A perovskite structure composite coating and a preparation method and application thereof

Abstract

The application discloses a perovskite structure composite coating and a preparation method and application thereof, and the chemical structural formula of the composite coating is Sr 1+ω (Zr x A y B 1‑x‑y )O 3+δ / Re n O m ; A elements and B elements are respectively one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc or Y, and the A elements and the B elements are different; the Re element is Al, La, Zr or Y; the preparation method comprises the following steps: dissolving strontium nitrate, zirconium nitrate or zirconium acetate, a nitrate salt of the A element and a nitrate salt of the B element in water, adding metal oxide particles of the Re element and a dispersing agent, adding ball milling beads for ball milling, and obtaining a spraying raw material; the spraying raw material is sprayed onto a base body by adopting a solution plasma spraying process, so that the composite coating is obtained; and the coating can be used on the surface of a high-temperature alloy material in a high-temperature working environment to play a heat insulation and cooling role.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of perovskite composite coating. Specifically, it is a perovskite structure composite coating and its preparation method and application. BACKGROUND

[0002] In order to continuously improve the development of aero-engine to large thrust-to-weight ratio and high fuel utilization, the inlet temperature of the engine is continuously improved. Public data shows that the turbine inlet temperature of F-119 engine used in F-22 fighter exceeds 1700℃. The surface temperature of high-temperature working components such as blades in the future will reach more than 1300℃, which is much higher than the working temperature (1100℃) that advanced nickel-based high-temperature alloy can withstand. Therefore, thermal barrier coating technology needs to be used to process the surface of the component. This is an effective method to greatly improve the working temperature of the aero-engine.

[0003] The 8YSZ ceramic in service will sinter and volume phase change seriously above 1200℃, resulting in internal stress, cracking and falling off of the coating. Sintering is accompanied by the increase of thermal conductivity, the increase of elastic modulus and the decrease of strain tolerance of the coating. Therefore, it is imperative to develop thermal barrier coating materials with higher service temperature, longer service life and more stable thermophysical properties than 8YSZ.

[0004] SrZrO3 with perovskite structure has a melting point above 2650℃ and low thermal conductivity (2.08W·m -1 ·K -1 ). After doping rare earth elements, the high-temperature polymorphic transformation problem of strontium zirconate is greatly improved. The lower fracture toughness can be improved by forming a composite coating. The preparation technology of thermal barrier coating mainly includes electron beam physical vapor deposition, atmospheric plasma spraying, suspension plasma spraying and solution plasma spraying. The coating prepared by solution plasma spraying has a special interlayer pore structure (IPB). Usually, the solution precursor is one or several solvents such as water or alcohol, and soluble salt is added as the effective component for spraying.

[0005] Patent CN114015963A discloses a method for preparing low-thermal-conductivity thermal barrier layer Sr x (Zr 0.9 A 0.05 B 0.05 )O 1.95+x , wherein A and B are one of lanthanum, cerium, neodymium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium, lutetium and yttrium, A and B are not the same, and 0.8≤x≤1.0. Although the thermal barrier coating has low thermal conductivity and excellent high-temperature phase stability, its hardness and fracture toughness are not high, and when subjected to external force, it is easy to form an expanding crack in the material, which affects its service life. SUMMARY

[0006] For this reason, the technical problem to be solved by the present invention is to provide a perovskite structure composite coating, its preparation method and application, so as to solve the technical problems of the existing low thermal conductivity thermal barrier coating with unsatisfactory hardness and fracture toughness.

[0007] To solve the above technical problems, the present invention provides the following technical solutions:

[0008] A perovskite structure composite coating with a chemical structural formula of Sr 1+ω (Zr x A y B 1-x-y )O 3+δ / Re n O m ; Element A and element B are respectively one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc or Y, and element A and element B are different; Element Re is Al, La, Zr or Y.

[0009] For the above perovskite structure composite coating, -0.2 ≤ ω ≤ 0.2, 0.6 ≤ x < 1, 0 < y ≤ 0.4, -0.2 ≤ δ ≤ 0.2, 0 < n ≤ 2, 0 < m ≤ 4, and both n and m are integers.

[0010] The preparation method of the above perovskite structure composite coating includes the following steps:

[0011] Step (1), adding strontium nitrate, zirconium nitrate or zirconium acetate, nitrate of element A and nitrate of element B into water and stirring to dissolve, obtaining a mixed system A;

[0012] Step (2), adding metal oxide particles of element Re into the mixed system A, stirring and mixing evenly, then adding a dispersant, and continuing to stir and mix evenly to obtain a mixed system B; Adding a dispersant can keep the added metal oxide particles evenly dispersed and suspended in the mixed system B, thereby ensuring the uniformity and stability of the mixed system, being conducive to the formation of a uniformly distributed dispersion phase of the metal oxide particles in the perovskite structure composite coating, and thus preparing a perovskite composite coating with excellent structure and physical properties;

[0013] Step (3), adding ball milling beads to the mixed system B for ball milling, and obtaining a mixed system C after the ball milling ends;

[0014] Step (4), using the solution plasma spraying process to spray the mixed system C as the spraying raw material onto a pretreated metal substrate, and forming a perovskite structure composite coating on the surface of the metal substrate after the spraying ends.

[0015] The SrZrO3 material with a perovskite structure has the characteristics of high melting point and low thermal conductivity. Doping with rare earth elements can solve its high-temperature polymorphic transformation; while Sr 1+ω (Zr x A y B 1-x-y )O 3+δ / Re n O m The composite coating forms uniformly distributed oxide particles in the coating and, by adjusting the spraying parameters, not only improves the hardness of the coating but also enhances the crack propagation force of the coating, and still retains the structure unique to solution plasma spraying.

[0016] In the preparation method of the above perovskite structure composite coating, in step (1), in the mixed system A, the molar ratio of strontium element, zirconium element, A element, and B element is (1 + ω): x: y: (1 - x - y); -0.2 ≤ ω ≤ 0.2, 0.6 ≤ x < 1, 0 < y ≤ 0.4. When the molar ratio of the four is within the above range, the A element and the B element can smoothly replace the zirconium element position to form a single-phase perovskite structure. Otherwise, it may lead to the presence of monoclinic zirconia in the finally prepared composite coating, which affects the coating quality; taking each raw material as Sr 1+ω (Zr x A y B 1-x-y )O 3+δ as the unit, the molar concentration of Sr 1+ω (Zr x A y B 1-x-y )O 3+δ in the mixed system A is 0.8 - 2.0 mol / L.

[0017] In the preparation method of the above perovskite structure composite coating, in step (2), the mass of the metal oxide particles of the Re element is 2 - 40 wt% of the effective mass of Sr 1+ω (Zr x A y B 1-x-y )O 3+δ in the mixed system A, that is, the mass of the metal oxide particles of the Re element is the Sr that can be generated by the raw materials in the mixed system A 1+ω (Zr x A y B 1-x-y )O 3+δ2 to 40 wt% of the theoretical mass, the particle size of the metal oxide particles of the Re element is 0.1 to 1 μm. If the particle size of the metal oxide particles of the Re element exceeds this range, the performance of the finally prepared perovskite structure composite coating will decline; the dispersant is sodium dodecylbenzenesulfonate, sodium polyacrylate or polyacrylic acid; the average relative molecular mass M.W of polyacrylic acid is ~3000; the mass of the dispersant is 0.5 to 5 wt% of the mass of the metal oxide particles of the Re element.

[0018] In the preparation method of the above perovskite structure composite coating, in step (3), the mass of the ball milling beads is 1 to 3 times the mass of the mixed system B; the ball milling speed is 45 to 90 rpm, and the ball milling time is 0.5 to 4 h.

[0019] In the preparation method of the above perovskite structure composite coating, in step (4), the pretreatment method of the metal substrate is: first, use water sandpapers with 50 to 800 meshes to polish the metal substrate in sequence. After the polishing is completed, perform sandblasting treatment on the surface of the metal substrate with 24-mesh white corundum. After the sandblasting treatment is completed, perform ultrasonic cleaning with alcohol having a volume fraction greater than or equal to 99.7%.

[0020] In the preparation method of the above perovskite structure composite coating, in step (4), the process conditions of the solution plasma spraying process are: the current is 260 to 300 A, the total gas flow rate is 260 to 300 slpm, and the ratio of argon, hydrogen and nitrogen is 60:(10 to 20):(20 to 30); the spraying distance is 80 to 100 mm; if the current exceeds the above range, it will cause too much or too little heat energy received by the mixed system C and affect its spraying effect; the gas flow rate can control the movement speed of the particles in the flame on the one hand and is also the heat energy source of the flame on the other hand. Controlling the movement state and melting state of the particles in the flame during the spraying process is the key to depositing the coating; and the type and ratio of the gas will also affect the calorific value and ultimately affect the structure of the coating. In addition, if the spraying distance is too short, the droplet speed is too high, which will cause excessive fragmentation and sputtering, affecting the coating quality. If the spraying distance is too long, the droplet kinetic energy will decrease, and it is not easy to form a uniform coating. By controlling the solution plasma spraying process within the above range, the present invention can effectively control the movement state and melting state of the particles in the mixed system C to reach an ideal situation, so as to deposit a uniform, stable and single-phase perovskite structure coating on the substrate.

[0021] In the preparation method of the above perovskite structure composite coating, in step (1), in the mixed system A, the molar ratio of strontium element, zirconium element, A element and B element is (1 + ω):x:y:(1 - x - y); -0.2 ≤ ω ≤ 0.2, 0.6 ≤ x < 1, 0 < y ≤ 0.4; each raw material is in the form of Sr 1+ω (Zr x A y B1-x-y )O 3+δ For units, the Sr in the mixed system A 1+ω (Zr x A y B 1-x-y )O 3+δ The molar concentration is 0.8–2.0 mol / L;

[0022] In step (2), the mass of the Re metal oxide particles is equal to the mass of Sr in the mixed system A. 1+ω (Zr x A y B 1-x-y )O 3+δ The effective mass is 5-40 wt%; the particle size of the Re element metal oxide particles is 0.1-1 μm; the Re element metal oxide particles can play a toughening role. If the amount is too large, the resulting composite coating will generate large stress due to the large difference in the coefficient of thermal expansion, which will affect the performance of the composite coating. However, if the amount is too small, the ideal toughening effect cannot be achieved. This invention controls the amount of Re element metal oxide particles added and the particle size range of the Re element metal oxide particles, so that the toughening effect of the metal oxide particles can be effectively exerted and the stress generated in the composite coating can be effectively avoided. The dispersant is polyacrylic acid, and the average relative molecular mass of polyacrylic acid is MW-3000; the mass of the Re element metal oxide particles is 0.5-5 wt%.

[0023] In step (3), the mass of the milling beads is 1 to 3 times the mass of the mixture B; the milling speed is 47 to 86 rpm; and the milling time is 0.5 to 4 hours.

[0024] In step (4), the pretreatment method of the metal substrate is as follows: first, use 50-grit to 800-grit wet sandpaper to polish the metal substrate in sequence. After polishing, use 24-grit white corundum to perform sandblasting on the surface of the metal substrate. After sandblasting, use 99.7% alcohol by volume for ultrasonic cleaning.

[0025] The process conditions for solution plasma spraying are as follows: current is 260-300A, total gas flow rate is 260-300 slpm, and the ratio of argon, hydrogen and nitrogen is 60:(10-20):(20-30); spraying distance is 80-100mm.

[0026] The above-mentioned perovskite structure composite coating is applied by spraying the perovskite structure composite coating prepared by the above-mentioned method onto the surface of high-temperature alloy materials in high-temperature working environments to achieve heat insulation and cooling.

[0027] The technical solution of the present invention achieves the following beneficial technical effects:

[0028] 1. The method for preparing the perovskite-structured composite coating of the present invention involves preparing the raw materials for the perovskite-structured composite coating into a solution-based suspension, controlling the types and proportions of each component in the solution-based suspension, and spraying it onto the surface of a substrate material using a solution plasma spraying process. By controlling the parameters of the spraying process, a perovskite-structured composite coating Sr with high hardness and crack propagation force is prepared. 1+ω (Zr x A y B 1-x-y )O 3+δ / Re n O m Furthermore, the coating still exhibits a distinct vertical crack structure, resulting in low thermal conductivity, which allows it to be used for heat insulation and cooling of high-temperature alloy materials in high-temperature working environments.

[0029] 2. The preparation method of the perovskite-structured composite coating of this invention exhibits good stability and high repeatability. By adjusting the types and proportions of raw materials and the spraying process parameters, a composite coating structure with both high hardness and high crack propagation force can be obtained. Furthermore, the coating prepared by this process retains the interlayer porosity structure unique to solution plasma spraying, and vertical cracks and layering still exist in the coating's microstructure. This is highly advantageous for subsequent applications of thermal barrier coatings. Therefore, this invention not only improves the hardness and crack propagation force of the ceramic layer but also enhances the service life of the composite material under high-temperature conditions, extending the coating's lifespan.

[0030] 3. By controlling the type, amount, and particle size range of the added metal oxides, this invention, under the preparation process conditions of the perovskite-structured composite coating, enables the metal oxide particles in the coating to be within the Sr matrix of the composite coating. 1+ω (Zr x A y B 1-x-y )O 3+δ A dispersed phase is formed in the composite coating. When the composite coating is subjected to external force, the dispersed phase can effectively hinder the propagation of cracks inside the composite coating, thereby increasing the fracture toughness of the composite coating material. This results in the final perovskite structure composite coating having both high hardness and high crack propagation capability. Attached Figure Description

[0031] Figure 1 Particle size distribution diagram of the mixed system C during the preparation of the perovskite-structured composite coating in Example 1 of this invention;

[0032] Figure 2 X-ray diffraction pattern of the perovskite-structured composite coating prepared in Example 1 of this invention;

[0033] Figure 3Cross-sectional microstructure of the perovskite-structured composite coating prepared in Example 1 of this invention;

[0034] Figure 4a A cross-sectional view of the perovskite-structured composite coating prepared in Example 1 of this invention;

[0035] Figure 4b The elemental distribution of the perovskite-structured composite coating prepared in Example 1 of this invention;

[0036] Figure 4c Elemental surface scan (Al element) of the perovskite-structured composite coating prepared in Example 1 of this invention; Figure 4d Elemental surface scan (O element) of the perovskite-structured composite coating prepared in Example 1 of this invention; Figure 4e Elemental surface scan (Sr element) of the perovskite-structured composite coating prepared in Example 1 of this invention; Figure 4f Elemental surface scan (Zr element) of the perovskite-structured composite coating prepared in Example 1 of this invention; Figure 4g Elemental surface scan (Yb element) of the perovskite-structured composite coating prepared in Example 1 of this invention;

[0037] Figure 4h Elemental surface scan (Gd element) of the perovskite-structured composite coating prepared in Example 1 of this invention;

[0038] Figure 5 Hardness and crack propagation force diagrams of the perovskite-structured composite coatings prepared in Examples 1-3 of this invention. Detailed Implementation

[0039] Example 1

[0040] The preparation method of the perovskite structure composite coating in this embodiment includes the following steps:

[0041] Step (1): Strontium nitrate, zirconium acetate, ytterbium nitrate, and gadolinium nitrate are prepared in a molar ratio of Sr, Zr, Yb, and Gd of 1:0.9:0.05:0.05 and added to water to dissolve, resulting in mixed system A. The raw materials are added in the form of Sr... 1+ω (Zr x A y B 1-x-y )O 3+δ For units, the Sr in the mixed system A 1+ω (Zr x A y B 1-x-y )O 3+δ The molar concentration of the substance is 1.4 mol / L; through comparative experiments, zirconium acetate, compared with zirconium nitrate, exhibits staged heat release at high temperatures, which is more advantageous for thermal spraying.

[0042] Step (2): Add alumina particles with a particle size of 0.1–1 μm to the mixture A. The mass of the alumina particles is equal to the mass of Sr in the mixture A. 1+ω (Zr x A y B 1-x-y )O 3+δ Add 5 wt% of the effective mass; after stirring and mixing evenly, add polyacrylic acid with an average relative molecular mass of MW~3000 as a dispersant, the mass of the dispersant being 2 wt% of the mass of the alumina particles; continue stirring and mixing evenly to obtain mixed system B;

[0043] Step (3): Add grinding balls to mixture B and ball mill. The mass ratio of the grinding balls to the mass of mixture B is 1:1 (the grinding ball ratio itself is φ1:φ3:φ5=6:3:1). The ball milling speed of the horizontal ball mill is 85 rpm, and the ball milling time is 2 hours. After ball milling, mixture C is obtained. The median particle size of the particles in mixture C is 2.9 μm, and the particle size distribution is uniform (see...). Figure 1 );

[0044] Step (4): The mixed system C is sprayed onto the pretreated metal substrate using a solution plasma spraying process. Specifically: the metal substrate is first polished with 60-800 grit wet sandpaper to make the surface of the metal substrate smooth; after polishing, the surface of the metal substrate is sandblasted with 24-grit white corundum; after sandblasting, the surface of the metal substrate is ultrasonically cleaned with 99.7% alcohol by volume. The pretreated metal substrate is placed on a specific fixture, and the solution plasma spraying process is set as follows: current 300A, total gas flow rate 260slpm, where Ar:H2:N2=60:10:30 (flow rate ratio), and spraying distance 80mm; after spraying, a perovskite composite coating is formed on the surface of the metal substrate, the chemical formula of which is Sr(Zr) 0.9 Yb 0.05 Gd 0.05 )O 2.95 / Al2O3.

[0045] The method in this embodiment achieves a single-pass deposition efficiency of 18.8 μm for the perovskite-structured composite coating, as shown in the XRD diffraction analysis results. Figure 2 As shown, its scanning electron microscope microstructure is as follows: Figure 3 As shown in the figure, the prepared perovskite-structured composite coating still exhibits obvious vertical cracks and a clear IPB structure. Figures 4a to 4hX-ray energy dispersive spectroscopy (EDS) analysis showed that alumina particles were uniformly distributed in the coating, and the elemental content ratios were almost identical to the set values. These results indicate that the alumina particles in the perovskite-structured composite coating prepared in this embodiment are uniformly dispersed within the coating, and the preparation of this composite coating was successful.

[0046] Testing showed that the hardness and crack propagation force of the perovskite-structured composite coating prepared in this embodiment, in the sprayed state, were 9.283 GPa and 10.4 J / m, respectively. 2 .

[0047] Example 2

[0048] The only difference between this embodiment and Embodiment 1 is that in step (4):

[0049] The process conditions for solution plasma spraying are as follows: current 300A, total gas flow rate 260slpm, Ar:H2:N2 = 60:10:30 (flow rate ratio), and spraying distance 90mm.

[0050] The method in this embodiment achieves a single-pass deposition efficiency of 13.5 μm for the perovskite-structured composite coating, and the prepared Sr(Zr) coating... 0.9 Yb 0.05 Gd 0.05 )O 2.95 In the Al2O3 perovskite composite coating, alumina particles are uniformly distributed throughout the coating, and the coating's unique interlayer porosity (IPB structure) is clearly visible. Testing revealed that the composite coating exhibits good hardness and crack propagation resistance. Figure 5 As shown, the values ​​are 7.357 GPa and 12.97 J / m, respectively. 2 .

[0051] Example 3

[0052] The only difference between this embodiment and Embodiment 1 is that in step (4):

[0053] Process conditions for solution plasma spraying: current 300A, total gas flow rate 260slpm, Ar:H2:N2 = 60:10:30 (flow rate ratio), spraying distance 100mm.

[0054] The method in this embodiment achieves a single-pass deposition efficiency of 8.5 μm for the perovskite-structured composite coating, and the prepared Sr(Zr) coating... 0.9 Yb 0.05 Gd 0.05 )O 2.95 In the Al2O3 perovskite composite coating, alumina particles are uniformly distributed throughout the coating, and the IPB structure is clearly visible. Testing revealed that the composite coating exhibits good hardness and crack propagation strength.Figure 5 As shown, the values ​​are 5.815 GPa and 4.409 J / m, respectively. 2 .

[0055] Example 4

[0056] The preparation method of the perovskite structure composite coating in this embodiment includes the following steps:

[0057] Step (1): Strontium nitrate, zirconium acetate, ytterbium nitrate, and gadolinium nitrate are prepared in a molar ratio of Sr, Zr, Yb, and Gd of 1:0.9:0.05:0.05 and added to water to dissolve, resulting in mixed system A. The raw materials are added in the form of Sr... 1+ω (Zr x A y B 1-x-y )O 3+δ For units, the Sr in the mixed system A 1+ω (Zr x A y B 1-x-y )O 3+δ The molar concentration is 1.4 mol / L;

[0058] Step (2): Add yttrium oxide particles with a particle size of 0.1–1 μm to the mixture A. The mass of the yttrium oxide particles is equal to the mass of Sr in the mixture A. 1+ω (Zr x A y B 1-x-y )O 3+δ Add 5 wt% of the effective mass; after stirring and mixing evenly, add polyacrylic acid with an average relative molecular mass of MW~3000 as a dispersant, the mass of the dispersant being 0.5 wt% of the mass of the yttrium oxide particles; continue stirring and mixing evenly to obtain mixture B;

[0059] Step (3): Add grinding balls to the mixture B and ball mill. The mass ratio of the grinding balls to the mass of the mixture B is 1:1 (the grinding balls themselves are φ1:φ3:φ5=6:3:1). The ball milling speed of the horizontal ball mill is 50 rpm and the ball milling time is 2 hours. After the ball milling is completed, the mixture C is obtained.

[0060] Step (4): The mixed system C is sprayed onto the pretreated metal substrate using a solution plasma spraying process. Specifically: the metal substrate is first polished with 60-800 grit sandpaper to make the surface of the metal substrate smooth; after polishing, the surface of the metal substrate is sandblasted with 24-grit white corundum; after sandblasting, the surface of the metal substrate is ultrasonically cleaned with 99.7% alcohol by volume. The pretreated metal substrate is placed on a specific fixture, and the solution plasma spraying process parameters are set as follows: current 260A, total gas flow rate 260slpm, where Ar:H2:N2 = 60:15:25 (flow rate ratio), and spraying distance 90mm; after spraying, a perovskite composite coating is formed on the surface of the metal substrate, the chemical formula of which is Sr(Zr) 0.9 Yb 0.05 Gd 0.05 )O 2.95 / Y2O3.

[0061] The perovskite-structured composite coating prepared in this embodiment has a thickness of 350 μm, and the yttrium oxide particles are uniformly distributed within the coating. Testing showed that the hardness and crack propagation force of the sprayed perovskite-structured composite coating prepared in this embodiment were 7.216 GPa and 5.627 J / m, respectively. 2 .

[0062] Example 5

[0063] The preparation method of the perovskite structure composite coating in this embodiment includes the following steps:

[0064] Step (1): Strontium nitrate, zirconium acetate, ytterbium nitrate, and gadolinium nitrate were prepared in a molar ratio of Sr:Zr:Yb:Gd of 1.1:0.9:0.05:0.05. These were then added to water and stirred to dissolve, resulting in mixed system A. The raw materials were prepared in the form of Sr... 1+ω (Zr x A y B 1-x-y )O 3+δ For units, the Sr in the mixed system A 1+ω (Zr x A y B 1-x-y )O 3+δ The molar concentration is 1.3 mol / L;

[0065] Step (2): Add alumina particles with a particle size of 0.1–1 μm to the mixture A. The mass of the alumina particles is equal to the mass of Sr in the mixture A. 1+ω (Zr x A y B 1-x-y )O 3+δ10 wt% of the effective mass; after stirring and mixing evenly, add polyacrylic acid with an average relative molecular mass of MW~3000 as a dispersant, the mass of the dispersant being 2 wt% of the mass of the alumina particles; continue stirring and mixing evenly to obtain mixed system B;

[0066] Step (3): Add grinding balls to the mixture B and ball mill. The mass ratio of the grinding balls to the mass of the mixture B is 1:1 (the grinding balls themselves are φ1:φ3:φ5=6:3:1). The ball milling speed of the horizontal ball mill is 60 rpm and the ball milling time is 2 hours. After the ball milling is completed, the mixture C is obtained.

[0067] Step (4): The mixed system C is sprayed onto the pretreated metal substrate using a solution plasma spraying process. Specifically: the metal substrate is first polished with 60-800 grit wet sandpaper to make the surface of the metal substrate smooth; after polishing, the surface of the metal substrate is sandblasted with 24-mesh white corundum; after sandblasting, the surface of the metal substrate is ultrasonically cleaned with 99.7% alcohol by volume. The pretreated metal substrate is placed on a specific fixture, and the solution plasma spraying process is set as follows: current 270A, total gas flow rate 280slpm, where Ar:H2:N2 = 60:15:25 (flow rate ratio), and spraying distance 90mm; after spraying, a perovskite composite coating is formed on the surface of the metal substrate, the chemical formula of which is Sr 1.1 (Zr 0.9 Yb 0.05 Gd 0.05 )O 2.95 / Al2O3.

[0068] The perovskite-structured composite coating prepared in this embodiment has a thickness of 300 μm, and the alumina particles are uniformly distributed within the coating. Testing showed that the hardness and crack propagation force of the sprayed perovskite-structured composite coating prepared in this embodiment were 8.259 GPa and 4.053 J / m, respectively. 2 .

[0069] Example 6

[0070] The preparation method of the perovskite structure composite coating in this embodiment includes the following steps:

[0071] Step (1): Strontium nitrate, zirconium acetate, ytterbium nitrate, and gadolinium nitrate were prepared in a molar ratio of 0.9:0.80:0.05:0.15 and added to water to dissolve, resulting in mixed system A. The raw materials were prepared in the form of Sr, Zr, Yb, and Gd. 1+ω (Zr x A y B 1-x-y )O 3+δFor units, the Sr in the mixed system A 1+ω (Zr x A y B 1-x-y )O 3+δ The molar concentration is 1.5 mol / L;

[0072] Step (2): Add alumina particles with a particle size of 0.1–1 μm to the mixture A. The mass of the alumina particles is equal to the mass of Sr in the mixture A. 1+ω (Zr x A y B 1-x-y )O 3+δ Add 5 wt% of the effective mass; after stirring and mixing evenly, add polyacrylic acid with an average relative molecular mass of MW~3000 as a dispersant, the mass of the dispersant being 2 wt% of the mass of the alumina particles; continue stirring and mixing evenly to obtain mixed system B;

[0073] Step (3): Add grinding balls to the mixture B and ball mill. The mass ratio of the grinding balls to the mass of the mixture B is 1:1 (the grinding balls themselves are φ1:φ3:φ5=6:3:1). The ball milling speed of the horizontal ball mill is 70 rpm and the ball milling time is 2 hours. After the ball milling is completed, the mixture C is obtained.

[0074] Step (4): The mixed system C is sprayed onto the pretreated metal substrate using a solution plasma spraying process. Specifically: the metal substrate is first polished with 60-800 grit sandpaper to make the surface of the metal substrate smooth; after polishing, the surface of the metal substrate is sandblasted with 24-grit white corundum; after sandblasting, the surface of the metal substrate is ultrasonically cleaned with 99.7% alcohol by volume. The pretreated metal substrate is placed on a specific fixture, and the solution plasma spraying process is set as follows: current 260A, total gas flow rate 280slpm, where Ar:H2:N2 = 60:15:25 (flow rate ratio), and spraying distance 90mm; after spraying, a perovskite composite coating is formed on the surface of the metal substrate, the chemical formula of which is Sr 0.9 (Zr 0.80 Yb 0.05 Gd 0.15 )O 2.95 / Al2O3.

[0075] The perovskite-structured composite coating prepared in this embodiment has a thickness of 300 μm, and the alumina particles are uniformly distributed within the coating. Testing showed that the hardness and crack propagation force of the sprayed perovskite-structured composite coating prepared in this embodiment were 8.105 GPa and 9.32 J / m, respectively. 2 .

[0076] Example 7

[0077] The preparation method of the perovskite structure composite coating in this embodiment includes the following steps:

[0078] Step (1): Strontium nitrate, zirconium acetate, ytterbium nitrate, and gadolinium nitrate were prepared in a molar ratio of 0.9:0.80:0.05:0.15 and added to water to dissolve, resulting in mixed system A. The raw materials were prepared in the form of Sr, Zr, Yb, and Gd. 1+ω (Zr x A y B 1-x-y )O 3+δ For units, the Sr in the mixed system A 1+ω (Zr x A y B 1-x-y )O 3+δ The molar concentration is 1.5 mol / L;

[0079] Step (2): Add lanthanum oxide particles with a particle size of 0.1–1 μm to the mixture A. The mass of the lanthanum oxide particles is equal to the mass of Sr in the mixture A. 1+ω (Zr x A y B 1-x-y )O 3+δ Add 5 wt% of the effective mass; after stirring and mixing evenly, add polyacrylic acid with an average relative molecular mass of MW~3000 as a dispersant, the mass of the dispersant being 1 wt% of the mass of the lanthanum oxide particles; continue stirring and mixing evenly to obtain mixed system B;

[0080] Step (3): Add grinding balls to the mixture B and ball mill. The mass ratio of the grinding balls to the mass of the mixture B is 1:1 (the grinding balls themselves are φ1:φ3:φ5=6:3:1). The ball milling speed of the horizontal ball mill is 80 rpm and the ball milling time is 2 hours. After the ball milling is completed, the mixture C is obtained.

[0081] Step (4): The mixed system C is sprayed onto the pretreated metal substrate using a solution plasma spraying process. Specifically: the metal substrate is first polished with 60-800 grit sandpaper to make the surface of the metal substrate smooth; after polishing, the surface of the metal substrate is sandblasted with 24-mesh white corundum; after sandblasting, the surface of the metal substrate is ultrasonically cleaned with 99.7% alcohol by volume. The pretreated metal substrate is placed on a specific fixture, and the solution plasma spraying process is set as follows: current 260A, total gas flow rate 300slpm, where Ar:H2:N2 = 60:17:23 (flow rate ratio), and spraying distance 90mm; after spraying, a perovskite composite coating is formed on the surface of the metal substrate, the chemical formula of which is Sr 0.9 (Zr 0.8 Yb 0.05 Gd 0.15 )O 2.95 / La2O3.

[0082] The perovskite-structured composite coating prepared in this embodiment has a thickness of 300 μm, and the alumina particles are uniformly distributed within the coating. Testing showed that the hardness and crack propagation force of the sprayed perovskite-structured composite coating prepared in this embodiment were 6.524 GPa and 11.62 J / m, respectively. 2 .

[0083] Example 8

[0084] The preparation method of the perovskite structure composite coating in this embodiment includes the following steps:

[0085] Step (1): Strontium nitrate, zirconium acetate, ytterbium nitrate, and gadolinium nitrate were prepared in a molar ratio of 0.9:0.80:0.05:0.15 and added to water to dissolve, resulting in mixed system A. The raw materials were prepared in the form of Sr, Zr, Yb, and Gd. 1+ω (Zr x A y B 1-x-y )O 3+δ For units, the Sr in the mixed system A 1+ω (Zr x A y B 1-x-y )O 3+δ The molar concentration is 1.5 mol / L;

[0086] Step (2): Add zirconium dioxide particles with a particle size of 0.1–1 μm to the mixture A. The mass of the zirconium dioxide particles is equal to the mass of Sr in the mixture A. 1+ω (Zr x A y B 1-x-y )O3+δ 15 wt% of the effective mass; after stirring and mixing evenly, add sodium dodecylbenzenesulfonate as a dispersant, the mass of the dispersant being 1 wt% of the mass of the zirconium dioxide particles; continue stirring and mixing evenly to obtain mixture B;

[0087] Step (3): Add grinding balls to the mixture B and ball mill. The mass ratio of the grinding balls to the mass of the mixture B is 1:1 (the grinding balls themselves are φ1:φ3:φ5=6:3:1). The ball milling speed of the horizontal ball mill is 80 rpm and the ball milling time is 2 hours. After the ball milling is completed, the mixture C is obtained.

[0088] Step (4): The mixed system C is sprayed onto the pretreated metal substrate using a solution plasma spraying process. Specifically: the metal substrate is first polished with 60-800 grit wet sandpaper to make the surface of the metal substrate smooth; after polishing, the surface of the metal substrate is sandblasted with 24-mesh white corundum; after sandblasting, the surface of the metal substrate is ultrasonically cleaned with 99.7% alcohol by volume. The pretreated metal substrate is placed on a specific fixture, and the solution plasma spraying process is set as follows: current 260A, total gas flow rate 300slpm, where Ar:H2:N2 = 60:20:20 (flow rate ratio), and spraying distance 90mm; after spraying, a perovskite composite coating is formed on the surface of the metal substrate, the chemical formula of which is Sr 0.9 (Zr 0.80 Yb 0.05 Gd 0.15 )O 2.95 / ZrO2.

[0089] The perovskite-structured composite coating prepared in this embodiment has a thickness of 300 μm, and the zirconium dioxide particles are uniformly distributed within the coating. Testing showed that the hardness and crack propagation force of the sprayed perovskite-structured composite coating prepared in this embodiment were 10.384 GPa and 13.527 J / m, respectively. 2 .

[0090] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for preparing a perovskite structure composite coating, characterized in that, It comprises the following steps: Step (1), strontium nitrate, zirconium nitrate or zirconium acetate, nitrate of element A and nitrate of element B are added into water and stirred to dissolve, obtaining mixed system A; Step (2), metal oxide particles of element Re are added into mixed system A, and after stirring and mixing, a dispersant is added, and stirring and mixing are continued, obtaining mixed system B; Step (3), ball milling beads are added into mixed system B for ball milling, and after ball milling, mixed system C is obtained; Step (4), mixed system C is used as a spraying raw material to be sprayed onto a pretreated metal substrate by a solution plasma spraying process, and after spraying, a perovskite structure composite coating is formed on the surface of the metal substrate; The chemical structural formula of the perovskite structure composite coating is Sr 1+ω (Zr x A y B 1-x-y )O 3+δ / Re n O m ; the A element and the B element are one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc or Y, and the A element and the B element are different; the Re element is Al, La, Zr or Y; Step (1), in the mixed system A, the amount-of-substance ratio of the four substances of strontium element, zirconium element, element A and element B is (1+ω):x:y:(1-x-y); -0.2≤ω≤0.2, 0.6≤x<1, 0<y≤0.4; each raw material is counted by Sr 1+ω (Zr x A y B 1-x-y )O 3+δ , then the amount-of-substance concentration of Sr 1+ω (Zr x A y B 1-x-y )O 3+δ in the mixed system A is 0.8-2.0 mol / L; 0<n≤2, 0<m≤4, n and m are integers; The mass of the metal oxide particles of the Re element in step (2) is 0.1 to 10 wt% of the mixed system A 1+ω (Zr x A y B 1-x-y )O 3+δ The mass of the metal oxide particles of the Re element is 2 to 40 wt% of the effective mass, and the particle size of the metal oxide particles of the Re element is 0.1 to 1 μm. In step (4), the process conditions of the solution plasma spraying process are: current is 260-300 A, total gas flow is 260-300 slpm, and the ratio of argon, hydrogen and nitrogen is 60: (10-20): (20-30); the spraying distance is 80-100 mm.

2. The method of claim 1, wherein the perovskite composite coating is prepared by a method comprising: In step (2), the dispersant is sodium dodecyl benzene sulfonate, sodium polyacrylate or polyacrylic acid; the average relative molecular mass of polyacrylic acid is M.W~3000; the mass of the dispersant is 0.5-5 wt% of the mass of the metal oxide particles of element Re.

3. The method for preparing the perovskite-structured composite coating according to claim 1, characterized in that, In step (3), the mass of the ball milling beads is 1-3 times the mass of mixed system B; the ball milling speed is 45-90 rpm, and the ball milling time is 0.5-4 h.

4. The method of claim 1, wherein the perovskite composite coating is prepared by a method comprising: In step (4), the pretreatment method of the metal substrate is: first, the metal substrate is polished with 50-800 mesh water sandpaper in sequence, then white corundum with a mesh of 24 is used to perform sand blasting treatment on the surface of the metal substrate, and after the sand blasting treatment, the metal substrate is ultrasonically cleaned with alcohol with a volume fraction of greater than or equal to 99.7%.

5. The method for preparing the perovskite-structured composite coating according to claim 1, characterized in that, Step (1), in the mixed system A, the amount-of-substance ratio of strontium element, zirconium element, A element and B element is (1+ω):x:y:(1-x-y); -0.2≤ω≤0.2, 0.6≤x<1, 0<y≤0.4; each raw material is counted by Sr 1+ω (Zr x A y B 1-x-y )O 3+δ , then the amount-of-substance concentration of Sr 1+ω (Zr x A y B 1-x-y )O 3+δ in the mixed system A is 0.8-2.0 mol / L; In step (2), the mass of the metal oxide particles of element Re is 5-40 wt% of the mass of mixed system A; the particle size of the metal oxide particles of element Re is 0.1-1 μm; the dispersant is polyacrylic acid, the average relative molecular mass of polyacrylic acid is M.W~3000, and the mass of the metal oxide particles of element Re is 0.5-5 wt%; In step (3), the mass of the ball milling beads is 1-3 times the mass of mixed system B; the ball milling speed is 47-86 rpm, and the ball milling time is 0.5-4 h; In step (4), the pretreatment method of the metal substrate is: first, the metal substrate is polished with 50-800 mesh water sandpaper in sequence, then white corundum with a mesh of 24 is used to perform sand blasting treatment on the surface of the metal substrate, and after the sand blasting treatment, the metal substrate is ultrasonically cleaned with alcohol with a volume fraction of greater than or equal to 99.7%; The process conditions of the solution plasma spraying process are: current is 260-300 A, total gas flow is 260-300 slpm, and the ratio of argon, hydrogen and nitrogen is 60: (10-20): (20-30); the spraying distance is 80-100 mm.

6. Use of a perovskite structure composite coating, characterized in that, The perovskite structure composite coating prepared by the preparation method of claim 1 is sprayed on the surface of a high-temperature alloy material in a high-temperature working environment to play a role of heat insulation and cooling.

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