Composite coating structure with low-ductility functional coating matched with high-ductility base material

Abstract

The invention relates to a composite coating structure with a low-ductility functional coating matched with a high-ductility base material, the composite coating structure covers the surface of a base material, a coating formed by combining a low-ductility material and a high-ductility material is adopted, the low-ductility material is an active material which plays a role, and the high-ductility material is an active material which plays a role. The low-ductility material and the high-ductility material form reticular structure pattern distribution in the composite coating structure, the high-ductility material forms a framework of a reticular structure, and the low-ductility material is embedded into each unit body defined by the framework. Compared with the prior art, the method has the advantages that the ductility of the low-ductility functional coating is improved, so that the low-ductility functional coating is matched with a high-ductility substrate material, and the mechanical property and the functional stability of the original functional coating are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface coating preparation, and relates to a composite coating structure in which a low-ductility functional coating is matched with a high-ductility substrate. Background Art

[0002] In modern industrial and technological applications, the use of coating materials is extremely extensive. Coatings are not only used to protect substrate materials from environmental corrosion, oxidation, and mechanical wear, but also endow materials with special functions, such as electrical conductivity, insulation, high-temperature resistance, and drag reduction. Therefore, the performance of coatings is crucial for improving the lifespan and functionality of the overall material. The quality and stability of high-performance coatings directly affect the reliability and application effect of devices. In various application scenarios, from electronic devices to energy batteries, from aerospace devices to building structures, the selection and design of coatings are important factors determining the stability of the system.

[0003] However, many existing functional coatings often face the problem of mismatched ductility with substrate materials during application. The ductility difference between the coating and the substrate often causes the low-ductility coating to crack or peel off under stress, especially when the substrate material deforms, bends, or stretches. This failure not only reduces the protective effect of the coating but may also lead to the loss of functionality, such as electrical conductivity, corrosion resistance, or other properties. Therefore, in order to enhance the adaptability between the coating and the substrate material, it is necessary to modify the coating to match its ductility with the substrate material, avoid cracking, and maintain the functional integrity of the coating.

[0004] Doping a high-ductility material into a low-ductility material is a commonly used material modification method. After modification, a structure in which the high-ductility material links the low-ductility material is formed inside the material. When subjected to deformation, the stretching of the high-ductility material is used to resist the formation of cracks, which can effectively improve the ductility of the original material and avoid the generation of cracks.

[0005] Searching the existing literature, it is found that Patent CN107519766A proposes a polymer-based ceramic ultrafiltration composite material. A silane coupling layer is provided on the surface of the ceramic-based membrane, and a polyimide layer is further provided on the surface of the silane coupling layer. The highly ductile polyimide polymer is used to improve the mechanical properties of the originally low-ductility ceramic membrane and enhance the mechanical properties of the membrane during operation. Patent CN209708678U discloses a ceramic refractory cable with good ductility. An aluminum core and a carbon fiber layer are filled in the refractory protection sleeve made of the original ceramized silicone rubber material, and a metal aluminum coating is wrapped outside the carbon fiber layer. The good ductility of the metal aluminum and the carbon fiber layer is used to enhance the overall ductility of the cable, facilitating the transportation and laying of the cable. These patents have all confirmed the feasibility of doping flexible and highly ductile materials into the originally low-ductility materials that are prone to damage under tension, thereby improving the ductility of the original materials and resisting crack generation.

[0006] However, both of the above two patents have certain defects. First, the distribution methods of the highly ductile materials and the low-ductile materials are both to coat the highly ductile materials on the inner surface or the outer surface of the low-ductile materials to form a multi-layer structure. However, this structure cannot well penetrate the highly ductile materials into the low-ductile materials, only improving the ductility of the materials at the junction, and the large area of the undoped low-ductile materials inside is still in a brittle and crack-prone state. Patent CN113178663A proposes a structure and preparation method of a composite diaphragm, mixing the original layered polymer coating and ceramic particle coating into a slurry and coating it on the surface of the diaphragm, making use of both the heat resistance of the ceramic and the superior mechanical properties of the polymer to form a structure in which the polymer and the ceramic material penetrate and cooperate with each other. However, the existing defect is that it cannot ensure the uniformity of the composite coating of the polymer and the ceramic material. Even if it is mixed into a slurry for coating, the uniformity of the slurry cannot be guaranteed in actual production. The polymer and the ceramic material tend to be randomly distributed, and the patterns and morphologies of their distributions in the composite coating cannot be controlled, resulting in a lot of randomness in the properties of the coating.

[0007] However, if high-ductility materials and low-ductility materials can be distributed in a specific and controllable pattern within a single layer to prepare a composite coating with precise structure, the uniformity and stability of the coating properties can be effectively ensured. At the same time, different patterns can also be customized according to the needs of the coating properties. After retrieval, it is found that Patent CN117552267A proposes a waterproof and tensile cardboard structure, in which a honeycomb board structure is arranged in the middle layer, improving the stability and tensile resistance of the cardboard. Patent CN111893362A discloses a three-dimensional network-structured high-entropy alloy and its preparation method. The prepared high-entropy alloy has a special three-dimensional network structure, consisting of equiaxed ultrafine grains forming a three-dimensional network "shell", and the "shell" encloses a "core" composed of coarse grains inside. By using the coordinated deformation of each characteristic tissue, the uniform elongation rate of the high-entropy alloy is increased from less than 5% to not less than 11%. The above two patents have both verified the role of special network structures in improving the ductility of materials. However, the problem existing in both patents is that the network structure proposed in Patent CN111893362A only targets a single material of high-entropy alloy, and the honeycomb board structure arranged in the middle layer proposed in Patent CN1117552267A also only targets a single material such as cardboard. For the case of composite of multiple materials, that is, the problem of how to design a high-ductility composite coating by using the role of network structure in improving ductility remains to be solved.

[0008] Zhang et al. proposed a self-supporting metal ceramic nanosheet synthesized by the molecular structural reaction of high entropy alloy nanocrystals and polyvinyl alcohol (PVA) (Zhang, Jingyang et al. "Strong yet Ductile High Entropy Alloy Derived Nanostructured Cermet." Nano letters 22.18 (2022): 7370-7377). The metal ceramic nanosheet formed a special structure in which metal nanocrystals were surrounded by complex amorphous oxides and interspersed with PVA decomposition residues; the prepared strong and tough high entropy alloy-derived nanostructured metal ceramics have super strength (~3.2 GPa) and excellent ductility (~50%). Compared with the fracture elongation of less than 20% of traditional bulk high entropy alloys and metal film ceramics, the fracture elongation of high entropy alloy ceramics is increased to 50%, overcoming the long-standing brittleness problem of traditional metal ceramics. The new metal ceramic nanosheets prepared by Zhang et al. take advantage of the good plasticity and ductility of amorphous oxides and PVA decomposition residues, surround the high entropy alloy nanocrystals, and achieve the improvement of the ductility of high entropy alloy ceramics. However, the problem is that this type of metal ceramic nanosheet is made by the reaction of high entropy alloy nanocrystals and PVA. In the obtained composite nanosheets, the distribution of high entropy alloy nanocrystals, amorphous oxides and PVA decomposition residues in the nanosheets cannot be accurately controlled, and it is difficult to ensure the stability of the properties of the nanosheets prepared before and after.

[0009] Kurapova et al. proposed a nickel aluminide-based composite doped with reduced graphene oxide (rGO) (Kurapova, Olga Yu et al. “Tensile Properties, Hardness and Phase Formation of the Nickel Aluminides Based Composites Doped with Reduced Graphene Oxide (Al-Ni-rGO).” Journal of alloys and compounds 928 (2022): 166912). Using an improved powder metallurgy technique, 0.5 wt% of reduced graphene oxide was introduced into the Al-Ni system. The ductility of the prepared nickel aluminide-based composite doped with rGO was significantly improved. Compared with the nickel aluminide-based composite with the same composition prepared by the same process, the elongation at break of the nickel aluminide alloy with the introduced rGO reinforcement phase increased from 9% to 19%. After adjusting the mass fractions of nickel and aluminum, an elongation at break of 43% could be achieved, improving the problem of the large brittleness and low ductility of nickel aluminide alloys during application. Similar to the research of Zhang et al., although Kurapova et al. also improved the ductility of the original material by doping with a highly ductile material, the distribution structure of the highly ductile dopant rGO and the nickel aluminide alloy was not precisely designed controllably. The uncontrollability and randomness of the distribution structures of the two materials with high and low ductility easily led to the non-uniformity and randomness of the properties of the composite material. Summary of the Invention

[0010] The object of the present invention is to overcome at least one defect such as the poor matching between a low-ductility functional coating and a high-ductility substrate and the easy generation of cracks in the low-ductility functional coating when subjected to tension in the existing technologies described above, and to provide a composite coating structure in which a low-ductility functional coating is matched with a high-ductility substrate. The present invention realizes the improvement of the ductility of the low-ductility functional coating to match the high-ductility substrate material, thereby improving the mechanical properties and functional stability of the original functional coating.

[0011] The object of the present invention can be achieved by the following technical solutions:

[0012] One of the technical solutions of the present invention is to provide a composite coating structure in which a low-ductility functional coating is matched with a high-ductility substrate. The composite coating structure covers the surface of the base material, and a coating composed of a combination of a low-ductility material and a high-ductility material is used. The low-ductility material is an active material that plays a function, but its ductility is lower than that of the base material. The high-ductility material is used to make up for the ductility of the original coating, has good adhesion to both the low-ductility material and the base material, and does not affect the original functionality of the low-ductility material. The low-ductility material and the high-ductility material form a reticular structure pattern distribution in the composite coating structure. The high-ductility material constitutes the skeleton of the reticular structure, and the low-ductility material is embedded in each unit body surrounded by the skeleton, that is, filled in each hollow unit body, forming a layer distribution with the high-ductility material and coordinating with each other during the tensile deformation process.

[0013] Dope the high-ductility material into the low-ductility material to improve the ductility and tensile properties of the original low-ductility coating;

[0014] At the same time, let the high-ductility material form a reticular structure skeleton with a specific pattern, and utilize the uniform dispersion of stress by the reticular structure to improve the ductility and tensile properties of the composite coating.

[0015] Under this reticular structure, on the one hand, a structure in which the high-ductility material links the low-ductility material is formed, making up for the ductility defect of the original coating material and enhancing the anti-fracture ability of the coating during stretching; on the other hand, the reticular structure is used to evenly disperse the tensile stress, reduce stress concentration, and the redundancy of the grid can also prevent the spread of cracks, so as to safely wrap the material with functionality but low ductility in the high-ductility material network, improving the tensile strength and durability of the coating.

[0016] Furthermore, the base material includes a metal or non-metal material with good ductility. Among them, the metal material includes pure metal or alloy, and the non-metal material includes polymer, carbon nanomaterial or inorganic compound.

[0017] Furthermore, the low-ductility material includes materials that are prone to fracture under tension, such as glass, ceramic or low-ductility carbon-based materials.

[0018] Furthermore, the high-ductility material includes materials that are prone to ductility, such as metal, rubber or polymer.

[0019] Furthermore, the pattern includes a polygon composed of straight edges or a geometric shape surrounded by smooth curves. The patterns are combined into a regular or irregular reticular structure. The high-ductility material constitutes the skeleton of the reticular structure, that is, the edge. By virtue of the uniform dispersion of stress generated during the stretching process by the reticular structure, the tensile properties of the high-ductility material are enhanced.

[0020] Furthermore, the mesh structure includes a honeycomb mesh structure, a checkerboard mesh structure, a randomly distributed polygonal mesh structure, or a bionic tissue mesh structure to enhance the mechanical properties of different aspects of the coating.

[0021] By adjusting the geometric parameters of the mesh structure framework of the highly ductile material, a composite coating with good performance can be customized.

[0022] Furthermore, the low-ductility material and the high-ductility material may have a thickness difference according to actual requirements. For the low-ductility material, its specific functions need to be exerted. If the low-ductility material is too thick, it may affect the flexibility of the entire coating. If the low-ductility material is too thin, it cannot provide sufficient functional effects. Similarly, for the framework of the high-ductility material, its stress buffering ability and crack resistance ability also require a certain thickness to ensure. Therefore, for specific high- and low-ductility coating materials, the thickness difference between the low-ductility material and the high-ductility material can be appropriately adjusted to achieve a balance between the crack resistance and functional strength of the composite coating. The thickness ratio of the low-ductility material to the high-ductility material is (1 - 3):(1 - 3).

[0023] Regarding the specific thickness of the low-ductility material and the high-ductility material, for the low-ductility material, its functional strength is proportional to its thickness. The thickness of the low-ductility material can be selected according to the required functional strength. In practice, coatings with different thicknesses can be prepared, and physical quantities related to the functional strength can be calibrated, and then an appropriate thickness can be selected.

[0024] For the high-ductility material, it mainly plays the role of high fracture toughness and strong plastic deformation ability in the composite coating. Using the high fracture toughness of the high-ductility material, the original brittle fracture of the low-ductility material is transformed into the ductile fracture of the composite coating, that is, using the plastic deformation of the high-ductility material to make the crack tip "blunt", reducing the stress concentration at the crack, and converting the stress energy at the crack tip into the deformation energy of the material, thereby preventing crack propagation. The greater the thickness of the high-ductility material, the larger the plastic deformation region inside the material, and the correspondingly greater the energy required for crack generation and propagation, thus enhancing the crack resistance ability of the coating during the stretching process.

[0025] Furthermore, the thicknesses of both the low-ductility material and the high-ductility material are 10 nm - 100 μm, which can not only achieve the required functional strength of the coating but also endow the coating with certain crack resistance performance.

[0026] As a preferred technical solution, the thickness of the substrate material is 10 - 100 μm.

[0027] The geometric parameters of the network structure framework formed by the highly ductile material also affect the functional strength and crack resistance of the composite coating, mainly reflected in the frame width and inner frame length of the framework.

[0028] Furthermore, in terms of the frame width of the framework, when the thickness of the highly ductile material is constant, if the frame width of the framework is relatively wide, the distribution area of the highly ductile material in the composite coating will increase, enabling the highly ductile material to more effectively absorb the energy of tensile stress and disperse the energy through plastic deformation, thereby enhancing the crack resistance of the composite coating. However, the disadvantage is that an overly wide framework will occupy the space of the composite coating, reducing the distribution density of the low-ductility material and affecting the functional strength of the composite coating; if the frame of the framework is relatively narrow, it will lead to insufficient stress dispersion of the highly ductile material, resulting in stress concentration in some areas of the coating during tensile stress, which is prone to the generation and propagation of cracks; therefore, in order to balance the crack resistance and functional strength of the composite coating, the ratio of the frame width of the highly ductile material framework to the thickness of the highly ductile material is (1 - 4):(1 - 2).

[0029] Furthermore, in terms of the inner frame length of the framework, when the thickness of the highly ductile material and the frame width of the framework are constant, if the inner frame length of the framework is relatively long, the area of a single unit enclosed by the framework will increase, and the proportion of the low-ductility material in the composite coating will increase, which is helpful for the performance of the functional material. However, the disadvantage is that the support area of the highly ductile material framework becomes sparse, the stress dispersion effect is weak, and the crack resistance of the coating is reduced; if the inner frame length of the framework is relatively short, the density of the unit will increase, the connection between the highly ductile material frameworks will be closer, which is more conducive to stress dispersion and preventing the initiation and propagation of cracks. However, the disadvantage is that it weakens the filling rate of the low-ductility material, thereby reducing the overall functional strength of the composite coating; therefore, in order to balance the crack resistance and functional strength of the composite coating, the ratio of the inner frame length of the highly ductile material framework to the frame width is (2 - 20):1.

[0030] One of the technical solutions of the present invention is to provide an application of the composite coating structure in which the low-ductility functional coating is matched with the highly ductile substrate, and the composite coating structure is applied to the surfaces of workpieces that are repeatedly deformed, such as flexible electronic devices, battery plates, and medical devices, to improve the mechanical stability and cycle life of the workpieces.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) In the design of the present invention, a highly ductile material is doped into a low-ductile material coating to form a distribution of a multi-material combination on the surface of the substrate material, so as to improve the ductility of the low-ductile functional coating to match the highly ductile substrate material. While maintaining the original functionality of the coating, cracks are avoided during the deformation process of the coating, and the expansion of cracks can also be prevented, thereby improving the mechanical properties and functional stability of the original functional coating; a specific network structure distribution pattern of the low-ductile material and the highly ductile material is designed, with the highly ductile material as the skeleton of the network structure and the low-ductile material embedded in the unit body surrounded by the network skeleton. When the two are deformed under tension, they coordinate with each other, and the network structure is used to disperse the stress, further enhancing the ductility and tensile strength of the composite coating;

[0033] (2) The design of the present invention precisely defines the distribution positions of the highly ductile material and the low-ductile material in the composite coating, so that the coating with a specific network structure has more uniform and stable properties when produced; at the same time, different network structure patterns can be designed according to needs, which can be regular or irregular patterns, so that the coating has different mechanical properties; this design structure has strong expandability and can promote the wider and more stable application of coating materials. Brief Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of the composite coating structure in which the low-ductile functional coating matches the highly ductile substrate in Embodiment 1 of the present invention;

[0035] Figure 2 It is a schematic structural diagram of the composite coating structure in which the low-ductile functional coating matches the highly ductile substrate in Embodiment 2 of the present invention.

[0036] Explanation of the Marks in the Figures:

[0037] 1 - Low-ductile material, 2 - Highly ductile material, 3 - Substrate material. Detailed Embodiments

[0038] The present invention will be described in detail below in conjunction with specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and the detailed implementation methods and specific operation processes are given, but the protection scope of the present invention is not limited to the following embodiments.

[0039] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third", etc. are used to describe common objects, only representing different instances referring to the same object, rather than implying that the objects described in this way must be in a given order, whether in terms of time, space, sorting, or any other way.

[0040] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] Example 1:

[0042] A composite coating structure in which a low-ductility functional coating is matched with a high-ductility substrate, as Figure 1 shown, covering the surface of the base material 3, is a distributed coating composed of a combination of a low-ductility material 1 and a high-ductility material 2. The low-ductility material 1 is an active material that performs functions, but its ductility is lower than that of the base material 3. The high-ductility material 2 is used to make up for the ductility of the original coating, has good adhesion to both the low-ductility material 1 and the base material 3, and does not affect the performance of the original functions of the low-ductility material 1. The low-ductility material 1 and the high-ductility material 2 form a specific reticular structure pattern distribution within the composite coating structure. The high-ductility material 2 constitutes the skeleton of the reticular structure, and the low-ductility material 1 is embedded in each unit enclosed by the skeleton, that is, filled in each hollow unit, forming a layer of distribution with the high-ductility material 2 and coordinating with each other during the stretching deformation process;

[0043] Doping the high-ductility material 2 into the low-ductility material 1 to improve the ductility and tensile properties of the original low-ductility coating;

[0044] At the same time, making the high-ductility material 2 form a reticular structure skeleton with a specific pattern, and using the reticular structure to evenly disperse the stress to improve the ductility and tensile properties of the composite coating;

[0045] Under this network structure, on the one hand, a structure is formed in which the highly ductile material 2 links the low ductility material 1, making up for the ductility defects of the original coating material and enhancing the anti-fracture ability of the coating when it is stretched; on the other hand, the network structure is used to evenly disperse the tensile stress, reduce stress concentration, and the redundancy of the grid can also prevent the spread of cracks, so that the material with functionality but low ductility can be safely wrapped in the network of the highly ductile material 2, improving the tensile strength and durability of the coating;

[0046] The substrate material 3 includes metals or non-metals with good ductility. The metal materials include pure metals (such as copper or aluminum) or alloys (such as stainless steel or titanium alloy), and the non-metal materials include polymers (such as polyamide, polyethylene or polyurethane), carbon nanomaterials (such as carbon nanofibers) or inorganic compounds (such as boron nitride). In this embodiment, the substrate material 3 is preferably a pure metal (copper);

[0047] The low ductility material 1 includes materials that are prone to fracture under tension, such as glass (such as quartz glass or borosilicate glass), ceramics (such as zirconia, silicon carbide or silicon nitride), or low ductility carbon-based materials (such as graphite). In this embodiment, the low ductility material 1 is preferably a low ductility carbon-based material (graphite);

[0048] The highly ductile material 2 includes materials that are prone to extension, such as metals (such as gold, silver, copper, aluminum, nickel, niobium or platinum), rubbers (such as styrene-butadiene rubber, nitrile rubber or fluororubber), or polymers (such as polytetrafluoroethylene or polyurethane). In this embodiment, the highly ductile material 2 is preferably a polymer (polyurethane);

[0049] The pattern includes polygons composed of straight edges or geometric shapes surrounded by smooth curves (such as circles or ellipses). The patterns are combined into regular or irregular network structures. The highly ductile material 2 forms the skeleton of the network structure, that is, the edges. By virtue of the uniform dispersion of the stress generated during the stretching process by the network structure, the tensile performance of the highly ductile material 2 is enhanced;

[0050] The network structure includes a honeycomb network structure, a checkerboard network structure, a randomly distributed polygon network structure or a bionic tissue network structure (such as a turtle shell-like network structure, a human skin-like network structure or a plant cell wall-like network structure) to improve the mechanical properties of different aspects of the coating. In this embodiment, a regular honeycomb network structure is preferably used;

[0051] By adjusting the geometric parameters of the network structure skeleton of the highly ductile material 2, a composite coating with good performance can be customized;

[0052] The low-ductility material 1 and the high-ductility material 2 may have a thickness difference according to actual requirements. For the low-ductility material 1, its specific functions need to be exerted. If the low-ductility material 1 is too thick, it may affect the flexibility of the entire coating. If the low-ductility material 1 is too thin, it cannot provide sufficient functional effects. Similarly, for the skeleton of the high-ductility material 2, its stress buffering ability and crack resistance also require a certain thickness to ensure. Therefore, for specific high- and low-ductility coating materials, the thickness difference between the low-ductility material 1 and the high-ductility material 2 can be appropriately adjusted to achieve a balance between the crack resistance and functional strength of the composite coating. The thickness ratio of the low-ductility material 1 to the high-ductility material 2 is (1 - 3):(1 - 3), and preferably 1:1.5 in this embodiment.

[0053] Regarding the specific thicknesses of the low-ductility material 1 and the high-ductility material 2, for the low-ductility material 1, its functional strength (such as high-temperature resistance, corrosion resistance, conductivity) is proportional to its thickness. The thickness of the low-ductility material 1 can be selected according to the required functional strength. In practice, coatings with different thicknesses can be prepared, and physical quantities related to the functional strength can be calibrated, and then an appropriate thickness can be selected.

[0054] For the high-ductility material 2, it mainly plays the role of its high fracture toughness and strong plastic deformation ability in the composite coating. Using the high fracture toughness of the high-ductility material 2, the original brittle fracture of the low-ductility material 1 is transformed into the ductile fracture of the composite coating, that is, using the plastic deformation of the high-ductility material 2 to make the crack tip "blunt", reducing the stress concentration at the crack, and converting the stress energy at the crack tip into the deformation energy of the material, thereby preventing crack propagation. The greater the thickness of the high-ductility material 2, the larger the plastic deformation region inside the material, and the correspondingly greater the energy required for crack generation and propagation, thus enhancing the crack resistance ability of the coating during the stretching process.

[0055] The common thickness of the coating is 10 nm - 100 μm. In this embodiment, the thickness of the low-ductility material 1 is selected as 2 μm, and the thickness of the high-ductility material 2 is 3 μm, which not only achieves the required functional strength of the coating but also enables the coating to have a certain crack resistance performance.

[0056] The substrate material 3 is a pure metal foil, and the common thickness is 10 - 100 μm, and preferably 35 μm in this embodiment.

[0057] The geometric parameters of the honeycomb-like network structure skeleton formed by the high-ductility material 2 also affect the functional strength and crack resistance performance of the composite coating, mainly reflected in the frame width and the inner frame length of the skeleton. Here, the inner frame length specifically refers to the inner side length of a single hexagonal unit in the honeycomb-like network structure.

[0058] In terms of the border width of the framework, when the thickness of the highly ductile material 2 is constant, if the border width of the framework is relatively wide, the distribution area of the highly ductile material 2 in the composite coating will increase, enabling the highly ductile material 2 to more effectively absorb the energy of tensile stress and disperse the energy through plastic deformation, thereby enhancing the crack resistance of the composite coating. However, the disadvantage is that an overly wide framework will occupy the space of the composite coating, reducing the distribution density of the low ductility material 1 and affecting the functional strength of the composite coating. If the border of the framework is relatively narrow, it will lead to insufficient stress dispersion of the highly ductile material 2, resulting in stress concentration in some areas of the coating during tensile stress, which is prone to the generation and expansion of cracks. Therefore, in order to balance the crack resistance and functional strength of the composite coating, the ratio of the border width of the highly ductile material 2 framework to the thickness of the highly ductile material 2 is (1 - 4):(1 - 2), and it is preferably 1:1 in this embodiment.

[0059] In terms of the inner border length of the framework, when the thickness of the highly ductile material 2 and the border width of the framework are constant, if the inner border length of the framework is relatively long, the area of a single unit enclosed by the framework increases, and the proportion of the low ductility material 1 in the composite coating increases, which helps to exert the performance of the functional material. However, the disadvantage is that the support area of the highly ductile material 2 framework becomes sparse, the stress dispersion effect is weak, and the crack resistance of the coating is reduced. If the inner border length of the framework is relatively short, the density of the unit cells increases, the connection between the highly ductile material 2 frameworks is closer, which is more conducive to stress dispersion and prevents the initiation and expansion of cracks. However, the disadvantage is that it weakens the filling rate of the low ductility material 1, thereby reducing the overall functional strength of the composite coating. Therefore, in order to balance the crack resistance and functional strength of the composite coating, the ratio of the inner border length of the highly ductile material 2 framework to the border width is (2 - 20):1, and it is preferably 5:1 in this embodiment.

[0060] Therefore, for the geometric parameters of the honeycomb-like network structure in this embodiment, the side length of each regular hexagon unit is set to 15 μm, and the border width is set to 3 μm, ensuring that the highly ductile material 2 provides sufficient support force, enabling the composite coating to have a certain crack resistance, and at the same time not weakening the effective coverage area of the low ductility material 1, so that the composite coating can better exert its original function.

[0061] Based on this embodiment, by adjusting the geometric parameters of the honeycomb-like network structure, that is, the border width and the inner border length of the framework, the distribution structure of the low ductility material 1 and the highly ductile material 2 in the composite coating can be precisely designed and adjusted. Parameters such as the relative position, distribution density, and uniformity of the low ductility material 1 and the low ductility material 2 in the composite coating can all be reflected by the geometric parameters of the honeycomb-like network structure, effectively ensuring the stability of the coating properties.

[0062] In this embodiment, the improvement of the mechanical properties of the coating by the honeycomb-like network structure lies in two aspects. Firstly, the highly ductile material 2 and the low-ductile material 1 in the honeycomb-like network structure are evenly distributed in the same layer. When the coating is subjected to tensile stress, the stress can be evenly dispersed, reducing stress concentration, thereby significantly improving the ductility of the coating and matching with the highly ductile substrate material 3, ensuring the integrity of the coating structure during operation. Secondly, the framework in the honeycomb-like network structure forms a continuous support network in the coating, with sufficient redundancy. Even if a crack appears in a certain place, the stress can be shared by the surrounding structure to prevent the crack from further expanding.

[0063] The combined action of the high- and low-ductile materials improves the ductility of the composite coating to match that of the substrate material 3, without losing its original functionality, enabling the coating to exhibit excellent crack resistance and functional stability under tension.

[0064] Example 2:

[0065] A composite coating structure in which a low-ductile functional coating is matched with a high-ductile substrate is basically the same as that in Example 1, except that, as Figure 2 shown, the network structure selects an irregular randomly distributed polygonal network structure;

[0066] The substrate material 3 selects a polymer (polyamide), the low-ductile material 1 selects a ceramic (silicon carbide), and the high-ductile material 2 selects a metal (niobium);

[0067] Similar to Example 1, in order to balance the crack resistance and functional strength of the composite coating, the thickness of the low-ductile material 1 is selected as 100 nm, the thickness of the high-ductile material 2 is selected as 200 nm, and the thickness of the substrate material 3 is selected as 25 μm;

[0068] For the geometric parameters of the randomly distributed polygonal network structure, which are the same as those in Example 1, in order to balance the crack resistance and functional strength of the composite coating, the border width of the framework is selected as 400 nm. Regarding the inner border length of the framework, here the inner border length specifically refers to the inner side length of each polygonal unit in the randomly distributed polygonal network structure. Since the network structure pattern is composed of various polygons with different shapes, the inner border length of the framework ranges from 1 to 5 μm;

[0069] The difference between the randomly distributed polygon mesh structure in this embodiment and that in Embodiment 1 lies in that, on the basis of this embodiment, not only can the distribution structure of the low-ductility material 1 and the high-ductility material 2 in the composite coating be accurately designed and adjusted by adjusting the width of the skeleton border and the length of the inner border, thereby changing the tensile properties and functional strength of the composite coating; but also the number of sides of one or some polygons, the average value of the side lengths of one or some polygons, the standard deviation of the side lengths of one or some polygons, etc. in different regions can be changed to change parameters such as the distribution density and uniformity of the low-ductility material 1 and the low-ductility material 2 in the composite coating, and these parameters can be accurately reflected by the geometric parameters of the randomly distributed polygon mesh structure, so as to realize the differential setting of the performance of different regions of the composite coating, making the coating performance anisotropic and applicable to more working scenarios under complex stresses.

[0070] In this embodiment, when the composite coating is subjected to tension, the randomly distributed polygon mesh structure can exhibit a deformation mode similar to that of human skin tissue, disperse stress, and effectively improve the tensile properties of the high-ductility material 2 skeleton; at the same time, the low-ductility material 1 is filled in the mesh skeleton, and the two materials with high and low ductility are coordinated with each other during the deformation process, thereby improving the ductility of the original coating to match the ductility of the substrate material 3, so that the coating material exhibits excellent ductility and crack resistance when subjected to bending, stretching and other deformations.

[0071] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those who are familiar with the technology in this field can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A composite coating structure in which a low-ductility functional coating matches a high-ductility substrate, characterized in that: The composite coating structure is covered on the surface of a base material (3), and is a coating composed of a low-ductility material (1) and a high-ductility material (2). The low-ductility material (1) is an active material that performs a function. The low-ductility material (1) and the high-ductility material (2) form a network structure pattern distribution in the composite coating structure. The high-ductility material (2) constitutes the skeleton of the network structure, and the low-ductility material (1) is embedded in each unit body surrounded by the skeleton.

2. A composite coating structure of a low-ductility functional coating and a high-ductility substrate according to claim 1, characterized in that: The base material (3) comprises a metal or non-metal material with good ductility, wherein the metal material comprises a pure metal or an alloy, and the non-metal material comprises a polymer, a carbon nanomaterial or an inorganic compound.

3. The composite coating structure of a low-ductility functional coating and a high-ductility substrate according to claim 1, characterized in that: The low-ductility material (1) includes glass, ceramic or low-ductility carbon-based material.

4. The composite coating structure of a low-ductility functional coating and a high-ductility substrate according to claim 1, characterized in that: The highly ductile material (2) comprises metal, rubber or polymer.

5. The composite coating structure of a low-ductility functional coating and a high-ductility substrate according to claim 1, characterized in that: The pattern includes a polygon composed of straight lines or a geometric shape surrounded by smooth curves, and the pattern is combined into a regular or irregular network structure.

6. The composite coating structure of a low-ductility functional coating and a high-ductility substrate according to claim 1, characterized in that: The mesh structure includes a honeycomb mesh structure, a chessboard mesh structure, a randomly distributed polygonal mesh structure or a bionic tissue mesh structure.

7. The composite coating structure of a low-ductility functional coating and a high-ductility substrate according to claim 1, characterized in that: The thickness ratio of the low-ductility material (1) to the high-ductility material (2) is (1-3):(1-3).

8. The composite coating structure of a low-ductility functional coating and a high-ductility substrate according to claim 1, characterized in that: The thickness of the low-ductility material (1) and the high-ductility material (2) are both 10 nm-100 μm.

9. The composite coating structure of a low-ductility functional coating and a high-ductility substrate according to claim 1, characterized in that: The ratio of the frame width of the high-ductility material (2) skeleton to the thickness of the high-ductility material (2) is (1-4):(1-2).

10. The composite coating structure of a low-ductility functional coating and a high-ductility substrate according to claim 1, characterized in that: The ratio of the inner frame length to the frame width of the high-ductility material (2) skeleton is (2-20):1.

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