Thermal barrier coating as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of coatings, and particularly discloses a thermal barrier coating and a preparation method and application thereof, the thermal barrier coating comprises a ceramic layer and a modified layer stacked on the ceramic layer; the number of the modified layers is greater than or equal to 2; the preparation material of each modified layer is independently selected from at least one of Ti, Al and Al-X alloy; x in the Al-X alloy is selected from at least one of Ti, La, Ce, Gd, Yb, Lu and Y. According to the thermal barrier coating, the ceramic layer is coated with the modified layer, the bonding strength between the ceramic layer and the modified layer is high and reaches 80 MPa or above, and the thermal barrier coating has excellent CMAS corrosion resistance and scouring resistance, specifically, after 120 times of 1200 DEG C water cold and hot impact experiments, the modified layer is not damaged and is completely compact to form continuous protection on the ceramic layer, and the thermal barrier coating is good in corrosion resistance and corrosion resistance. And the corrosion depth of the coating is shallower when CMAS corrosion is carried out for 30 hours at the temperature of 1200 DEG C.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating, and particularly relates to a thermal barrier coating and a preparation method and application thereof. BACKGROUND

[0002] The thermal barrier coating is a low-thermal-conductivity ceramic material with certain functions, which is compounded on the surface of a high-temperature component in the form of a coating or a film, so as to have the functions of high-temperature resistance, corrosion resistance, wear resistance, heat insulation, etc., and is widely used in the fields of aviation, aerospace, energy, etc. The design and preparation of the thermal barrier coating are indispensable key technologies in the fields of civil industry, etc. Today, the preparation technology of the coating is paid more and more attention, and different preparation technologies directly affect the microstructure of the thermal barrier coating, and further affect the service life of the protected components such as engine turbine blades.

[0003] With the further deepening of the understanding of the failure mechanism of the thermal barrier coating, thermal corrosion has become an important factor for the failure of the thermal barrier coating, and among the thermal corrosion, CMAS (CaO2, MgO, Al2O3, SiO2, etc. are the abbreviation of aluminum silicate salt substances) corrosion is the most serious. CMAS mainly comes from dust, sand, aircraft runway abrasion and engine front stage component spall, etc. When the aircraft engine is in service, CMAS will be sucked into the engine along with the intake inner channel, and after being heated by the high temperature of the compressor and the combustion chamber, it becomes a molten body and is adsorbed on the surface of the ceramic layer and has a thermal chemical reaction with the coating, and then the coating fails prematurely.

[0004] When CMAS penetrates into the pores of the YSZ coating, it will destroy the structure of the ceramic layer, and then have a great influence on the mechanical properties. The thermal mechanical effect of CMAS on the thermal barrier coating is not single. Firstly, after CMAS is melted, it adheres, penetrates and erodes the YSZ layer, compacts the ceramic layer and cools the mutual solution, and generates a large internal stress to cause the delamination and spalling of the thermal barrier coating, etc. Secondly, the thermal chemical action is based on the absorption of Y of YSZ, the crystal type transformation of zirconia, and then the mechanical action of volume change and internal stress, etc.

[0005] With the service of the thermal barrier coating, the surface damage of the thermal barrier coating caused by factors such as erosion, thermal-mechanical-chemical coupling corrosion often becomes the starting point of the cracking or peeling failure of the coating, which is because the surface damage of the thermal barrier coating easily becomes the starting point of the penetration path of the corrosive substances, thereby causing the premature failure of the thermal barrier coating, and greatly reducing the service life and reliability of the aircraft engine. SUMMARY

[0006] In order to overcome at least one technical problem existing in the prior art, one of the purposes of the present application is to provide a thermal barrier coating.

[0007] The second purpose of the present application is to provide a preparation method of the thermal barrier coating.

[0008] The third object of the present application is to provide a product containing the thermal barrier coating.

[0009] To achieve the above object, the technical solution adopted by the present application is: The first aspect of the present application provides a thermal barrier coating, comprising a ceramic layer and a modified layer stacked on the ceramic layer; the number of the modified layer is ≥2; the preparation material of each modified layer is independently selected from at least one of Ti, Al, Al-X alloy; X in the Al-X alloy is selected from at least one of Ti, lanthanum (La), cerium (Ce), gadolinium (Gd), ytterbium (Yb), lutetium (Lu), yttrium (Y).

[0010] In some embodiments of the present application, the number of the modified layer is 2-10 layers; in some embodiments of the present application, the number of the modified layer is any one of 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, 7 layers, 8 layers, 9 layers, 10 layers or a range value formed by any two of them.

[0011] In some embodiments of the present application, the material of the ceramic layer comprises yttria-stabilized zirconia.

[0012] In some embodiments of the present application, the ceramic layer contains 5-10% yttria by mass percentage; in some embodiments of the present application, the mass percentage of yttria in the ceramic layer is any one of 5%, 6%, 7%, 8%, 9%, 10% or a range value formed by any two of them.

[0013] In some embodiments of the present application, the thickness of each modified layer is 1-50 μm; in some embodiments of the present application, the thickness of each modified layer is any one of 1 μm, 3 μm, 5 μm, 7 μm, 10 μm, 13 μm, 15 μm, 17 μm, 20 μm, 23 μm, 25 μm, 27 μm, 30 μm, 33 μm, 35 μm, 37 μm, 40 μm, 43 μm, 45 μm, 47 μm, 50 μm or a range value formed by any two of them.

[0014] In some embodiments of the present application, the Al-X alloy contains 5-50% X by mass percentage; in some embodiments of the present application, the mass percentage of X in the Al-X alloy is any one of 5%, 7%, 10%, 13%, 15%, 17%, 20%, 23%, 25%, 27%, 30%, 33%, 35%, 37%, 40%, 43%, 45%, 47%, 50% or a range value formed by any two of them.

[0015] In some embodiments of the present application, the modified layer contains at least one component selected from t'-ZrO2, Al(TiO) x , and α-Al2O3. The α-Al2O3 with high strength and excellent thermal stability in the modified layer significantly improves the erosion and corrosion resistance of the thermal barrier coating, wherein t'-ZrO2 refers to tetragonal zirconia, and Al(TiO) x refers to a compound formed by titanium oxide groups and Al, wherein (TiO) x is a titanium oxide group, for example, Al2Ti7O 15 .

[0016] In some embodiments of the present application, the modified layer has a scale-like bionic structure.

[0017] The second aspect of the present application provides a method for preparing the thermal barrier coating of the first aspect of the present application, comprising the following steps: depositing at least two layers of the modified layer on the ceramic layer, and then heating to react, thereby obtaining the thermal barrier coating.

[0018] The present application uses in-situ reaction to form an in-situ reaction functional layer (i.e. the modified layer) on the surface of the ceramic layer. Since the modified layer is generated by in-situ reaction, it will not fall off and fail due to the accumulation of internal stress caused by the interface, and since the modified layer is chemically combined with the surface of the ceramic layer, the overall bonding performance of the coating will not be reduced, thereby making the bonding strength of the ceramic layer and the modified layer greater than 80 MPa, which is suitable for the thermal protection requirements of key hot end components such as turbine blades of aero-engine and various combustion engines in extreme service environments. In addition, the preparation method of the present application is simple, and different modified layers can be prepared in the same furnace.

[0019] In some embodiments of the present application, the ceramic layer is prepared by any one method selected from high-velocity oxy-fuel spraying (HVOF), atmospheric plasma spraying (APS), low-pressure plasma spraying (VPS), electron beam-physical vapor deposition (EB-PVD), and plasma spraying-physical vapor deposition (PS-PVD).

[0020] In some embodiments of the present application, the ceramic layer needs to be cleaned before use; in some embodiments of the present application, the ceramic layer is brushed with ethanol or acetone and then dried with nitrogen before use.

[0021] In some embodiments of the present application, the reaction is carried out in a vacuum heat treatment furnace.

[0022] In some embodiments of the present application, the step of depositing at least two layers of the modified layer on the ceramic layer is: sequentially depositing an Al layer and an Al-Ti alloy layer on the ceramic layer.

[0023] In some embodiments of the present application, the temperature of the reaction is 400-1100℃; in some embodiments of the present application, the temperature of the reaction is any one of 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃ or a range formed by any two of them.

[0024] The modified layer in the present application is reacted under vacuum to generate Al(TiO) x with high corrosion resistance, α-Al2O3 with excellent thermal stability, so that the surface of the ceramic layer is completely coated and a modified layer with self-repairing function is formed, and in the service process, Al(TiO) x components and CMAS (CaO2, MgO, Al2O3, SiO2) are completely non-infiltrated, realizing the function of resisting CMAS corrosion; the anisotropic thermal expansion coefficient of Al(TiO) x components realizes the densification and self-repairing of the coating surface in the service process; the α-Al2O3 component with high strength and thermal stability improves the erosion resistance of the thermal barrier coating, significantly enhances the CMAS corrosion resistance and erosion resistance of the thermal barrier coating, and significantly improves the service life of the coating. The preparation method in the present application can improve the coating property of the YSZ columnar crystal surface in the ceramic layer. (TiO) x in Al(TiO) x refers to a titanium-oxygen group, for example, Al2Ti7O 15 .

[0025] In some embodiments of the present application, the reaction time is 1-10h; in some embodiments of the present application, the reaction time is any one of 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h or a range formed by any two of them.

[0026] In some embodiments of the present application, the reaction is carried out under vacuum or protective atmosphere.

[0027] In some embodiments of the present application, the deposition is carried out by vacuum arc ion plating method or magnetron sputtering method.

[0028] In some embodiments of the present application, the vacuum arc ion plating method is as follows: the preparation material of the modified layer is used as the target material, and the deposition is carried out at a temperature of 150-350℃, a bias voltage of 80-180V, a current of 50-150A, and a flow rate of the protective gas of 18-28sccm.

[0029] In some embodiments of the present application, the temperature in the vacuum arc ion plating method is any one of 150℃, 160℃, 180℃, 200℃, 220℃, 240℃, 250℃, 260℃, 280℃, 300℃, 320℃, 340℃, 350℃, or a range formed by any two of them.

[0030] In some embodiments of the present application, the bias voltage in the vacuum arc ion plating method is any one of 80V, 90V, 100V, 110V, 120V, 130V, 140V, 150V, 160V, 170V, 180V, or a range formed by any two of them.

[0031] In some embodiments of the present application, the current in the vacuum arc ion plating method is any one of 50A, 60A, 70A, 80A, 90A, 100A, 110A, 120A, 130A, 140A, 150A, or a range formed by any two of them.

[0032] In some embodiments of the present application, the flow rate of the protective gas in the vacuum arc ion plating method is any one of 18sccm, 20sccm, 22sccm, 24sccm, 26sccm, 28sccm, or a range formed by any two of them.

[0033] In some embodiments of the present application, the magnetron sputtering method is performed at a temperature of 150-350℃, a bias voltage of 60-140V, and a flow rate of the protective gas of 140-180sccm, using the material for preparing the modification layer as the target material.

[0034] In some embodiments of the present application, the temperature in the magnetron sputtering method is any one of 150℃, 160℃, 180℃, 200℃, 220℃, 240℃, 250℃, 260℃, 280℃, 300℃, 320℃, 340℃, 350℃, or a range formed by any two of them.

[0035] In some embodiments of the present application, the bias voltage in the magnetron sputtering method is any one of 60V, 70V, 80V, 90V, 100V, 110V, 120V, 130V, 140V, or a range formed by any two of them.

[0036] In some embodiments of the present application, the flow rate of the protective gas in the magnetron sputtering method is any one of 140sccm, 150sccm, 160sccm, 170sccm, 180sccm, or a range formed by any two of them.

[0037] In some embodiments of the present application, the target material comprises at least one of a Ti target, an Al target, and an Al-X alloy target.

[0038] In some embodiments of the present application, the purity of the target material is ≥ 99.99%.

[0039] A third aspect of the present application provides a product comprising the thermal barrier coating of the first aspect of the present application; the product comprising an engine, an engine blade, an engine floating pad, a heat insulation pad, or a gas turbine.

[0040] In some embodiments of the present application, the engine comprises an airplane engine, a car engine, a ship engine, a train engine, or a gas engine.

[0041] The present application has the following beneficial effects: the thermal barrier coating in the present application is coated with a ceramic layer through a modification layer, the bonding strength between the ceramic layer and the modification layer is high, reaching more than 80 MPa, and has excellent CMAS corrosion resistance and erosion resistance; specifically, after 120 times of 1200℃ water cooling thermal shock experiments, the modification layer is not damaged and has completely densified to form continuous protection for the ceramic layer, and the corrosion depth of the coating is shallow after 30 hours of CMAS corrosion at 1200℃.

[0042] In addition, the modification layer in the present application contains Al(TiO) x and α-Al2O3 with excellent thermal stability, so that the surface of the ceramic layer is completely coated and forms a modification layer with self-repairing function; in the service process, Al(TiO) x components are completely non-infiltrated with CMAS (CaO2, MgO, Al2O3, SiO2), realizing the function of CMAS corrosion resistance; Al(TiO) x components realize the densification and self-repairing of the coating surface in the service process; α-Al2O3 components with high strength and thermal stability improve the erosion resistance of the thermal barrier coating, significantly enhancing the CMAS corrosion resistance and erosion resistance of the thermal barrier coating, and significantly improving the service life of the coating. The preparation method in the present application can improve the coating of the YSZ columnar crystal surface in the ceramic layer. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 SEM image of the self-repairing thermal barrier coating in Example 1.

[0044] Figure 2 XRD image of the self-repairing thermal barrier coating in Example 1.

[0045] Figure 3 Actual image of the thermal barrier coating in Example 1 after 120 times of 1200℃ water cooling thermal shock experiments.

[0046] Figure 4 The surface morphology test chart of the thermal barrier coating in Example 1 before and after 120 times of 1200℃ water-cooling thermal shock experiment.

[0047] Figure 5 The cross-section morphology test chart of the thermal barrier coating in Example 1 before and after 120 times of 1200℃ water-cooling thermal shock experiment.

[0048] Figure 6 The surface morphology test chart of the thermal barrier coating in Comparative Example 1 before and after 10 times of 1200℃ water-cooling thermal shock experiment.

[0049] Figure 7 The surface morphology test chart of the thermal barrier coating prepared in Comparative Example 2.

[0050] Figure 8 The surface morphology chart of Comparative Example 2 after 50 times of water-cooling thermal shock.

[0051] Figure 9 The test chart of the thermal barrier coating in Example 1 and the YSZ thermal barrier coating in Step (1) of Example 1 after CMAS corrosion for 30 hours. DETAILED DESCRIPTION

[0052] The specific implementation of the present application is further described in detail below in combination with the drawings and examples, but the implementation and protection of the present application are not limited thereto. It should be noted that if the following processes are not specifically described in detail, they can be implemented or understood by those skilled in the art with reference to the prior art. If the reagents or instruments used are not marked with the manufacturer, they are conventional products that can be purchased on the market.

[0053] Example 1 The present example provides a preparation method of a self-repairing thermal barrier coating with scale armor biomimetic structure, comprising the following steps: Step one: vacuum coating of the modified layer by magnetron sputtering (1) The surface of the YSZ thermal barrier coating (i.e. ceramic layer) obtained by the plasma spraying-physical vapor deposition (PS-PVD) method is cleaned, and after being brushed with ethanol or acetone, it is dried with nitrogen.

[0054] (2) Different targets required for coating are installed in the magnetron sputtering equipment, a pure Ti target is installed in column A, and a pure aluminum target is installed in column C. The parameters are set as follows: temperature 350℃, vacuum degree 5×10 -2 Pa, start heating, vacuumize, then pass argon and open the bias, set the bias to 500V, adjust the magnetic field intensity parameters to 8.0V, 8.3Hz, and perform target annealing.

[0055] (3) Put the surface cleaned coating sample (i.e. the sample with YSZ thermal barrier coating in step (1)) into the magnetron sputtering device, vacuumize, and set the parameters: 300℃, vacuum degree 5x10 -3 Pa, rotation speed of the rotating disc 5.0 rpm, start heating, vacuumize, then pass argon gas, the flow rate of the argon gas is 150sccm, first apply bias point target to the A target, set the voltage to 70V, and the film plating time is 100min.

[0056] (4) Apply bias point target to the C target, set the voltage to 70V, the rotation speed of the rotating disc is 5.0 rpm, and the film plating time is 300min.

[0057] (5) After the film plating is completed, open the door to take out the sample after the pressure is balanced.

[0058] Step two: vacuum heat treatment of the modified layer Put the sample prepared in step one into a vacuum heat treatment furnace, and set the heat treatment curve: the vacuum degree is lower than 2.0x10 - 2 Pa, and the temperature is raised to 1000℃ within 360min and kept for 120min, thereby obtaining the self-repairing thermal barrier coating with the scale-like bionic structure in this example. The modified layer exists in situ reaction and infiltration process during the heat treatment, and the thickness of the modified layer is 10-20 microns.

[0059] Comparative example 1 This example provides a preparation method of a thermal barrier coating, which comprises the following steps: Step one: vacuum film plating of the modified layer by magnetron sputtering (1) Clean the surface of the YSZ thermal barrier coating obtained by using PS-PVD spraying, brush wash with ethanol or acetone, and then dry with nitrogen.

[0060] (2) Install different targets required for film plating in the magnetron sputtering device, and install a pure aluminum target in the A column. Set the parameters: temperature 350℃, vacuum degree 5x10 -2 Pa, start heating, vacuumize, pass argon gas and open the bias, set the bias to 500V, adjust the magnetic field intensity parameters to 8.0V and 8.3Hz, and perform target annealing.

[0061] (3) Put the surface cleaned coating sample (i.e. the sample with YSZ thermal barrier coating in step (1)) into the magnetron sputtering device, vacuumize, and set the parameters: 300℃, vacuum degree 5x10 -3 Pa, rotation speed of the rotating disc 5.0 rpm, start heating, vacuumize, pass argon gas, the flow rate of the argon gas is 150sccm, first apply bias point target to the A target, set the voltage to 70V, and the film plating time is 100min.

[0062] (4) Apply a bias voltage to target A, set the voltage to 70V, the turntable speed to 5.0rpm, and the coating time to 300min.

[0063] (5) After the coating is completed, release the gas until the pressure is balanced, then open the door and take out the sample.

[0064] Step 2: Vacuum heat treatment of the modified layer The sample obtained in step one is placed in a vacuum heat treatment furnace, and the heat treatment curve is set as follows: the vacuum degree is below 2.0 × 10⁻⁶. - 2 The thermal barrier coating in this example is obtained by heating to 1000℃ within 360 min and holding at that temperature for 120 min under Pa conditions. The thickness of the coating is 10~20 micrometers.

[0065] Comparative Example 2 This example provides a method for preparing a thermal barrier coating, including the following steps: Step 1: Modified layer magnetron sputtering vacuum coating (1) The YSZ thermal barrier coating (i.e. ceramic layer) obtained by plasma spraying-physical vapor deposition (PS-PVD) is cleaned by brushing with ethanol or acetone and then dried with nitrogen.

[0066] (2) Install different target materials required for coating in the magnetron sputtering equipment. Install a pure Ti target on column A and a pure aluminum target on column C. Set the parameters: temperature 350℃, vacuum degree 5×10 -2 Pa, start heating, evacuate, introduce argon gas and turn on the bias voltage, set the bias voltage to 500V, adjust the magnetic field strength parameters to 8.0V and 8.3Hz, and carry out target refining.

[0067] (3) Place the cleaned coated sample (i.e., the sample with YSZ thermal barrier coating from step (1)) into the magnetron sputtering equipment, evacuate, and set the parameters: 300℃, vacuum degree 5×10 -3 Pa, turntable speed 5.0 rpm, start heating, evacuate, purge argon gas, argon gas flow rate 150 sccm, first apply bias voltage to target A, set voltage 70V, coating time 100min.

[0068] (4) Apply a bias voltage to target C, set the voltage to 70V, the turntable speed to 5.0rpm, and the coating time to 300min.

[0069] (5) After the coating is completed, release the gas until the pressure is balanced, then open the door and take out the sample.

[0070] Step 2: Vacuum heat treatment of the modified layer The sample obtained in step one is placed in a vacuum heat treatment furnace, and the heat treatment curve is set as follows: the vacuum degree is below 2.0 × 10⁻⁶. - 2Pa under 360 min to 600 DEG C and kept for 120 min, and a thermal barrier coating in this example was prepared, with a thickness of 10-20 microns.

[0071] Performance test The surface morphology of the self-repairing thermal barrier coating in Example 1 was tested by a scanning electron microscope, and the specific test results are shown in Figure 1 , wherein, Figure 1 The two small graphs in (a) and (b) are SEM graphs with a scale of 50 microns and 10 microns, respectively. Figure 1 It can be seen that the surface coating with the scale biomimetic structure is formed on the surface of the YSZ thermal barrier coating, the in-situ reaction activity of the modified layer and the YSZ ceramic layer surface is improved, the interface energy caused by the in-situ reaction is reduced, the YSZ ceramic layer surface is completely coated, and the CMAS corrosion resistance of the coating is significantly improved.

[0072] The self-repairing thermal barrier coating in Example 1 was tested by an X-ray diffractometer, and the specific test results are shown in Figure 2 . The self-repairing thermal barrier coating prepared in Example 1 contains t'-ZrO2, alpha-Al2O3, Al2Ti7O 15 three phases.

[0073] The self-repairing thermal barrier coating prepared in Example 1 was placed in room temperature cold water after being kept at 1200 DEG C for 5 minutes, which is recorded as a first water cooling thermal shock, and 120 times of 1200 DEG C water cooling thermal shock was carried out according to the method, and the physical map of the thermal barrier coating after 120 times of 1200 DEG C water cooling thermal shock experiment is shown in Figure 3 , and Figure 3 It can be seen that the surface of the thermal barrier coating in Example 1 is not damaged. The surface morphology of the thermal barrier coating before and after the test was compared and tested by a scanning electron microscope, and the specific test results are shown in Figure 4 , wherein, Figure 4 (a) in the (a) and (b) is the surface morphology graph of the self-repairing thermal barrier coating in Example 1 before the experiment (the scale is 50 microns); Figure 4 (b) in the (b) is the surface morphology graph of the self-repairing thermal barrier coating in Example 1 after 120 times of 1200 DEG C water cooling thermal shock experiment (the scale is 3 microns). It can be seen from Figure 4 that the self-repairing thermal barrier coating in Example 1 after 120 times of 1200 DEG C water cooling thermal shock experiment, the coating surface can be observed significant densification self-repairing phenomenon, indicating that the thermal barrier coating in the present application has excellent self-repairing performance. The coating cross-section morphology of the self-repairing thermal barrier coating in Example 1 before and after 120 times of 1200 DEG C water cooling thermal shock experiment was tested by a scanning electron microscope, and the specific test results are shown in Figure 5 , wherein, Figure 5 (a) in the (a) and (b) is the surface morphology graph of the self-repairing thermal barrier coating in Example 1 before the experiment (the scale is 50 microns);Figure 5 (b) is the coating cross-section morphology of the self-repairing thermal barrier coating in Example 1 after the experiment (the scale is 3 μm). It can be seen from Figure 5 that the self-repairing thermal barrier coating in Example 1 can observe significant densification self-repairing phenomenon at the coating cross-section position after 120 times of 1200℃ water-cooling thermal shock experiment, and the densification self-repairing layer continuously protects the feather column-shaped thermal barrier coating.

[0074] The (Zr, Al) TiOx functional component in the self-repairing modified layer of the present application has anisotropic thermal expansion coefficient, and the characteristic is that the thermal expansion coefficient in the plane direction is ten times of the vertical plane direction. During service, the self-repairing modified layer with the bionic structure of scale armor expands along the plane direction, realizes the growth of the scale armor piece and engagement, and the surface self-repairing functional layer of the YSZ thermal barrier coating continuously densifies. As shown in Figure 5 , the surface morphology of the self-repairing thermal barrier coating after 120 times of 1200℃ water-cooling thermal shock test, the functional layer has been completely densified to form continuous protection for the thermal barrier coating.

[0075] The thermal barrier coating prepared in Comparative Example 1 is placed in room temperature cold water after being kept at 1200℃ for 5 minutes, which is recorded as one time of water-cooling thermal shock, and 10 times of 1200℃ water-cooling thermal shock is carried out according to the method. The surface morphology of the thermal barrier coating before and after the test is compared and tested by scanning electron microscope, and the specific process is shown in Figure 6 , wherein, Figure 6 (a) in the figure is the surface morphology of the thermal barrier coating in Comparative Example 1 before the experiment (the scale is 10 μm); Figure 6 (b) in the figure is the surface morphology of the thermal barrier coating in Comparative Example 1 after the experiment (the scale is 3 μm). It can be seen from Figure 6 that the thermal barrier coating in Comparative Example 1 can observe that the coating surface does not appear densification self-repairing after 10 times of 1200℃ water-cooling thermal shock, and the by-product and surface defects begin to appear. The thermal barrier coating in Comparative Example 1 does not contain Ti element, so the surface cannot form a self-repairing modified layer, and the thermal barrier coating has no densification self-repairing phenomenon during the simulation service, and the coating surface gradually appears damage.

[0076] The surface morphology of the thermal barrier coating prepared in Comparative Example 2 is tested by scanning electron microscope, and the specific process is shown in Figure 7 , wherein, Figure 7 (a) in the figure is the SEM graph with a scale of 30 μm, Figure 7 (b) in the figure is the SEM graph with a scale of 3 μm. It can be seen from Figure 7 that the thermal barrier coating in Comparative Example 2 does not form a self-repairing functional coating with a scale bionic structure because the reaction temperature is low during the preparation of the thermal barrier coating, and the Al with a lower melting point is melted and gathered into small droplets adhered to the surface of the coating in the vacuum environment.

[0077] The thermal barrier coating prepared from Comparative Example 2 was put into room temperature cold water after being kept at 1200℃ for 5 minutes, which was recorded as one water-cooling thermal shock, and 50 times of 1200℃ water-cooling thermal shock was carried out according to the method, and the surface morphology of the coating after testing was shown in Figure 8 ; Comparative Example 2 did not form a modified layer, and its coating was severely damaged and fell off at 1200℃ water-cooling thermal shock, and its effect of resisting 1200℃ water-cooling thermal shock was significantly worse than that of the embodiment of the present application.

[0078] The bonding strength of the thermal barrier coating in Example 1 was measured by using the bonding strength test method for thermal spraying coating in HB5476-1991, and parallel tests were carried out, and the average bonding strength measured was 88.5 MPa.

[0079] The thermal barrier coating prepared in Example 1 and the PS-PVD sprayed YSZ thermal barrier coating without surface modification (i.e. the thermal barrier coating after step one treatment in Example 1) were subjected to CMAS corrosion at 1200℃ for 30 hours, and then the fracture position and corrosion depth of the coating were tested by using a scanning electron microscope, and the specific results were shown in Figure 9 , wherein, Figure 9 , (a), (a1) and (a2) in (a) are respectively the CMAS corrosion test diagram of the PS-PVD sprayed YSZ thermal barrier coating without surface modification, Figure 9 , (a1) and (a2) in (a) are respectively a partial enlarged view and a Si element test diagram of (a); Figure 9 , (b), (b1) and (b2) in (b) are respectively the CMAS corrosion test diagram of the thermal barrier coating prepared in Example 1, Figure 9 , (b1) and (b2) in (b) are respectively a partial enlarged view and a Si element test diagram of (b). Figure 9 It can be seen from the above that the PS-PVD sprayed YSZ feather columnar thermal barrier coating without surface modification is fractured from the lower part of the feather columnar under CMAS corrosion, and the corrosion depth is much deeper than that of the thermal barrier coating in Example 1 of the present application.

[0080] The above embodiments of the present application are described in detail, but the present application is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A thermal barrier coating, characterized in that: It includes a ceramic layer and a modified layer stacked on the ceramic layer; the number of the modified layers is ≥2; the material used to prepare each modified layer is independently selected from at least one of Ti, Al, and Al-X alloys; X in the Al-X alloy is selected from at least one of Ti, La, Ce, Gd, Yb, Lu, and Y.

2. The thermal barrier coating according to claim 1, characterized in that: The ceramic layer is made of yttrium-stabilized zirconium oxide.

3. The thermal barrier coating according to claim 2, characterized in that: The ceramic layer contains 5-10% yttrium oxide by mass.

4. The thermal barrier coating according to claim 1, characterized in that: The thickness of each modified layer is 1~50μm; And / or, the Al-X alloy contains 5 to 50% X by mass.

5. The thermal barrier coating according to any one of claims 1 to 4, characterized in that: The modified layer contains t'-ZrO2 and Al(TiO) x At least one of the components in α-Al2O3.

6. The method for preparing the thermal barrier coating according to any one of claims 1 to 5, characterized in that: Includes the following steps: At least two modified layers are deposited on the ceramic layer, and then heated to react, to obtain the thermal barrier coating.

7. The method for preparing a thermal barrier coating according to claim 6, characterized in that: The reaction has at least one of the following characteristics: (a1) The reaction temperature is 400~1100℃; (a2) The reaction time is 1~10h; (a3) The reaction is carried out under vacuum or a protective atmosphere.

8. The method for preparing a thermal barrier coating according to claim 6, characterized in that: The deposition is performed using a vacuum arc ion plating method or a magnetron sputtering method.

9. The method for preparing a thermal barrier coating according to claim 8, characterized in that: The vacuum arc ion plating method is as follows: the modified layer preparation material is used as the target material, and the plating is carried out at a temperature of 150-350℃, a bias voltage of 80-180V, a current of 50-150A, and a protective gas flow rate of 18-28sccm. or, The magnetron sputtering method is as follows: the modified layer preparation material is used as the target material, and the process is carried out at a temperature of 150-350℃, a bias voltage of 60-140V, and a protective gas flow rate of 140-180sccm.

10. A product, characterized in that: The product includes the thermal barrier coating as described in any one of claims 1 to 5; the product includes an engine, engine blades, engine floating bearings, heat insulation bearings, or gas turbine.

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