A wear-resistant and oxidation-resistant ceramic coating for titanium-aluminum alloy surface and its preparation method

Abstract

This invention relates to the field of metal surface treatment technology, and provides a wear-resistant and oxidation-resistant ceramic coating for titanium-aluminum alloy surfaces and its preparation method. The phase composition of the ceramic coating includes Ti5Si3, TiC, and Ti2AlC, wherein Ti5Si3 is the continuous phase, and TiC and Ti2AlC are the dispersed phases. The continuous phase Ti5Si3 is in direct contact with the titanium-aluminum alloy substrate and forms a metallurgical bond, while the dispersed phases TiC and Ti2AlC are dispersedly distributed within the coating. The thickness of the ceramic coating is 1–3 μm. The ceramic coating formed by this invention has a dense structure, good bonding with the substrate, and excellent wear resistance. It also effectively inhibits the diffusion of oxygen into the substrate, thereby improving the service performance of titanium-aluminum alloys in high-temperature oxidizing environments. The preparation method is low-cost, simple, flexible, and highly controllable, making it suitable for high-temperature surface protection of titanium-aluminum alloy components.

Description

Technical Field

[0001] This invention belongs to the field of metal surface treatment technology, and particularly relates to a wear-resistant and oxidation-resistant ceramic coating for titanium-aluminum alloy surfaces and its preparation method. Background Technology

[0002] Titanium-aluminum alloys, as a type of high-temperature lightweight alloy, have attracted widespread attention due to their low density, high specific strength, excellent creep resistance, and ability to retain high-temperature elastic modulus. They have become ideal materials for applications with stringent requirements for lightweighting and thermal efficiency, such as aerospace propulsion systems, automotive turbochargers, and advanced gas turbines. However, titanium-aluminum alloys have significantly insufficient oxidation resistance at temperatures exceeding 800 °C, which severely restricts their further high-temperature applications.

[0003] Under high-temperature oxidation conditions, a mixed oxide layer typically forms on the surface of titanium-aluminum alloys, consisting of non-protective porous TiO2 and discontinuous Al2O3. TiO2 grows rapidly but is prone to peeling, making it difficult to provide effective long-term protection to the substrate. To improve the service performance of titanium-aluminum alloys in high-temperature environments, constructing a protective coating with good density and stability on its surface has become a commonly used technique. Existing high-temperature treatment methods for titanium-aluminum alloy surface protection often require the simultaneous introduction of multiple materials to obtain a surface protective layer with a certain degree of density. In practical applications, these multi-component material systems are highly dependent on the raw material ratios and processing conditions. The synergistic effect between different components narrows the process window, posing challenges to stable preparation and reproducible implementation. Summary of the Invention

[0004] The purpose of this invention is to provide a wear-resistant and oxidation-resistant ceramic coating for titanium-aluminum alloy surfaces and its preparation method, thereby addressing the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: On the one hand, a wear-resistant and oxidation-resistant ceramic coating for titanium-aluminum alloy surfaces, wherein the phase composition of the ceramic coating includes Ti5Si3, TiC and Ti2AlC, wherein Ti5Si3 is a continuous phase and TiC and Ti2AlC are dispersed phases; The continuous phase Ti5Si3 is in direct contact with the titanium-aluminum alloy matrix and forms a metallurgical bond, while the dispersed phases TiC and Ti2AlC are dispersedly distributed inside the coating. The thickness of the ceramic coating is 1–3 μm.

[0006] On the other hand, a method for preparing a wear-resistant and oxidation-resistant ceramic coating on a titanium-aluminum alloy surface includes the following steps: (1) Pre-treat the titanium-aluminum alloy substrate, including grinding and cleaning; (2) Place the pretreated titanium-aluminum alloy matrix into a crucible containing SiC powder, fill and compact it so that the titanium-aluminum alloy matrix and SiC powder are in full contact and the titanium-aluminum alloy matrix is ​​embedded in SiC powder. (3) The crucible is placed in a vacuum atmosphere for high-temperature treatment, and then cooled to room temperature with the furnace to form a wear-resistant and oxidation-resistant ceramic coating on the surface of the titanium-aluminum alloy substrate.

[0007] Compared with the prior art, the present invention has the following advantages: Stable structure: The ceramic coating prepared in the embodiments of the present invention forms a metallurgical bond with the titanium-aluminum alloy substrate, with high interfacial bonding strength, continuous and uniform coating structure, no micro-cracks and pores and other defects, and good structural integrity. Strong oxidation resistance: The ceramic coating prepared in the embodiments of the present invention has better oxidation resistance than the untreated substrate material under high temperature oxidation environment. Specifically, under the same oxidation conditions, the oxidation weight gain per unit area of ​​the coated sample is significantly lower than that of the titanium-aluminum substrate. Improved wear resistance: The ceramic coating prepared in the embodiments of the present invention exhibits a low and stable coefficient of friction under friction and wear conditions, and a small wear rate, thereby effectively improving the wear resistance of titanium-aluminum alloy during service. Simple process: The preparation process of the present invention is simple and efficient, and ceramic coatings of different thicknesses can be prepared by adjusting the high-temperature thermal diffusion time and temperature. Attached Figure Description

[0008] Figure 1 This is a cross-sectional scan of the ceramic coating provided in Embodiment 1 of the present invention; Figure 2 The XRD pattern of the ceramic coating provided in Embodiment 1 of the present invention; Figure 3 This is a cross-sectional scan of the ceramic coating provided in Embodiment 2 of the present invention; Figure 4 This is a cross-sectional scan of the ceramic coating provided in Embodiment 3 of the present invention; Figure 5 This is a cross-sectional scan of the titanium-aluminum alloy component provided in Comparative Example 1 of the present invention; Figure 6 This is a cross-sectional scan of the ceramic coating provided in Comparative Example 2 of the present invention; Figure 7 This is a cross-sectional scan of the ceramic coating provided in Comparative Example 3 of the present invention. Detailed Implementation

[0009] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0010] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0011] Example 1: A wear-resistant and oxidation-resistant ceramic coating for titanium-aluminum alloy surfaces, the preparation method of which specifically includes the following steps: (1) The titanium-aluminum alloy components are ground and then cleaned to remove surface stains; (2) The pretreated titanium-aluminum alloy component is embedded in SiC powder, placed in a crucible, and the crucible is placed in a vacuum furnace for vacuum high-temperature treatment; (3) The vacuum furnace is heated to 1000 ℃ at a heating rate of 10 ℃ / min and held for 60 min. During the high-temperature diffusion process, a composite ceramic coating composed of Ti5Si3, TiC and Ti2AlC is formed, wherein TiC and Ti2AlC particles are dispersed in the continuous phase Ti5Si3. Then, the furnace is cooled to room temperature, and the titanium-aluminum alloy component is taken out for cleaning. A ceramic coating is formed on its surface. The ceramic coating thickness is approximately 1.81 μm. Analysis of this ceramic coating yielded the following cross-sectional scan image: Figure 1 As shown, the XRD pattern is as follows Figure 2 As shown, the continuous phase in the ceramic coating is Ti5Si3 (white-gray structure), and the dispersed phase is TiC / Ti2AlC (black-gray structure). High-temperature oxidation tests were conducted on the titanium-aluminum alloy component: after oxidation at 900 °C in air for 600 min, the weight gain per unit area was 0.816 mg / cm². 2 Compared to untreated titanium-aluminum alloy components under the same conditions, the oxidation weight gain was reduced by approximately 45.3%; The friction and wear performance of the titanium-aluminum alloy component was tested: using GCr15 steel balls as the friction pair, under the conditions of a load of 2N, a frequency of 4 Hz, and a test time of 10 min, the average friction coefficient was obtained as 0.426, and the wear rate was 12.87 × 10⁻⁶. -6 mm 3 / Nm, showing good wear resistance.

[0012] Example 2: A wear-resistant and oxidation-resistant ceramic coating for titanium-aluminum alloy surfaces, the preparation method of which specifically includes the following steps: Steps (1) and (2) are the same as in Example (1); (3) Heat the vacuum furnace to 1000 ℃ at a heating rate of 8 ℃ / min and hold for 240 min. Then cool it to room temperature with the furnace. Take out the titanium-aluminum alloy component and clean it. A ceramic coating is formed on its surface. The ceramic coating has a thickness of approximately 2.01 μm. Analysis of this ceramic coating yielded the following cross-sectional scan image: Figure 3 As shown, the continuous phase in the ceramic coating is Ti5Si3 (white-gray structure), and the dispersed phase is TiC / Ti2AlC (black-gray structure). High-temperature oxidation tests were conducted on the titanium-aluminum alloy component: after oxidation at 900 °C in air for 600 min, the weight gain per unit area was 0.695 mg / cm². 2 Compared to untreated titanium-aluminum alloy components under the same conditions, the oxidation weight gain was reduced by approximately 53.4%; The friction and wear performance of the titanium-aluminum alloy component was tested: using GCr15 steel balls as the friction pair, under the conditions of a load of 2N, a frequency of 4 Hz, and a test time of 10 min, the average friction coefficient was obtained as 0.391, and the wear rate was 8.7 × 10⁻⁶. -6 mm 3 / Nm, showing good wear resistance.

[0013] Example 3: A wear-resistant and oxidation-resistant ceramic coating for titanium-aluminum alloy surfaces, the preparation method of which specifically includes the following steps: Steps (1) and (2) are the same as in Example (1); (3) Heat the vacuum furnace to 1100 ℃ at a heating rate of 10 ℃ / min and hold for 180 min. Then cool it to room temperature with the furnace. Take out the titanium-aluminum alloy component and clean it. A ceramic coating is formed on its surface. The ceramic coating has a thickness of approximately 2.52 μm. Analysis of this ceramic coating yielded the following cross-sectional scan image: Figure 4 As shown, the continuous phase in the ceramic coating is Ti5Si3 (white-gray structure), and the dispersed phase is TiC / Ti2AlC (black-gray structure). High-temperature oxidation tests were conducted on the titanium-aluminum alloy component: after oxidation at 900 °C in air for 600 min, the weight gain per unit area was 0.606 mg / cm². 2 Compared to untreated titanium-aluminum alloy components under the same conditions, the oxidation weight gain was reduced by approximately 59.4%; The friction and wear performance of the titanium-aluminum alloy component was tested: using GCr15 steel balls as the friction pair, under the conditions of a load of 2N, a frequency of 4 Hz, and a test time of 10 min, the average friction coefficient was obtained as 0.330, and the wear rate was 3.40 × 10⁻⁶. -6 mm 3 / Nm, showing good wear resistance.

[0014] Comparative Example 1: A surface treatment method for titanium-aluminum alloy, comprising the following steps: Steps (1) and (2) are the same as in Example (1); (3) The vacuum furnace was heated to 600 ℃ at a heating rate of 6 ℃ / min and held for 300 min. Then it was cooled to room temperature with the furnace. The titanium-aluminum alloy component was taken out and cleaned. No obvious coating appeared on its surface. The cross-sectional scan diagram of the titanium-aluminum alloy component was obtained through analysis. Figure 5 As shown.

[0015] Comparative Example 2: A surface treatment method for titanium-aluminum alloy, comprising the following steps: Steps (1) and (2) are the same as in Example (1); (3) The vacuum furnace was heated to 700 °C at a heating rate of 7 °C / min and held for 300 min. Then it was cooled to room temperature with the furnace. The titanium-aluminum alloy component was taken out and cleaned. A ceramic coating with a thickness of about 1.32 μm was formed on its surface. The ceramic coating was analyzed, and the cross-sectional scan image was obtained as follows. Figure 6 As shown; High-temperature oxidation tests were conducted on the titanium-aluminum alloy component: after oxidation at 900 °C in air for 600 min, the weight gain per unit area was 1.591 mg / cm². 2 The oxidation weight gain per unit area of ​​the titanium-aluminum alloy component under the same oxidation conditions without any treatment was 1.623 mg / cm². 2 The results are similar, indicating that the antioxidant capacity was not significantly improved under these conditions. The friction and wear performance of the titanium-aluminum alloy component was tested: using GCr15 steel balls as the friction pair, under the conditions of a load of 2N, a frequency of 4 Hz, and a test time of 10 min, the average friction coefficient was obtained as 0.591, and the wear rate was 33.81 × 10⁻⁶. -6 mm 3 / Nm.

[0016] Comparative Example 3: A surface treatment method for titanium-aluminum alloy, comprising the following steps: Steps (1) and (2) are the same as in Example (1); (3) The vacuum furnace was heated to 1200 °C at a heating rate of 10 °C / min and held for 60 min. Then the furnace was cooled to room temperature. The titanium-aluminum alloy components were taken out and cleaned. A ceramic coating with a thickness of about 2.98 μm was formed on its surface. The ceramic coating was analyzed, and the cross-sectional scan image was obtained as follows. Figure 7 As shown; High-temperature oxidation tests were conducted on the titanium-aluminum alloy component: after oxidation at 900 °C in air for 600 min, the weight gain per unit area was 1.247 mg / cm². 2 The test results showed that the coating formed under these treatment conditions had limited effect on inhibiting high-temperature oxidation and failed to achieve the desired antioxidant properties.

[0017] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A wear-resistant and oxidation-resistant ceramic coating for titanium-aluminum alloy surfaces, characterized in that, The phase composition of the ceramic coating includes Ti5Si3, TiC and Ti2AlC, wherein Ti5Si3 is the continuous phase and TiC and Ti2AlC are the dispersed phases; The continuous phase Ti5Si3 is in direct contact with the titanium-aluminum alloy matrix and forms a metallurgical bond, while the dispersed phases TiC and Ti2AlC are dispersedly distributed inside the coating. The thickness of the ceramic coating is 1–3 μm; The method for preparing the wear-resistant and oxidation-resistant ceramic coating on the surface of the titanium-aluminum alloy includes the following steps: (1) Pre-treat the titanium-aluminum alloy substrate, including grinding and cleaning; (2) Place the pretreated titanium-aluminum alloy matrix into a crucible containing SiC powder, fill and compact it so that the titanium-aluminum alloy matrix is ​​in full contact with the SiC powder and the titanium-aluminum alloy matrix is ​​embedded in the SiC powder. (3) The crucible is placed in a vacuum atmosphere for high-temperature treatment, and then cooled to room temperature with the furnace to form a wear-resistant and oxidation-resistant ceramic coating on the surface of the titanium-aluminum alloy substrate. In step (2), the particle size of the SiC powder is 0.3~10 μm; In step (3), the high temperature treatment is 800-1100 ℃, the time is 60~300 min, and the heating rate is 5-11℃ / min.

2. The wear-resistant and oxidation-resistant ceramic coating on the surface of titanium-aluminum alloy according to claim 1, characterized in that, In step (3), the vacuum degree of the vacuum atmosphere is 5×10⁻⁶. -3 ~5×10 -4 Pa.

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