Crystal-amorphous composite Zr-Si-O barrier layer material and preparation method and application thereof

Abstract

The invention discloses a crystal-amorphous composite Zr-Si-O barrier layer material and a preparation method and application thereof, and belongs to the technical field of functional coating materials. The material of the crystal-amorphous composite Zr-Si-O barrier layer comprises zirconium oxide crystal grains and amorphous SiO2, and the amorphous SiO2 covers the surfaces of the zirconium oxide crystal grains to form a coating layer. The crystal-amorphous composite Zr-Si-O barrier layer material can make up for the defects of phase change, cracking, poor surface compactness and the like of the existing barrier layer material at high temperature, and has high-temperature stability and low emissivity performance at the same time. The crystal-amorphous composite Zr-Si-O barrier layer material provided by the invention adopts an electron beam evaporation process, and has the advantages of high oxide deposition rate, uniform prepared surface layer, high compactness, low process temperature, simple method, short period, low cost and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional coating materials, and particularly relates to a crystal-amorphous composite Zr-Si-O barrier layer material, a preparation method thereof, and an application thereof. Background Art

[0002] With the continuous upgrading of stealth fighter jets, the temperature resistance requirements for high-temperature infrared low-emissivity thin films on the rear components of aircraft engines are constantly increasing, and their temperature resistance needs to reach above 900 °C. Currently, high-temperature infrared low-emissivity thin films are usually coated on the surfaces of components made of Ni-based superalloys. To simultaneously meet the comprehensive performance requirements such as high-temperature stability and ultra-low high-temperature infrared emissivity, noble metal thin films are usually used as infrared stealth functional layers. Noble metals such as Pt / Pd have both low emissivity at high temperatures, high melting points, and excellent oxidation resistance, and can meet the requirements of high-temperature low infrared emissivity. The commonly used preparation process is magnetron sputtering coating. However, when the existing noble metal coatings such as Pt / Pd are used in a high-temperature environment above 900 °C in the engine, element diffusion easily occurs between the noble metal layer and the base metal, resulting in the destruction of the infrared function continuity and ultimately the loss of the infrared stealth effect. Therefore, to prevent high-temperature diffusion between metals, a diffusion barrier layer needs to be added.

[0003] The high-temperature infrared emissivity of noble metal thin films prepared by magnetron sputtering is closely related to the surface flatness of the thin films and is mainly controlled by the surface flatness of the substrate material. Therefore, to prepare a high-performance low-emissivity coating, a smooth and dense diffusion barrier layer is required to cooperate. In addition, as an intermediate layer, the diffusion barrier layer also needs to have good high-temperature stability and high bonding strength with the substrate and the metal layer. Therefore, the component design and preparation process of the diffusion barrier layer are the key to preparing high-temperature infrared low-emissivity coatings.

[0004] According to different diffusion barrier layer components, the current preparation processes of diffusion barrier layers in high-temperature infrared low-emissivity coatings include the microcrystalline glass / ceramic coating and sintering method, the magnetron sputtering process, and the plasma spraying process. For example, in the patent CN201410173870.9, the ZnO-Al2O3-SiO2 composite oxide is prepared by the microcrystalline glass sintering process as the diffusion barrier layer. The sintering temperature of this material is 850 °C, but the actual temperature resistance only reaches 700 °C. The sintering temperature is much higher than the service temperature, making it difficult to be applicable to high-temperature environments above 900 °C, and the high-temperature stability is poor. For example, in the patent CN201811422506.6, the YSZ ceramic diffusion barrier layer is prepared by the plasma spraying process. The intermediate barrier layer prepared by plasma spraying is porous and the surface densification is not good. Usually, the high-temperature emissivity is relatively high (above 0.15), and additional surface treatment processes such as polishing are required; moreover, the process temperature for preparing the coating by plasma spraying is relatively high, which cannot meet the actual requirements of the parts. There are also some deficiencies in preparing the composite oxide barrier layer by the magnetron sputtering process: First of all, the magnetron sputtering process is a low-temperature forming process, and the prepared oxides are usually amorphous or low-temperature stable crystal forms, which are prone to phase transformation during high-temperature use, resulting in film shrinkage and cracking. In addition, the deposition rate of oxides prepared by the magnetron sputtering process is low and the process cycle is extremely long, which is not conducive to batch production.

[0005] In summary, the barrier layers prepared by the existing process methods have problems such as poor high-temperature long-term stability, poor surface densification, high roughness, and easy cracking and phase transformation, resulting in a relatively high emissivity of the high-temperature infrared low-emissivity thin film. At the same time, the preparation process temperature is high, the process method is complex, the cycle is long, and the cost is high. Summary of the Invention

[0006] To solve the technical problems raised in the background art, the main object of the present invention is to provide a crystal-amorphous composite Zr-Si-O barrier layer material, its preparation method and application. The surface of the Zr-Si-O barrier layer material prepared by the present invention is uniform, the structure is dense, the bonding force with the substrate and the metal layer is good, and it has excellent high-temperature stability, which can make up for the deficiencies of existing barrier layer materials such as easy phase transformation and cracking at high temperatures.

[0007] To achieve the above object, the present invention provides a crystal-amorphous composite Zr-Si-O barrier layer material, which includes zirconia grains and amorphous SiO2, and the amorphous SiO2 covers the surface of the zirconia grains to form a coating layer.

[0008] Furthermore, the atomic ratio of Zr to Si in the crystal-amorphous composite Zr-Si-O barrier layer material is 1-10:1.

[0009] Furthermore, the zirconia grains are arranged in a tetragonal crystal form.

[0010] Furthermore, the particle size of the zirconia grains is 10 - 200 nm.

[0011] Furthermore, the thickness of the crystalline - amorphous composite Zr - Si - O barrier layer material is 2 - 6 μm.

[0012] On the other hand, the present invention provides a method for preparing the aforementioned crystalline - amorphous composite Zr - Si - O barrier layer material, comprising the following steps:

[0013] Mix zirconia and quartz powder and press them to obtain a target;

[0014] Vacuum the electron beam evaporation system. When the preset vacuum degree is reached, turn on the evaporation gun to preheat the target;

[0015] Send the substrate into the electron beam evaporation system for preheating. When the preset temperature is reached, adjust the setting parameters of the electron beam evaporation system, evaporate the target to deposit a coating on the surface of the substrate. When the coating reaches the required thickness, the crystalline - amorphous composite Zr - Si - O barrier layer material is obtained.

[0016] Furthermore, in the target, the atomic ratio of Zr to Si is 1 - 10:1.

[0017] Furthermore, during the evaporation of the target, the bombardment current of the electron beam is 200 - 300 mA, and the ion source current is 3.5 - 4.5 mA.

[0018] Furthermore, the background vacuum degree of the electron beam evaporation system is ≤ 2×10 -3 Pa, and the working vacuum degree is 1×10 - 2 Pa - 5×10 -2 Pa.

[0019] Furthermore, the preset temperature of the substrate is 150 - 250 °C.

[0020] On the other hand, the present invention also provides an application of the above - mentioned crystalline - amorphous composite Zr - Si - O barrier layer material in a high - temperature and low - emissivity coating.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] A crystal-amorphous composite Zr-Si-O barrier layer material provided by the present invention is prepared by an electron beam evaporation process. By controlling the process and component ratio, a crystal-amorphous composite Zr-Si-O composite oxide film is prepared. Compared with the prior art of microcrystalline glass / ceramic coating sintering method, magnetron sputtering process or plasma spraying process, it has the advantages of fast oxide deposition rate, uniform surface of the prepared layer, high density, low process temperature, simple method, short cycle and low cost.

[0023] In the crystal-amorphous composite Zr-Si-O barrier layer material of the present invention, Zr-O forms regular grains, arranged in a tetragonal crystal phase. The thermal neutron absorption cross-section of these zirconia grains is low, and it has excellent high-temperature and high-pressure corrosion resistance. Amorphous SiO2 covers the surface of the zirconia grains to form a coating layer, which plays a role in binding the grains. Due to the defects of the grains and the filling of amorphous SiO2 at the interfaces, Zr-O-Si bonds are formed between the amorphous SiO2 and Zr elements. Through the action of the Zr-O-Si bonds and non-bridging siloxane groups (Si-O-), it is beneficial to reduce the interface energy and further improve the high-temperature stability of the crystal-amorphous composite Zr-Si-O film. In addition, the presence of the amorphous SiO2 component can improve the density of the composite oxide film and has good adhesion to the substrate and the metal layer.

[0024] In summary, using the crystal-amorphous composite Zr-Si-O barrier layer material of the present invention can make up for the deficiencies of existing barrier layer materials such as phase change, cracking, and poor surface density at high temperatures, thus having both high-temperature stability and low emissivity performance at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Shows the microstructural diagram of the crystal-amorphous composite Zr-Si-O barrier layer material of Example 1 of the present invention;

[0026] Figure 2 Shows the XRD analysis result diagram of the crystal-amorphous composite Zr-Si-O barrier layer material of Example 1 of the present invention;

[0027] Figure 3 Shows the microstructural diagram of the crystal-amorphous composite Zr-Si-O barrier layer material of Example 1 of the present invention after heat treatment at 900 °C;

[0028] Figure 4 Shows the microstructural diagram of the ZrO2 barrier layer material of Comparative Example 1 of the present invention;

[0029] Figure 5 Shows the microstructural diagram of the ZrO2 barrier layer material of Comparative Example 1 of the present invention after heat treatment at 900 °C. DETAILED DESCRIPTION OF THE INVENTION

[0030] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range. The present invention will be described in detail below with reference to the embodiments.

[0031] To solve the above problems, a first aspect of the embodiments of the present invention provides a crystalline-amorphous composite Zr-Si-O barrier layer material, including zirconia grains and amorphous SiO2, and the amorphous SiO2 covers the surface of the zirconia grains to form a coating layer.

[0032] In the crystalline-amorphous composite Zr-Si-O barrier layer material of the present invention, Zr-O forms regular grains. The zirconia grains have a low thermal neutron absorption cross-section and excellent high-temperature and high-pressure corrosion resistance. The amorphous SiO2 covers the surface of the zirconia grains to form a coating layer, which plays a role in binding the grains. Due to the defects of the grains and the filling of amorphous SiO2 at the interfaces, Zr-O-Si bonds are formed between the amorphous SiO2 and Zr elements. Through the action of the Zr-O-Si bonds and non-bridging silicon-oxygen groups (Si-O-), it is beneficial to reduce the interface energy and further improve the high-temperature stability of the crystalline-amorphous composite Zr-Si-O thin film. At the same time, due to the presence of the amorphous Si-O component, the density of the composite oxide thin film can be increased, and the bonding force with the substrate and the metal layer is good, so that the barrier layer material of the present invention has both high-temperature stability and low emissivity performance.

[0033] In a preferred embodiment of the present invention, the atomic ratio of Zr to Si in the crystalline-amorphous composite Zr-Si-O barrier layer material is 1 to 10:1. For example, it can be 1:1, 2:1, 3:1, 5:1, 6:1, 8:1, 9:1, 10:1. Further preferably, it is 1 to 3:1.

[0034] In a preferred embodiment of the present invention, the zirconia grains are arranged in a tetragonal crystal form; the particle size of the zirconia grains is 10 to 200 nm. For example, it can be 10 nm, 20 nm, 40 nm, 50 nm, 60 nm, 80 nm, 100 nm, 120 nm, 140 nm, 150 nm, 160 nm, 180 nm, 200 nm.

[0035] In order to further improve the comprehensive performance of the crystalline-amorphous composite Zr-Si-O barrier layer material, making it have both excellent high-temperature stability and low emissivity performance at the same time. In a preferred embodiment of the present invention, the thickness of the crystalline-amorphous composite Zr-Si-O barrier layer material is 2-6 μm. For example, it can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm.

[0036] The second aspect of the embodiments of the present invention provides a method for preparing the aforementioned crystalline-amorphous composite Zr-Si-O barrier layer material, comprising the following steps:

[0037] Mix zirconia and quartz powder and press them to obtain a target;

[0038] Evacuate the electron beam evaporation system. When the preset vacuum degree is reached, turn on the evaporation gun to preheat the target;

[0039] Send the substrate into the electron beam evaporation system for preheating. When the preset temperature is reached, adjust the set parameters of the electron beam evaporation system, start evaporating the target to deposit a coating on the surface of the substrate. When the coating reaches the required thickness, the crystalline-amorphous composite Zr-Si-O barrier layer material is obtained.

[0040] The present invention uses an electron beam physical vapor deposition process to prepare a crystalline-amorphous composite Zr-Si-O barrier layer material, which has the advantages of fast oxide deposition rate, uniform and dense prepared surface layer, low process temperature, simple method, short cycle, and low cost compared with the existing microcrystalline glass / ceramic coating sintering method, magnetron sputtering process, or plasma spraying process.

[0041] In a preferred embodiment of the present invention, in the target, the atomic ratio of Zr to Si is 1-10:1.

[0042] In some preferred embodiments of the present invention, during the evaporation of the target, the bombardment current of the electron beam is 200-300 mA, and the ion source current is 3.5-4.5 mA; the background vacuum degree (preset vacuum degree) of the electron beam evaporation system ≤ 2×10 -3 Pa, and the working vacuum degree is 1×10 -2 Pa - 5×10 -2 Pa; the preset temperature of the substrate is 150-250 °C. By precisely controlling the process parameters of the electron beam physical vapor deposition process, the surface of the prepared crystalline-amorphous composite Zr-Si-O barrier layer material can be made denser and more uniform, and the amorphous-crystalline binding force between materials is higher, so as to further improve the high-temperature stability and low emissivity of the material.

[0043] In the third aspect of the present invention, there is also provided an application of the above-mentioned crystalline-amorphous composite Zr-Si-O barrier layer material in a high-temperature resistant and low-emissivity coating.

[0044] For the reasons described above, the crystalline-amorphous composite Zr-Si-O barrier layer material of the present invention is particularly suitable for use as a diffusion barrier layer in a high-temperature resistant and low-emissivity coating, to prevent element diffusion between the noble metal layer and the base metal at temperatures above 900 °C, which may damage the infrared function.

[0045] The following further describes the present application in detail with specific embodiments, which should not be construed as limiting the scope claimed in the present application.

[0046] Example 1

[0047] A crystalline-amorphous composite Zr-Si-O barrier layer material, comprising zirconia grains and amorphous SiO2, wherein the zirconia grains are dispersed in the amorphous SiO2, and the amorphous SiO2 covers the surface of the zirconia grains to form a coating layer. Among them, the zirconia grains are arranged in a tetragonal crystal phase, the ratio of zirconium element to silicon element is 1:1, the particle size of the zirconia grains is 50 nm, and the thickness of the barrier layer material is 3 μm.

[0048] It is prepared by an electron beam physical vapor deposition process, and the preparation process is as follows:

[0049] A columnar target is prepared by uniformly mixing zirconia and quartz powder, and the atomic ratio of Zr:Si in the target is 1:1;

[0050] The electron beam evaporation system is evacuated, and after the vacuum reaches 1×10 -3 Pa, the evaporation gun is turned on to preheat the target to 150 °C; the substrate is sent into the electron beam evaporation system for preheating. When the workpiece reaches 150 °C, the system parameters are adjusted (working vacuum 1×10 -2 Pa, bombardment current 200 mA, ion source current 4 mA), and the target is evaporated to deposit a coating on the surface of the substrate. When the coating reaches 3 μm, the crystalline-amorphous composite Zr-Si-O barrier layer material is obtained.

[0051] The microstructure characterization and XRD analysis of the above-prepared crystalline-amorphous composite Zr-Si-O barrier layer material are carried out. Its microstructure is as Figure 1 shown, the grains are fine, showing a uniform distribution, the surface is continuous and dense, without defects. The XRD analysis results are as Figure 2As shown, where 30°, 35°, and 50° are the characteristic peaks of tetragonal zirconia, while the broad peak at 25° is the typical XRD characteristic peak of amorphous SiO2. In addition, after the crystal-amorphous composite Zr-Si-O barrier layer material is heat-treated at 900 °C for 30 h, its surface microstructure is characterized, and its microstructure is as shown in Figure 3 shown. The results show that the zirconia grains increase in size after heat treatment, and the overall structure remains dense, continuous, and without defects.

[0052] The present invention further studies the influence of the preparation process parameters on the performance of the Zr-Si-O barrier layer material, and provides the crystal-amorphous composite Zr-Si-O barrier layer materials of Examples 2 to 6. The process steps refer to Example 1, and the specific process parameters are shown in Table 1.

[0053] Table 1

[0054]

[0055]

[0056] Using the crystal-amorphous composite Zr-Si-O barrier layer materials prepared in the above Examples 1 to 6 as the barrier layer of the high-temperature infrared low-emissivity film, the high-temperature infrared low-emissivity film is composed of a base layer (Ni-based superalloy), a barrier layer, and a low-infrared emissivity surface layer (Pt noble metal) stacked from top to bottom in sequence. The performance test and appearance observation of the above-prepared high-temperature infrared low-emissivity film are carried out, and the test results are shown in Table 2.

[0057] Appearance: Observe the surface of the high-temperature infrared low-emissivity film.

[0058] Tensile bond strength performance test method: GB / T 5210-2006 - "Pull-off adhesion test for paints and varnishes".

[0059] Barrier performance test method: After the high-temperature infrared low-emissivity film is kept at 900 °C for 300 h, the infrared emissivity is tested according to HB20540-2018 - "Test method for infrared emissivity of stealth materials".

[0060] Thermal shock resistance test method: AETF 63A - "Coating thermal shock test method". Specifically, the high-temperature infrared low-emissivity film is heated from room temperature to 900 °C, and after 300 cycles of air-cooling thermal shock, the appearance of the film is observed. If no defects such as wrinkling, bubbling, cracking, peeling, and flaking occur, it indicates that its thermal shock resistance is excellent.

[0061] Heat resistance test method: After the film is kept at 900 °C for 300 h, the appearance is observed and the tensile bond strength is tested.

[0062] Table 2

[0063]

[0064] By observing the surface of the high-temperature infrared low-emissivity film of this embodiment visually, the Pt-coated surface layer all exhibits a silver-white metallic luster, indicating that the surface layer has good bonding with the crystal-amorphous composite Zr-Si-O barrier layer of this embodiment, and the structure of the barrier layer material is flat. From the tensile bonding strength test, it is found that the bonding force between the barrier layer and the surface layer is excellent, and its bonding strength is 18-21 MPa, indicating that the high-temperature infrared low-emissivity film of this embodiment has excellent mechanical properties. When the high-temperature infrared low-emissivity film is heat-treated at 900 °C for 30 h, the tensile bonding strength between the barrier layer and the surface layer is tested, and it is found that the bonding strength does not decrease significantly, and at the same time, no change occurs on the surface and no cracking phenomenon is observed. Through the thermal shock resistance performance test, no obvious change occurs in the appearance of the high-temperature infrared low-emissivity film, and no wrinkling, bubbling, cracking and other phenomena occur. Through the above performance tests, it can be found that the high-temperature infrared low-emissivity film of this embodiment has excellent high-temperature stability and will not crack, bubble, undergo phase change and other problems at high temperature. In addition, according to the barrier performance test, the high-temperature infrared low-emissivity film of this embodiment still has a low emissivity at high temperature, and its emissivity is all ≤0.20.

[0065] Comparative Example 1

[0066] A ZrO2 barrier layer material is prepared by an electron beam physical vapor deposition process, and its preparation process is as follows:

[0067] The zirconia is made into a columnar target;

[0068] The electron beam evaporation system is evacuated, and after the vacuum reaches 1×10 -3 Pa, the evaporation gun is turned on to preheat the target to 150 °C; the substrate is sent into the electron beam evaporation system for preheating. When the workpiece reaches 150 °C, the system parameters are adjusted (working vacuum degree 1×10 -2 Pa, bombardment current 200 mA, ion source current 4 mA), and the target is evaporated to deposit a coating on the surface of the substrate. When the coating reaches 3 μm, the ZrO2 barrier layer material is obtained.

[0069] The microstructure of the obtained ZrO2 barrier layer material is characterized, and its microstructure is as Figure 4 shown. It can be observed from the figure that the grains of pure zirconia crystals are coarse and the surface density is poor. In addition, after the ZrO2 barrier layer material is heat-treated at 900 °C for 10 h, the surface microstructure is characterized, and its microstructure is as Figure 5As shown, significant phase changes occur due to heating, resulting in material cracking. Furthermore, when used as a barrier layer, the emissivity of the high-temperature infrared low-emissivity film is relatively high, reaching 0.76.

[0070] In summary, the Zr-Si-O barrier layer material prepared by the present invention has a uniform surface, a dense structure, good bonding with the substrate and the metal layer, excellent high-temperature stability, and can compensate for the deficiencies of existing barrier layer materials, such as easy phase change and cracking at high temperatures. When the Zr-Si-O barrier layer material is applied to the high-temperature infrared low-emissivity film, it can effectively prevent element diffusion between the metal layer and the base metal at high temperatures and effectively reduce the emissivity of the high-temperature infrared low-emissivity film at high temperatures.

[0071] The embodiments described above only represent the implementation modes of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. The present invention can also be implemented in other specific ways or other specific forms without departing from the gist or essential features of the present invention. Therefore, the described implementation modes should be regarded as illustrative rather than restrictive in any aspect. The scope of the present invention should be defined by the appended claims, and any equivalent changes to the intention and scope of the claims should also be included within the scope of the present invention.

Claims

1. A crystalline-amorphous composite Zr-Si-O barrier layer material, characterized in that: It comprises zirconium oxide grains and amorphous SiO2, wherein the amorphous SiO2 covers the surface of the zirconium oxide grains to form a coating layer.

2. The crystalline-amorphous composite Zr-Si-O barrier layer material according to claim 1, characterized in that: The atomic ratio of Zr to Si in the crystalline-amorphous composite Zr-Si-O barrier layer material is 1 to 10:

1.

3. The crystalline-amorphous composite Zr-Si-O barrier layer material according to claim 2, characterized in that: The zirconium oxide crystal grains are arranged in a tetragonal crystal phase, and the particle size of the zirconium oxide crystal grains is 10 to 200 nm.

4. The crystalline-amorphous composite Zr-Si-O barrier layer material according to any one of claims 1 to 3, characterized in that: The thickness of the crystalline-amorphous composite Zr-Si-O barrier layer material is 2-6 μm.

5. A method for preparing a crystalline-amorphous composite Zr-Si-O barrier layer material as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: The zirconium oxide and quartz powder are mixed and pressed to obtain a target material; The electron beam evaporation system is evacuated to a vacuum state, and when a preset vacuum degree is reached, an evaporation gun is turned on to preheat the target material; The substrate is sent into the electron beam evaporation system for preheating. When the preset temperature is reached, the setting parameters of the electron beam evaporation system are adjusted, and the target material is started to be evaporated to deposit a coating on the surface of the substrate. When the coating reaches the required thickness, the crystalline-amorphous composite Zr-Si-O barrier layer material is obtained.

6. The method for preparing the crystalline-amorphous composite Zr-Si-O barrier layer material according to claim 5, characterized in that: In the target material, the atomic ratio of Zr to Si is 1 to 10:

1.

7. The method for preparing the crystalline-amorphous composite Zr-Si-O barrier layer material according to claim 6, characterized in that: During the target material evaporation process, the bombardment current of the electron beam is 200-300 mA, and the ion source current is 3.5-4.5 mA.

8. The method for preparing the crystalline-amorphous composite Zr-Si-O barrier layer material according to claim 5, characterized in that: The background vacuum degree of the electron beam evaporation system is ≤2×10 -3 Pa, working vacuum degree is 1×10 -2 Pa~5×10 - 2 Pa.

9. The method for preparing a crystalline-amorphous composite Zr-Si-O barrier layer material according to any one of claims 5 to 8, characterized in that: The preset temperature of the substrate is 150-250°C.

10. Use of the crystalline-amorphous composite Zr-Si-O barrier layer material according to any one of claims 1 to 4 in a high temperature resistant low emissivity coating.

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