High toughness heat resistant ceramic coating and method of making same

Abstract

The application provides a high-toughness heat-resistant ceramic coating and a preparation method thereof, relates to the field of coating preparation, and comprises the following steps: S1, pretreating a substrate and fixing the substrate on a substrate table; S2, placing target materials on target positions respectively; S3, bias cleaning the substrate by ionizing an inert gas; S4, sputtering a 80-100nm-thick pure Ti transition layer on the surface of the substrate; and S5, forming an AlCrSiTiBN anti-oxidation coating layer on the pure Ti transition layer. The coating provided by the application solves the problem of easy oxidation failure of the coating at high temperatures on the basis of maintaining excellent mechanical properties, and provides a new idea for the application of the protective coating of the surface of a titanium alloy of an aero-engine compressor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-toughness high-temperature-resistant protective coating preparation, in particular to a high-toughness high-temperature-resistant ceramic coating applied to the surface of a titanium alloy of an aircraft engine compressor and a preparation method thereof. BACKGROUND

[0002] With the continuous development of aircraft engine and gas turbine technology and the continuous improvement of use requirements, the working temperature is also gradually increased, the service environment of the compressor blade tends to be high temperature, complex stress, high corrosion, etc., the blade needs to have the ability to withstand oxidation, corrosion, high-speed airflow scouring, high-temperature creep and thermal mechanical fatigue long-term work without failure, and the preparation of a suitable protective coating on the blade is an effective and feasible way.

[0003] The outlet temperature of the domestic compressor is generally 400-600 DEG C, and the outlet temperature of the advanced engine has exceeded 650 DEG C, mainly existing high-temperature oxidation problem, and the adaptability of the compressor coating in this temperature range is less. In addition, with the increasing of the thrust-to-weight ratio, it is expected that the outlet temperature of the compressor of the fifth generation aircraft engine will reach about 800 DEG C, and the performance of the protective coating will be sharply degraded in the harsh working environment of high temperature, high pressure and high speed, and the protective performance will be invalid. Therefore, the coating with excellent mechanical properties and high-temperature oxidation resistance is the guarantee of high-performance compressor blades, and improving the wear resistance, hardness and oxidation resistance is the key.

[0004] Previous studies are mainly limited to binary and ternary nitride coatings, such as TiBN, which is a ternary coating formed by adding B element to TiN. The incorporation of B can refine the coating grains, and the hardness is significantly improved. According to the previous research, although the TiBN coating has good mechanical strength, its oxidation resistance cannot meet the service requirements of the compressor, and the incorporation of elements with good oxidation resistance will cause the hardness of the coating to drop sharply. With the further improvement of service temperature, higher requirements for the oxidation resistance of the protective coating are put forward, so it is urgent to develop a new system with hardness and oxidation resistance to adapt to more severe service environment. SUMMARY

[0005] In order to solve the problems in the prior art, the present application improves the original TiBN coating and designs a new type of high-toughness high-temperature-resistant ceramic coating for the surface of a titanium alloy of an aircraft engine compressor. While retaining the high hardness of the TiBN coating, the oxidation resistance of the TiBN coating is improved, avoiding the phenomenon that the hardness of the coating is sharply reduced due to the introduction of oxidation-resistant elements, so that the problem of failure and degradation of the protective performance of the traditional nitride coating in high-temperature service environment is improved. Specifically:

[0006] A method for preparing a ceramic coating for an aero-engine compressor surface, comprising:

[0007] Step S1, polishing the substrate, then cleaning it with organic solvent and deionized water, and fixing the dried substrate on a substrate table, and finally placing it in the chamber of a coating device;

[0008] Step S2, placing AlCrSi target, Ti target and TiB2 target on the target position respectively;

[0009] Step S3, vacuumizing the chamber to a vacuum degree of 1.8×10 -3 Pa, then heating the chamber to a deposition temperature of 300-400℃, adjusting the chamber pressure to 1 Pa by introducing inert gas, setting the bias voltage of the substrate table to -950 V, and etching for 10-20 min; this step is to clean the substrate by ionizing inert gas;

[0010] Step S4, controlling the Ti target power to be between 400-480 W, adjusting the flow of inert gas Ar to stabilize the chamber pressure at 0.18-0.21 Pa, and sputtering a 80-100 nm thick pure Ti transition layer on the substrate surface; the transition layer is mainly used to realize the adhesion between the substrate and the oxidation-resistant coating, and prevent the coating from delaminating and falling off:

[0011] Step S5, further introducing inert gas and opening the N2 flow controller switch, controlling the chamber pressure to be 0.18-0.21 Pa, setting the bias voltage of the substrate table to -110 V and the rotation speed to 23 rpm, controlling the power of the AlCrSi target to be between 160 and 240 W, and the power of the TiB2 target to be between 65 and 85 W, and depositing for 2-3 h at the deposition temperature to form an AlCrSiTiBN oxidation-resistant coating on the pure Ti transition layer.

[0012] Preferably, in step S1, the organic solvent is selected from acetone and alcohol; and the cleaning method is selected from ultrasonic cleaning.

[0013] Preferably, in step S1, the substrate is selected from one of single crystal Si, single crystal Al2O3 and 304 stainless steel.

[0014] Preferably, in step S2, the AlCrSi target is placed on the radio frequency target position, the chemical composition ratio of Al, Cr and Si in the target is 1:1:1, the Ti target and the TiB2 target are placed on the direct current target position, and the purity of the targets reaches 99.99%, and the size of the targets is φ76.2×5 mm. Generally, metal targets with good electrical conductivity are placed on the direct current target position, and materials with poor electrical conductivity are placed on the radio frequency target position, and generally, the sputtering efficiency of the direct current target is higher than that of the radio frequency target.

[0015] Preferably, in step S3, the inert gas is selected from argon.

[0016] Preferably, in step S5, 30 sccm of Ar and 10 sccm of N2 are introduced at a ratio of 3:1, the gas pressure is stabilized at 0.18 Pa, the power of the AlCrSi target is controlled at 200 W, the power of the TiB2 target is controlled at 80 W, and the deposition is performed for 3 h at the deposition temperature.

[0017] Further, the application also provides a ceramic coating, comprising a substrate, a pure Ti transition layer, and an AlCrSiTiBN oxidation-resistant coating, which can resist oxidation at 800 DEG C and maintain high strength and high toughness.

[0018] The technical scheme provided by the embodiments of the application has at least the following beneficial effects:

[0019] The ceramic coating with the substrate, the pure Ti transition layer, and the AlCrSiTiBN layer is designed by using the magnetron sputtering method, so that the coating material has the excellent properties of high strength, high toughness, and high-temperature oxidation resistance, and the problem of easy oxidation failure of the coating at high temperature (the coating can maintain high strength and high toughness at 800 DEG C) is effectively solved on the basis of maintaining the mechanical properties of the ceramic coating. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort.

[0021] Figure 1 Fig. 1 is a schematic diagram of the internal structure of a magnetron sputtering coating instrument chamber according to the application;

[0022] Figure 2 Fig. 2 is a schematic diagram of the structure of a ceramic coating according to the application;

[0023] Fig. 3(a) is a cross-sectional SEM morphology diagram of a TiBN coating prepared in Comparative Example 1;

[0024] Fig. 3(b) is a cross-sectional SEM morphology diagram of an AlCrSiTiBN oxidation-resistant coating prepared in Embodiment 1;

[0025] Fig. 4(a) is a cross-sectional SEM morphology diagram of the TiBN coating prepared in Comparative Example 1 after oxidation at 400 DEG C for 10 h;

[0026] Fig. 4(b) is a cross-sectional SEM morphology diagram of the AlCrSiTiBN oxidation-resistant coating prepared in Embodiment 1 after oxidation at 400 DEG C for 10 h;

[0027] Figure 5 Figure 4 is a contrastive diagram of the thickness of the oxide film generated by oxidizing the coating prepared under different preparation conditions at 800℃ for 3h;

[0028] Figure 6(a) is a cross-sectional SEM morphology diagram of the TiBN coating prepared in Comparative Example 1 after oxidation at 800℃ for 3h;

[0029] Figure 6(b) is a cross-sectional SEM morphology diagram of the AlCrSiTiBN oxidation-resistant coating prepared in Example 1 after oxidation at 800℃ for 3h;

[0030] Figure 7 Figure 5 is a diagram of the mechanical properties of the AlCrSiTiBN oxidation-resistant coating prepared in Example 2;

[0031] Wherein: 1-AlCrSi radio frequency target, 2-Ti direct current target, 3-TiB2 direct current target, 4-substrate table, 5-AlCrSiTiBN oxidation-resistant coating, 6-pure Ti transition layer, 7-substrate. DETAILED DESCRIPTION

[0032] The technical solutions in the present application will be described below with reference to the drawings.

[0033] In the embodiments of the present application, the words such as "exemplary", "for example", and the like are used to represent an example, illustration, or description. Any embodiment or design scheme described as "exemplary" in the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. Rather, the word "exemplary" is intended to present the concept in a specific manner. In addition, in the embodiments of the present application, the meaning expressed by "and / or" can be both, or can be one of the two optionally.

[0034] In the embodiments of the present application, "image" and "picture" can be used interchangeably at times, and it should be pointed out that the meanings expressed are consistent when the distinction is not emphasized. "The", "corresponding", and "corresponding" can be used interchangeably at times, and it should be pointed out that the meanings expressed are consistent when the distinction is not emphasized.

[0035] In the embodiments of the present application, sometimes the subscript such as W1 can be mistakenly used in the form of a non-subscript such as W1, and the meanings expressed are consistent when the distinction is not emphasized.

[0036] In order to make the technical problems, technical solutions, and advantages of the present application more clear, the following will be described in detail with reference to the drawings and specific embodiments.

[0037] As Figure 1As shown in the drawings, the internal structure of the chamber of the magnetron sputtering coating instrument used in the application is shown in the drawings, 1 represents an AlCrSi radio frequency target position, 2 represents a Ti direct current target position, 3 represents a TiB2 target direct current target position, and 4 represents a substrate table which can adjust the rotating speed. By using the magnetron sputtering coating instrument, a pure Ti transition layer is first coated on the substrate, and then an AlCrSiTiBN layer is coated.

[0038] The ceramic coating structure prepared by the application is shown in the drawings. Figure 2 As shown in the drawings, 5 represents the AlCrSiTiBN oxidation-resistant coating deposited on the top layer, 7 represents the substrate, and 6 represents the transition layer between the AlCrSiTiBN oxidation-resistant coating 5 and the substrate 7, wherein the transition layer 6 is a pure Ti coating with a thickness of 80-100 nm.

[0039] Example 1

[0040] An AlCrSiTiBN oxidation-resistant coating is prepared on an Al2O3 substrate by using the preparation process designed in the application.

[0041] The atomic ratio of the AlCrSi target is 1:1:1, the AlCrSi target is placed in the radio frequency target position, the Ti target and the TiB2 target are placed in the direct current target position, and the purity of the Ti target and the TiB2 target is 99.99%.

[0042] First, the substrate is polished, then ultrasonic cleaning is performed with acetone, alcohol and deionized water for 10 minutes, and then the substrate is dried and fixed on the substrate table and placed in the coating instrument chamber.

[0043] The chamber is vacuumized to a vacuum degree of 1.8×10 -3 Pa, then the chamber is heated to a deposition temperature of 400℃, inert gas Ar is introduced to adjust the chamber pressure to 1 Pa, the bias voltage of the substrate table is set to -950V, and etching is performed for 10-20 minutes; in this step, the substrate is cleaned by biasing the inert gas.

[0044] The Ti target power is controlled at 450W, the flow of inert gas Ar is adjusted to stabilize the chamber pressure at 0.18-0.21 Pa, and a 80-100 nm thick pure Ti transition layer is sputtered on the surface of the substrate.

[0045] Further, inert gas is introduced and the N2 flow controller switch is opened, 10 sccm of N2 and 30 sccm of Ar are introduced to control the chamber pressure to be 0.18-0.21 Pa, the bias voltage of the substrate table is set to -110V, the rotating speed is 23 rpm, the power of the AlCrSi target material is controlled at 200W, the power of the TiB2 target material is 80W, and an AlCrSiTiBN oxidation-resistant coating is deposited on the pure Ti transition layer at a deposition temperature for 3 hours.

[0046] Example 2

[0047] The difference from Example 1 is that the substrate is single crystal Si.

[0048] Comparative Example 1

[0049] The Al2O3 wafer is used as the substrate, the substrate pretreatment and ion etching process refer to Example 1, and the difference from Example 1 is that only the Ti target and the TiB2 target are used during the coating deposition. The coating deposition process of the comparative example is that after ion etching for 10 min, the cavity pressure is controlled to be 0.21 Pa, the bias voltage is set to be -110 V, the substrate table rotation speed is 23 rpm, the Ti target power is set to be 450 W, the TiB2 target power is set to be 80 W, and the deposition is performed for 2-3 h.

[0050] Comparative Example 2

[0051] The difference from Comparative Example 1 is that the substrate is single crystal Si.

[0052] Comparative Example 3

[0053] The Al2O3 wafer is used as the substrate, and the AlCrSiTiBN oxidation-resistant coating is prepared by using the preparation process designed in the application. The Al2O3 wafer is used as the substrate, the substrate pretreatment and ion etching process refer to Example 1, and the difference from Example 1 is that the AlCrSi target power is controlled to be 160 W during the coating deposition. The coating deposition process of the comparative example is that after ion etching for 10 min, the cavity pressure is controlled to be 0.21 Pa, the bias voltage is set to be -110 V, the substrate table rotation speed is 23 rpm, the Ti target power is set to be 450 W, the TiB2 target power is set to be 80 W, and the AlCrSi target power is set to be 160 W, and the deposition is performed for 3 h.

[0054] Comparative Example 4

[0055] The Al2O3 wafer is used as the substrate, and the AlCrSiTiBN oxidation-resistant coating is prepared by using the preparation process designed in the application. The Al2O3 wafer is used as the substrate, the substrate pretreatment and ion etching process refer to Example 1, and the difference from Example 1 is that the AlCrSi target power is controlled to be 240 W during the coating deposition. The coating deposition process of the comparative example is that after ion etching for 10 min, the cavity pressure is controlled to be 0.21 Pa, the bias voltage is set to be -110 V, the substrate table rotation speed is 23 rpm, the Ti target power is set to be 450 W, the TiB2 target power is set to be 80 W, and the AlCrSi target power is set to be 240 W, and the deposition is performed for 3 h. The cross-sectional morphology of the coating and the oxidation layer of the samples prepared in the examples and the comparative examples are observed and analyzed by using a scanning electron microscope; the oxidation experiments of the coating on the Al2O3 substrate are performed at 400 ℃ for 10 h and at 800 ℃ for 3 h by using a muffle furnace; and the hardness of the coating on the Si substrate is determined by using a nanoindentation.

[0056] Figure 3(a) is a cross-sectional SEM morphology diagram of the TiBN coating of Comparative Example 1; Figure 3(b) is a cross-sectional SEM morphology diagram of the AlCrSiTiBN oxidation-resistant coating prepared in Example 1. As can be seen from Figure 3(a), the TiBN coating has a columnar crystal structure, which provides a channel for the diffusion of oxygen along the grain boundaries. As can be seen from Figure 3(b), after the incorporation of AlCrSi elements, the columnar crystal structure of the coating disappears, and becomes more dense and uniform, and the coating thickness is relatively thicker after the same deposition time, and is well combined with the substrate.

[0057] Figure 4(a) is a cross-sectional SEM morphology diagram of the TiBN coating prepared in Comparative Example 1 after oxidation at 400℃ for 10h; Figure 4(b) is a cross-sectional SEM morphology diagram of the AlCrSiTiBN oxidation-resistant coating prepared in Example 1 after oxidation at 400℃ for 10h. As can be seen from Figures 4(a) and 4(b), under the same conditions, the AlCrSiTiBN oxidation-resistant coating is almost not oxidized, while the TiBN coating generates an oxidation layer of about 60nm.

[0058] Figure 5 According to the statistics of the oxidation films generated by Comparative Examples 1, 3 and 4 after oxidation at 800℃ for 3h, it can be seen that with the increase of the power of the AlCrSi target, the thickness of the oxidation layer shows a trend of first decreasing and then increasing, and the coating oxidation film is thickest at a power of 200W, representing the best oxidation resistance.

[0059] Figure 6(a) is a cross-sectional SEM morphology diagram of the TiBN coating prepared in Comparative Example 1 after oxidation at 800℃ for 3h; Figure 6(b) is a cross-sectional SEM morphology diagram of the AlCrSiTiBN oxidation-resistant coating prepared in Example 1 after oxidation at 800℃ for 3h. As can be seen from Figures 6(a) and 6(b), under the same conditions, the thickness of the oxidation film generated by the AlCrSiTiBN oxidation-resistant coating is about 210nm, while the TiBN is completely oxidized to form a loose and porous TiO2. The AlCrSiTiBN oxidation-resistant coating prepared in the present application shows more excellent oxidation resistance, mainly because the addition of Al and Cr elements makes the coating form a dense Al2O3 and Cr2O3 oxidation layer, which hinders the further diffusion of O along the grain boundaries, and the addition of Si element refines the crystal grains, forming an amorphous wrapping nanocrystalline structure which helps to hinder the diffusion of oxygen along the grain boundaries and is also beneficial to the maintenance of the mechanical properties of the coating. When the power of the AlCrSi target is 200W, the composition of the coating is Al 6.4 Cr 6.8 Si 4.5The oxidation resistance of the TiBN coating is optimal, the Cr addition inhibits the transformation of metastable TiO2 to stable state during the oxidation process, thereby improving the oxidation resistance. The incorporation of Si hinders the growth of TiN columnar crystals, refines the film layer structure, and improves the hardness and oxidation resistance. However, when the Si content is further increased, the excessive amorphous phase formed will cause the hardness of the coating to decrease. The maximum Al content in the coating is 0.64-0.7, and when the content is less than the value, the coating is a face-centered cubic structure, the grain size of the coating is refined with the increase of the Al content, and the hardness and oxidation resistance are improved. When the content is greater than 0.7, the cubic AlN phase is transformed into a hexagonal AlN phase, and the hardness and bonding strength are reduced. The Al content should be increased as much as possible without the presence of h-AlN, and therefore the oxidation resistance of the 200W coating is optimal.

[0060] Figure 7 The mechanical properties of the AlCrSiTiBN oxidation-resistant coating prepared in Example 2 and Comparative Example 2 are shown in the figure. Figure 7 It can be seen that the hardness of the AlCrSiTiBN coating after the incorporation of AlCrSi elements is still 39.39 GPa, and the elastic modulus is 381.26 GPa, indicating that the coating has excellent oxidation resistance and high hardness.

[0061] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for the production of a ceramic coating for the surface of an aircraft engine compressor, characterized in that, The application relates to a method for preparing an AlCrSiTiBN anti-oxidation coating on a substrate. Step S1: polishing the substrate, then cleaning the substrate with organic solvent and deionized water in sequence, fixing the dried substrate on a substrate table, and finally placing the substrate in a chamber of a coating device; Step S2: placing an AlCrSi target, a Ti target and a TiB2 target on target positions respectively; Step S3, vacuumize the chamber to a vacuum degree of 1.8x10 -3 Pa, then warm up the chamber to a deposition temperature of 300-400℃, adjust the chamber pressure to 1 Pa by inputting inert gas, set the bias voltage of the substrate table to -950 V, and etch for 10-20 min. Step S4: controlling the Ti target power to be between 400-480W, adjusting the flow of inert gas Ar to stabilize the chamber pressure at 0.18-0.21Pa, and sputtering a 80-100nm-thick pure Ti transition layer on the substrate surface; Step S5: further introducing inert gas and opening the N2 flow controller switch, controlling the chamber pressure to be 0.18-0.21Pa, setting the bias voltage of the substrate table to be-110V and the rotating speed to be 23rpm, controlling the power of the AlCrSi target to be between 160-240W and the power of the TiB2 target to be between 65-85W, and depositing for 2-3h at a deposition temperature to form an AlCrSiTiBN anti-oxidation coating on the pure Ti transition layer.

2. The method of claim 1, wherein, In step S1, the organic solvent is selected from acetone and alcohol, and the cleaning method is selected from ultrasonic cleaning.

3. The method of claim 1, wherein, In step S1, the substrate is selected from one of single crystal Si, single crystal Al2O3 and 304 stainless steel.

4. The method of claim 1, wherein, In step S2, the AlCrSi target is placed on a radio frequency target position, the chemical composition ratio of Al, Cr and Si in the target is 1:1:1, the Ti target and the TiB2 target are placed on direct current target positions, the purity of the targets reaches 99.99%, and the size of the targets is 76.2*5mm.

5. The method of claim 1, wherein, In step S3, the inert gas is selected from argon.

6. The method of claim 1, wherein, In step S5, Ar and N2 are introduced, the flow ratio is 3:1, the pressure is stabilized at 0.18Pa, the power of the AlCrSi target is controlled to be 200W, the power of the TiB2 target is controlled to be 80W, and the deposition is performed for 3h at a deposition temperature.

7. Ceramic coating produced according to the method of any one of claims 1 to 6, characterized by The AlCrSiTiBN anti-oxidation coating comprises a substrate, a pure Ti transition layer and an AlCrSiTiBN anti-oxidation coating, the ceramic coating can resist oxidation at 800 DEG C and maintain high strength and high toughness.

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