tightly bonded to the substrate, achieving a metallurgical bonding effect, and the coating composition is uniform without defects such as holes and cracks.

[0026] 3. The coating prepared by the present invention can have a dry sliding wear rate of less than 4×10 at a temperature below 500°C. -5 mm 3 / N·m.

[0027] 4. The coating prepared by the present invention can still maintain its integrity after cyclic oxidation at a temperature below 800°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 1 is a schematic diagram of the assembly of the ternary grid target of Example 1, where A, B, and C represent three different metal elements;

[0029] Figure 2 This is a SEM scan of the coating cross section of the sample obtained in Example 1.

[0030] Figure 3 This is the XRD test result diagram of the coating surface obtained in Example 1.

[0031] Figure 4 This is a cross-sectional view of the wear scar after the friction and wear test in Example 1.

[0032] Figure 5 This is a cross-sectional view after the cyclic oxidation experiment in Example 1. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments of the present invention. Example 1

[0034] A ZrTaNbN quaternary nitride coating is prepared using a dual cathode glow plasma surface metallurgy device. The specific preparation method is as follows:

[0035] (1) Surface pretreatment of the substrate: The titanium alloy wire was cut into pieces with a size of 15 mm × 15 mm × 3 mm, then polished to 1200 mesh using SiC sandpaper, polished using Cr2O3 suspension, and ultrasonically cleaned in alcohol;

[0036] (2) Use a grid-shaped target material (such as Zr, Ta, Nb pure metal sheets (purity of 99.9%) with a size of 60mm×20mm×3mm) Figure 1 ) as a sputtering target, with a spacing of 15 mm between metal sheets; the distance between the bottom of the grid-shaped target and the surface of the titanium alloy substrate is set at 17 mm, wherein the number ratio of pure Zr sheets, pure Ta sheets, and pure Nb sheets is 1:1:1, and they are arranged in two cycles, for a total of 6 pure metal sheets;

[0037] (4) Close the furnace chamber, evacuate to below 0.1 Pa, and then introduce pure argon gas. When the pressure in the furnace stabilizes at 20 Pa, pre-sputtering of the substrate and target is performed respectively. The pre-sputtering voltage of the substrate is 500 V, the pre-sputtering voltage of the target is 800 V, and the sputtering time is 20 min.

[0038] (5) Coating preparation: adjust the target voltage to 800 V, the substrate voltage to 400 V, the atmosphere to a mixed gas of argon (70 sccm) + nitrogen (30 sccm), the sputtering time to 4 h, and the sputtering field temperature to 900 °C;

[0039] (6) After the sputtering is completed, the voltage between the two electrodes is turned off evenly and slowly within 30 minutes, the argon gas is turned off, the nitrogen gas is turned off, the furnace is evacuated to below 0.1 Pa, and the circulating water is cooled for 6 to 8 hours to room temperature. The furnace can then be opened for sampling.

[0040] The coating prepared by the above steps has a thickness of about 9 μm and is dense and has no holes (e.g. Figure 2 ). XRD test results show that it has obvious (220) crystal orientation (such as Figure 3 ), in the ball-on-disc friction and wear test at room temperature under a load of 330g, the coating can maintain a wear rate below 4×10 -5 mm 3 / N·m. The wear scar profile is as follows Figure 4As shown. After the coating was oxidized at 800℃ for 10h, the coating was intact without cracks or peeling (such as Figure 5 ). Example 2

[0041] A ZrTaNbN quaternary nitride coating is prepared using a dual cathode glow plasma surface metallurgy device. The specific preparation method is as follows:

[0042] (1) Surface pretreatment of the substrate: The titanium alloy wire was cut into pieces with a size of 15 mm × 15 mm × 5 mm, then polished to 1200 mesh using SiC sandpaper, polished using Cr2O3 suspension, and ultrasonically cleaned in alcohol;

[0043] (2) Use a grid-shaped target material (such as Zr, Ta, Nb pure metal sheets (purity of 99.9%) with a size of 60mm×20mm×3mm) Figure 1 ) as a sputtering target, with a spacing of 10 mm between metal sheets; the distance between the bottom of the grid-shaped target and the surface of the titanium alloy substrate is set at 20 mm, wherein pure Zr sheets, pure Ta sheets, and pure Nb sheets are arranged in a ratio of 1:1:1, and the arrangement is repeated twice, for a total of 6 pure metal sheets;

[0044] (4) Close the furnace chamber, evacuate to below 0.1 Pa, and then introduce pure argon gas. When the pressure in the furnace stabilizes at 20 Pa, pre-sputtering of the substrate and target is performed respectively. The pre-sputtering voltage of the substrate is 500 V, the pre-sputtering voltage of the target is 800 V, and the sputtering time is 20 min.

[0045] (5) Coating preparation: Adjust the target voltage to 850 V, the substrate voltage to 400 V, the atmosphere to a mixed gas of argon (75 sccm) + nitrogen (25 sccm), the sputtering time to 4 h, and the sputtering field temperature to around 950 °C.

[0046] (6) After the sputtering is completed, the voltage between the two electrodes is turned off evenly and slowly within 30 minutes, the argon gas is turned off, the nitrogen gas is turned off, the furnace is evacuated to below 0.1 Pa, and the circulating water is cooled for 6 to 8 hours to room temperature. The furnace can then be opened for sampling.

[0047] The coating prepared by the above steps is approximately 11 μm thick and dense without pores. XRD test results show that it has a clear (220) crystal orientation. In the ball-on-disk friction and wear test with a load of 330 g and a temperature below 500 ° C, the coating can maintain a wear rate below 4×10 -5 mm 3 / N·m.

[0048] The above is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the embodiments of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the embodiments of the present invention are still within the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wear-resistant and oxidation-resistant quaternary nitride coating on the surface of a titanium alloy, characterized in that: The quaternary nitride coating is prepared from four elements: Zr, Ta, Nb and N, and the dry sliding wear rate of the quaternary nitride coating at any temperature below 500°C is less than 4×10 －5 mm 3 / N·m, and the coating can still remain intact after cyclic oxidation at a temperature below 800°C for 100 hours; the wear-resistant and oxidation-resistant quaternary nitride coating on the titanium alloy surface is prepared using a dual cathode glow plasma surface metallurgy equipment equipped with a grid-shaped target, comprising the following steps: Step 1: Substrate surface pretreatment The titanium alloy wire was cut into the size of 15 mm × 15 mm × 3 mm, then polished to 1200 mesh using SiC sandpaper, polished using Cr2O3 suspension, and ultrasonically cleaned in alcohol; Step 2: Use grid target Use single-piece targets instead of conventional round targets, and control the deposition elements by adjusting the composition and quantity of the target; Step 3: Set reasonable tooling spacing Adjust the target spacing and the distance between the target and the substrate to control the sputtering intensity; Step 4: Control the gas pressure, target voltage, substrate voltage, temperature, and time during the preparation process to achieve stable preparation of the coating by controlling the parameters.

2. The wear-resistant and oxidation-resistant quaternary nitride coating on the surface of titanium alloy according to claim 1, characterized in that: The grid-shaped target material described in step 2 is composed of independent pure metal sheets with a purity of not less than 99.9%. The metal sheets are all rectangular thin sheets of 60mm×20mm×3mm, and the short sides are arranged in parallel in an array cycle through stainless steel brackets. The pure metal sheets are pure Zr sheets, pure Ta sheets, and pure Nb sheets, and the number ratio is 1:1:

1.

3. The wear-resistant and oxidation-resistant quaternary nitride coating on the surface of titanium alloy according to claim 1, characterized in that: The tooling spacing described in step 3 includes the following parameters: In the first step, the distance between the target metal sheets is 5~15 mm; In the second step, the distance between the plane where the bottom of the target metal sheet is located and the upper surface of the substrate is 15~20 mm.

4. The wear-resistant and oxidation-resistant quaternary nitride coating on the surface of titanium alloy according to claim 1, characterized in that: In step 4, the gas pressure is 20~25 Pa, the target voltage is controlled at 800V~900V, the substrate voltage is controlled at 350V~400V, the temperature is controlled at 700℃~1000℃, and the holding time is 3~5h.

5. Application of the quaternary nitride coating according to claim 1 on the surface of connecting parts susceptible to wear and oxidation in titanium alloy blades, compressor disks, or titanium alloy pins for engines.

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