Ceramic surface composite coating for resisting hard particle environment and preparation method thereof

Abstract

The invention discloses a ceramic surface composite coating for resisting a hard particle environment, and relates to the technical field of sealing materials, the composite coating comprises a diamond-like carbon bottom layer deposited on a substrate by using acetylene as a carbon source and a diamond-like carbon top layer deposited on the diamond-like carbon bottom layer by using methane as a carbon source, and the thickness ratio of the diamond-like carbon bottom layer to the diamond-like carbon top layer is (0.3-3): 1. The invention further discloses a preparation method of the ceramic surface composite coating for resisting the hard particle environment. The problems that an existing coating is prone to brittle stripping and abrasion in a hard particle environment can be solved, the friction and abrasion performance of a ceramic sealing piece is greatly improved, the service life of a part is prolonged, and the sealing failure risk in the actual working condition is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of sealing materials technology, specifically to a ceramic surface composite coating for resisting hard particle environments and a method for preparing the composite coating. Background Technology

[0002] Silicon carbide and silicon nitride ceramics, due to their combination of high hardness, wear resistance, and corrosion resistance, have become the preferred sealing materials for high-end sealing applications such as aero-engines, chemical pumps and valves, and semiconductor equipment. However, under extreme friction conditions, their surfaces may still experience wear, leading to seal failure. Therefore, improving the wear resistance of the ceramic end face is crucial for achieving a long service life.

[0003] Currently, technicians are using diamond coatings and diamond-like carbon (DLC) coatings to improve the wear resistance of silicon carbide or silicon nitride sealing components. Diamond coatings can significantly improve the tribological properties of silicon carbide or silicon nitride; however, because the rough surface of diamond coatings increases the possibility of seal failure and leakage, complex polishing processes are generally required. Diamond-like carbon coatings are composed of C-sp from the diamond phase. 3 Bonds and graphite phase C-sp 2 Amorphous carbon materials formed by bond mixing have excellent properties such as smooth surface, friction reduction and wear resistance and strong chemical inertness. However, diamond-like carbon coatings have large differences in physical properties from silicon carbide and silicon nitride, and their intrinsic high stress makes them prone to peeling and failure.

[0004] Patent document CN119615105A discloses a composite coating for the surface of ceramic sealing materials. This composite coating includes a diamond transition layer on the ceramic sealing material substrate and a diamond-like carbon (DLC) coating on the diamond transition layer. The preparation method specifically includes the following steps: S1, depositing a diamond coating on the surface of the ceramic sealing material substrate using hot-wire plasma vapor deposition; S2, depositing a DLC coating on the surface of the diamond coating obtained in step S1 using linear ion beam vapor deposition, thus obtaining the composite coating on the surface of the ceramic sealing material. However, in practical applications, the diamond coating surface is rough, making subsequent polishing processes difficult. Furthermore, the diamond layer composite DLC coating scheme involves multiple preparation techniques, placing relatively high demands on equipment and processes.

[0005] Patent document CN120081689A discloses a diamond-like carbon (DLC) coating for a ceramic substrate surface. The preparation method of this coating specifically includes the following steps: S1, using linear ion beam technology with argon as the working gas, etching is performed on the ceramic substrate surface using ionized argon ions to obtain a serrated microstructure; S2, using linear ion beam vapor deposition with acetylene / methane as the working gas, an interfacial mixing layer is formed on the etched ceramic substrate surface by ionizing hydrocarbon precursors, thereby depositing a diamond-like carbon (DLC) coating for use on the ceramic substrate surface. This method improves the film-substrate adhesion between the substrate and the DLC coating by forming microstructures and an interfacial mixing layer on the surface through ion beam etching.

[0006] While the aforementioned diamond-like carbon coatings on ceramic end faces possess sufficient hardness and wear resistance, their toughness is insufficient due to the high stress and brittleness caused by the manufacturing process. Under actual abrasive conditions, they are prone to brittle spalling, leading to coating failure. For example, environments such as sediment, crystalline salt deposits in nuclear power plant seawater circulating pumps, or sludge on the shaft end of wastewater treatment centrifugal pumps, can exacerbate the brittle fracture and delamination problems of the coating.

[0007] In summary, developing protective coating technologies suitable for silicon carbide or silicon nitride ceramic sealing faces that can withstand high-load friction, corrosion, and hard particle erosion over long periods remains a key challenge in this field. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a ceramic surface composite coating for use in environments resistant to hard particles. This coating solves the problems of easy brittle peeling and wear of existing coatings in hard particle environments, significantly improves the friction and wear performance of ceramic seals, extends the service life of components, and effectively reduces the risk of seal failure in actual working conditions.

[0009] The specific technical solution adopted is as follows: A composite coating for ceramic surfaces used in environments resistant to hard particles includes a diamond-like carbon substrate deposited on a substrate using acetylene as a carbon source and a diamond-like carbon substrate deposited on the substrate using methane as a carbon source.

[0010] In this invention, the diamond-like carbon substrate deposited using acetylene as the carbon source gas has a low internal hydrogen content and C-Csp content. 3 The higher number of bonds provides the composite coating with high hardness and strong adhesion to the substrate; the diamond-like carbon top layer deposited using methane as the carbon source gas has a high internal hydrogen content and more CH bonds, giving the composite coating toughness.

[0011] Preferably, the thickness ratio of the diamond-like carbon (DLC) substrate to the DLC top layer is 0.3 to 3:1. Within this thickness ratio range, the high hardness and elastic modulus of the substrate have a more significant load-bearing capacity, while the top layer has a stronger buffering effect on stress concentration in the substrate. The top layer can prevent stress concentration in the substrate and interface under load, and the composite coating is less prone to strip-like peeling and brittle peeling.

[0012] Preferably, the thickness of the diamond-like carbon substrate is 0.2~10 μm. This thickness range can ensure sufficient film-substrate bonding strength while avoiding internal stress accumulation due to excessive thickness. The thickness of the diamond-like carbon top layer is 0.2~10 μm. This thickness can take into account the coating toughness while maintaining a low coefficient of friction and erosion resistance.

[0013] Preferably, the substrate is silicon carbide or silicon nitride.

[0014] Preferably, the composite coating comprises a diamond phase and a graphite phase, with a hardness of 15~25 GPa.

[0015] The present invention also provides a method for preparing the ceramic surface composite coating for resisting hard particle environments, comprising the following steps: (1) A diamond-like carbon substrate was deposited on the substrate surface using acetylene as the carbon source gas by linear ion beam physical vapor deposition. (2) A diamond-like top layer is deposited on a diamond-like bottom layer by using methane as the carbon source gas through linear ion beam physical vapor deposition to obtain the ceramic surface composite coating for resisting hard particle environment.

[0016] Preferably, in step (1), the substrate is etched before depositing the diamond-like carbon (DLC) underlayer. The etching process conditions are: argon flow rate 30~40 sccm, a bias voltage of -50~-350 V applied to the substrate surface, ion source current 0.1-0.8 A, and cavity base vacuum degree 2×10⁻⁶. -5 ~5×10 -5 Torr, etching time 5~60 min.

[0017] By forming a microstructure and interface hybrid layer on the surface through ion beam etching, the influence of interface mismatch between the substrate and diamond-like carbon coating can be reduced, thereby improving the film-substrate adhesion and enhancing the support capacity for the surface diamond-like carbon coating.

[0018] Preferably, in step (1), the substrate is pretreated before depositing the diamond-like carbon substrate. The pretreatment process is as follows: the substrate is ultrasonically cleaned for 5 to 30 minutes using anhydrous ethanol and acetone respectively to remove surface contaminants and improve the performance of the composite coating.

[0019] Preferably, in step (1), the deposition process parameters are: acetylene flow rate 30~40 sccm, a bias voltage of -50~-350 V applied to the substrate surface, ion source current 0.1-0.8 A, and cavity base vacuum degree 2×10 -5 ~5×10 -5 Torr, deposition time 15-750 min.

[0020] Preferably, in step (2), the deposition process parameters are: methane flow rate 30~40 sccm, a bias voltage of -50~-350 V applied to the substrate surface, ion source current 0.1-0.8 A, and cavity base vacuum degree 2×10 -5 ~5×10 -5 Torr, deposition time 15-750 min.

[0021] Preferably, a ball-disc friction and wear tester was used to test the tribological properties of the prepared composite coating under the condition of SiC ball pairing in a mixed solution of 3.5 wt% NaCl and 4 wt% SiO2. The test results were: friction coefficient 0.05~0.12, wear rate 5×10⁻⁶. -8 ~2×10 -7 mm 3 / N -1 m -1 .

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In this invention, the diamond-like carbon substrate with acetylene as the carbon source has strong bonding with the matrix and has little difference in physical properties from the diamond-like carbon substrate with methane as the carbon source. Using it as an intermediate transition layer can improve the bonding strength between the film and the substrate while reducing the internal stress of the composite coating. In addition, the diamond-like carbon substrate with methane as the carbon source is located on the surface of the composite coating, which can make the coating more resistant to the impact of hard particles.

[0023] (2) By using a diamond-like carbon layer deposited with acetylene as the carbon source as the bottom layer and a diamond-like carbon layer deposited with methane as the top layer, the present invention can improve the toughness of the composite coating while having both high hardness and strong film-substrate bonding force, and solve the problems of easy brittle peeling and easy wear of existing coatings when subjected to erosion. Compared with diamond-like carbon coatings deposited with acetylene or methane as the carbon source, it has better friction and wear resistance.

[0024] (3) The composite coating preparation method of the present invention is simple and stable. By controlling the hydrogen content of the coating, a composite structure with chemical composition gradient and mechanical property gradient is formed, thereby optimizing the hardness and toughness of the composite coating. This avoids the problem of unstable coating performance caused by complex control of multiple parameters such as bias voltage, power supply and gas flow rate in traditional processes, and breaks through the limitations of existing preparation technologies on the range of coating performance control. In addition, during the preparation process, the etching and deposition steps are both carried out using linear ion beam physical vapor deposition, which can be continuously processed in the same chamber, making it easy to realize the industrial-scale preparation of coatings. Attached Figure Description

[0025] Figure 1 This is a SEM image of the composite coating in Example 1.

[0026] Figure 2 The images show two-dimensional distribution diagrams of the wear track morphology and wear track depth of the coatings in Example 1, Comparative Example 1, and Comparative Example 2.

[0027] Figure 3 The graphs show the change in the coefficient of friction of the coatings in Example 1, Comparative Example 1, and Comparative Example 2 as a function of friction time.

[0028] Figure 4 The image shows a TEM image of the coating in Comparative Example 1 after 1000 s of rubbing. The Pt and carbon layers were used to protect the area to be observed during FIB sample preparation.

[0029] Figure 5 The graph shows the friction coefficient and wear rate results of the composite coatings in Examples 1-3.

[0030] Figure 6 The graph shows the hydrogen content results of the coatings in Examples 1-3 and Comparative Examples 1-2. Detailed Implementation

[0031] The present invention will be further illustrated below with reference to the embodiments and accompanying drawings. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0032] Example 1 In this embodiment, the diamond-like carbon substrate is deposited on the surface of a SiC substrate using acetylene as the carbon source gas and linear ion beam physical vapor deposition (LINEPS). The diamond-like carbon substrate is deposited on the surface of the diamond-like carbon substrate using methane as the carbon source gas and LINEPS. The thickness of the diamond-like carbon substrate is approximately 0.2 μm, and the thickness of the diamond-like carbon substrate is approximately 0.6 μm.

[0033] The preparation method includes the following steps: S11. The SiC substrate is ultrasonically cleaned using ethanol and acetone for 30 minutes each, then removed and dried.

[0034] S12. Linear ion beam physical vapor deposition (LPV) is employed, using argon as the working gas. A bias voltage of -200 V is applied to the SiC substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 Torr, with a gas flow rate of 38 sccm, was used to etch the substrate surface using ionized argon ions, and this process was maintained for 30 minutes.

[0035] S13. Linear ion beam physical vapor deposition (LPV) is employed, using acetylene as the working gas. A bias voltage of -100 V is applied to the SiC substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 A diamond-like carbon (DLC) substrate with a thickness of 0.2 μm was deposited on a SiC substrate using a Torr gas flow rate of 38 sccm and a deposition time of 15 minutes.

[0036] S14. Linear ion beam physical vapor deposition is employed, using methane as the working gas, with a bias voltage of -100 V, an ion source current of 0.2 A, and a chamber floor vacuum of 3 × 10⁻⁶. -5 Torr, with a gas flow rate of 38 sccm and a deposition time of 108 minutes, deposited a 0.6 μm thick diamond-like carbon top layer on a diamond-like carbon base layer.

[0037] The deposition thickness is calculated as follows: a three-step method of "pre-experiment-calibration-calculation" is adopted. First, under specific process parameters, a short-term pre-deposition is performed on a substrate of the same material to ensure environmental stability. Then, a step meter is used to measure the film thickness at five points from the center to the edge of the sample. After removing outliers, the average value is taken to reduce the error caused by substrate tilt and edge effect. Finally, the deposition rate is obtained by dividing the average thickness by the deposition time. During the subsequent formal coating, the deposition time is calculated according to the target thickness and deposition rate.

[0038] like Figure 1 The image shows the SEM image of the composite coating obtained in this embodiment. The composite coating, which is deposited sequentially with acetylene and methane as carbon sources, exhibits a continuous, uniform, and dense morphology. No interface delamination, cracks, or abrupt changes in composition were observed, confirming that the obtained composite coating has a high degree of structural matching and excellent bonding strength.

[0039] The carbon phase composition and hydrogen content of the coating were tested using Raman spectroscopy. The results showed that the composite coating prepared in this embodiment included a diamond phase and a graphite phase, with a hydrogen content of 24.83 at%. Figure 6 As shown.

[0040] The hardness of the coating was tested using the nanoindentation method, and the result was 17.6 GPa.

[0041] A ball-disc friction and wear tester was used, with SiC balls as the grinding pair, to conduct an erosion wear test on the prepared composite coating for 1 hour in a mixed solution containing 3.5 wt% NaCl + 4 wt% SiO2 particles under a load of 10 N. Figure 2 As shown, the composite coating prepared in this embodiment exhibits narrow wear marks and no significant peeling after 1 hour of friction. The stable coefficient of friction of the composite coating was tested to be 0.07, as shown in the results. Figure 3 As shown, the average wear rate is 1.21 × 10⁻⁶. -7 mm 3 / (Nm), the result is as follows Figure 5 As shown, this demonstrates its excellent friction-reducing and wear-resistant properties.

[0042] Example 2 In this embodiment, the diamond-like carbon substrate uses acetylene as the carbon source gas and is deposited on the surface of a Si3N4 substrate using linear ion beam physical vapor deposition (LINEPS). The diamond-like carbon substrate uses methane as the carbon source gas and is deposited on the surface of the diamond-like carbon substrate using LINEPS. The thickness of the diamond-like carbon substrate is approximately 0.4 μm, and the thickness of the diamond-like carbon substrate is approximately 0.4 μm.

[0043] The preparation method includes the following steps: S21. The Si3N4 substrate is ultrasonically cleaned by ultrasonic cleaning with ethanol and acetone for 30 minutes each, and then removed and dried.

[0044] S22. Linear ion beam physical vapor deposition (LPV) is employed, using argon as the working gas. A bias voltage of -200 V is applied to the Si3N4 substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 Torr, with a gas flow rate of 38 sccm, is used to etch the substrate surface using ionized argon ions, and this process is maintained for 30 minutes.

[0045] S23. Linear ion beam physical vapor deposition (LPV) is employed, using acetylene as the working gas. A bias voltage of -100 V is applied to the Si3N4 substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 A diamond-like carbon (DLC) substrate with a thickness of 0.4 μm was deposited on a Si3N4 substrate using a Torr gas flow rate of 38 sccm and a deposition time of 30 minutes.

[0046] S24. Linear ion beam physical vapor deposition is employed, using methane as the working gas, with a bias voltage of -100 V, an ion source current of 0.2 A, and a chamber floor vacuum of 3 × 10⁻⁶. -5Torr, with a gas flow rate of 38 sccm and a deposition time of 72 minutes, deposited a 0.4 μm thick diamond-like top layer on a diamond-like bottom layer.

[0047] The composite coating prepared in this embodiment includes a diamond phase and a graphite phase, with a hydrogen content of 24.61 at%. The results are as follows: Figure 6 As shown, the hardness is 19.5 GPa.

[0048] The composite coating obtained in this embodiment has an average friction coefficient of 0.07 and an average wear rate of 1.16 × 10⁻⁶. -7 mm 3 / (Nm), the result is as follows Figure 5 As shown.

[0049] Example 3 In this embodiment, the diamond-like carbon substrate is deposited on the surface of a SiC substrate using acetylene as the carbon source gas and linear ion beam physical vapor deposition (LINEPS). The diamond-like carbon substrate is deposited on the surface of the diamond-like carbon substrate using methane as the carbon source gas and LINEPS. The thickness of the diamond-like carbon substrate is approximately 0.6 μm, and the thickness of the diamond-like carbon substrate is approximately 0.2 μm.

[0050] The preparation method includes the following steps: S31. The SiC substrate is ultrasonically cleaned using ethanol and acetone for 30 minutes each, and then removed and dried.

[0051] S32. Linear ion beam physical vapor deposition is employed, using argon as the working gas. A bias voltage of -200 V is applied to the SiC substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 Torr, with a gas flow rate of 38 sccm, was used to etch the substrate surface using ionized argon ions, and this process was maintained for 30 minutes.

[0052] S33. Linear ion beam physical vapor deposition is employed, using acetylene as the working gas. A bias voltage of -100 V is applied to the SiC substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 A diamond-like carbon (DLC) substrate with a thickness of 0.6 μm was deposited on a SiC substrate using a Torr gas flow rate of 38 sccm and a deposition time of 45 minutes.

[0053] S34. Linear ion beam physical vapor deposition is employed, using methane as the working gas, with a bias voltage of -100 V, an ion source current of 0.2 A, and a chamber floor vacuum of 3 × 10⁻⁶. -5Torr, with a gas flow rate of 38 sccm and a deposition time of 36 minutes, deposited a 0.2 μm thick diamond-like top layer on a diamond-like bottom layer.

[0054] The composite coating prepared in this embodiment includes a diamond phase and a graphite phase, with a hydrogen content of 24.20 at%, as shown in the following figures. Figure 6 As shown, the hardness is 21.3 GPa.

[0055] The composite coating obtained in this embodiment has an average friction coefficient of 0.07 and an average wear rate of 1.38 × 10⁻⁶. -7 mm 3 / (Nm), the result is as follows Figure 5 As shown.

[0056] Comparative Example 1 This comparative example uses only acetylene as the carbon source to deposit a single-layer diamond-like coating with a thickness of approximately 0.8 μm.

[0057] The preparation method includes the following steps: S41. The SiC substrate is ultrasonically cleaned using ethanol and acetone for 30 minutes each, and then removed and dried.

[0058] S42. Linear ion beam physical vapor deposition is employed, using argon as the working gas. A bias voltage of -200 V is applied to the SiC substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 Torr, with a gas flow rate of 38 sccm, was used to etch the substrate surface using ionized argon ions, and this process was maintained for 30 minutes.

[0059] S43. Linear ion beam physical vapor deposition is employed, using acetylene as the working gas. A bias voltage of -100 V is applied to the SiC substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 A diamond-like carbon coating with a thickness of 0.8 μm was deposited on a SiC substrate using a Torr gas flow rate of 38 sccm and a deposition time of 60 minutes.

[0060] The coating prepared in this comparative example includes diamond and graphite phases, with a hydrogen content of 15.6 at%, and the results are as follows: Figure 6 As shown, the hardness is 25 GPa.

[0061] like Figure 2 As shown, the wear depth of the coating obtained in this comparative example reached 5 μm; Figure 3 As shown, the stable friction coefficient of the coating is 0.12.

[0062] Depend on Figure 4The cross-sectional TEM image shows that after 1000 s of friction, the coating exhibits obvious brittle spalling with a cross-sectional pattern, indicating that the coating has poor toughness.

[0063] Comparative Example 2 This comparative example uses only methane as the carbon source to deposit a single-layer diamond-like carbon coating with a thickness of approximately 0.8 μm.

[0064] The preparation method includes the following steps: S51. The SiC substrate is ultrasonically cleaned by ultrasonic cleaning with ethanol and acetone for 30 minutes each, and then removed and dried.

[0065] S52. Linear ion beam physical vapor deposition is employed, using argon as the working gas. A bias voltage of -200 V is applied to the SiC substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 Torr, with a gas flow rate of 38 sccm, was used to etch the substrate surface using ionized argon ions, and this process was maintained for 30 minutes.

[0066] S53. Linear ion beam physical vapor deposition is employed, using methane as the working gas. A bias voltage of -100 V is applied to the SiC substrate, the ion source current is 0.2 A, and the cavity floor vacuum is 3 × 10⁻⁶. -5 A diamond-like carbon coating with a thickness of 0.8 μm was deposited on a SiC substrate using a Torr gas flow rate of 38 sccm and a deposition time of 144 minutes.

[0067] The coating prepared in this comparative example includes diamond and graphite phases, with a hydrogen content of 25.1 at%, and the results are as follows: Figure 6 As shown, the hardness is 15 GPa.

[0068] like Figure 2 As shown, the coating obtained in this comparative example exhibited strip-like peeling that penetrated the coating at the wear mark location. Compared to Example 1, the coating showed peeling failure. The maximum depth of the wear mark measured by the profilometer was 798 nm, which is comparable to the coating thickness. The stable friction coefficient of the coating was 0.07, as shown in the results. Figure 3 As shown.

[0069] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A composite coating for ceramic surfaces resistant to hard particle environments, characterized in that, This includes a diamond-like carbon substrate deposited on a matrix using acetylene as the carbon source and a diamond-like carbon substrate deposited on top of the diamond-like carbon substrate using methane as the carbon source.

2. The ceramic surface composite coating for resisting hard particle environments according to claim 1, characterized in that, The thickness ratio of the diamond-like carbon (DLC) bottom layer to the diamond-like carbon top layer is 0.3 to 3:

1.

3. The ceramic surface composite coating for resisting hard particle environments according to claim 2, characterized in that, The thickness of the diamond-like carbon (DLC) bottom layer is 0.2~10 μm, and the thickness of the diamond-like carbon top layer is 0.2~10 μm.

4. The ceramic surface composite coating for resisting hard particle environments according to claim 1, characterized in that, The substrate is silicon carbide or silicon nitride.

5. The ceramic surface composite coating for resisting hard particle environments according to claim 1, characterized in that, The composite coating comprises a diamond phase and a graphite phase, with a hardness of 15~25 GPa.

6. The method for preparing a ceramic surface composite coating for resisting hard particle environments according to any one of claims 1-5, comprising the following steps: (1) A diamond-like carbon substrate was deposited on the substrate surface using acetylene as the carbon source gas by linear ion beam physical vapor deposition. (2) A diamond-like top layer is deposited on a diamond-like bottom layer by using methane as the carbon source gas through linear ion beam physical vapor deposition to obtain the ceramic surface composite coating for resisting hard particle environment.

7. The method for preparing a ceramic surface composite coating for resisting hard particle environments according to claim 6, characterized in that, In step (1), the substrate is etched before depositing the diamond-like carbon (DLC) underlayer. The etching process conditions are: argon flow rate 30~40 sccm, a bias voltage of -50~-350 V applied to the substrate surface, ion source current 0.1-0.8 A, and cavity base vacuum degree 2×10⁻⁶. -5 ~5×10 -5 Torr, etching time 5~60 min.

8. The method for preparing a ceramic surface composite coating for resisting hard particle environments according to claim 6, characterized in that, In step (1), the deposition process parameters are: acetylene flow rate 30~40 sccm, a bias voltage of -50~-350V applied to the substrate surface, ion source current 0.1-0.8 A, and a chamber base vacuum of 2×10⁻⁶. -5 ~5×10 -5 Torr, deposition time 15-750 min.

9. The method for preparing a ceramic surface composite coating for resisting hard particle environments according to claim 6, characterized in that, In step (2), the deposition process parameters are: methane flow rate 30~40 sccm, a bias voltage of -50~-350V applied to the substrate surface, ion source current 0.1-0.8 A, and cavity base vacuum degree 2×10 -5 ~5×10 -5 Torr, deposition time 15-750 min.

10. The method for preparing a ceramic surface composite coating for resisting hard particle environments according to claim 6, characterized in that, The tribological properties of the prepared composite coating were tested using a ball-disc tribological tester under conditions of SiC ball pairing in a mixed solution of 3.5 wt% NaCl and 4 wt% SiO2. The test results were: friction coefficient 0.05~0.12, wear rate 5×10⁻⁶. -8 ~2×10 -7 mm 3 / N -1 m -1 .

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