A microwave absorbing laser cladding coating and its preparation method and application

Abstract

The present invention discloses a microwave absorbing laser cladding coating and a preparation method and application thereof. The microwave absorbing laser cladding coating is obtained on the surface of a substrate by laser cladding treatment of a metal-ceramic material, wherein the metal-ceramic material comprises the following components calculated by mass percentage: 98.5-48.5% nickel-based alloy, 10-50% aluminum nitride and 1.5% nickel-plated multi-walled carbon nanotubes; the microwave absorbing laser cladding coating has a core-shell structure, and the core-shell structure comprises aluminum nitride as a core structure and titanium nitride as a shell structure. The microwave absorbing laser cladding coating of the present invention has good microwave absorption performance in the range of 12.4-18 GHz.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave absorbing coatings, and in particular relates to a microwave absorbing laser cladding coating and a preparation method and application thereof. Background Art

[0002] As a form of energy, electromagnetic waves can carry various information and be used in wireless communications, satellite signals, remote control, positioning, navigation and other fields. They can also release energy directly and be used in the medical field, or as a carrier of energy transmission and used in the field of microwave power transmission. The widespread application of electromagnetic waves has brought convenience to our lives, but it has also caused increasingly serious electromagnetic pollution, which has had an adverse effect on people's health and the normal operation of electronic equipment. Absorbing materials can convert incident electromagnetic wave energy into other forms of energy to achieve the effect of absorbing electromagnetic waves. They not only have the function of electromagnetic protection, but also have bright application prospects in the field of electromagnetic radiation energy recovery. Traditional absorbing materials have shortcomings in rapid preparation, bonding strength and corrosion resistance. Therefore, exploring a rapid manufacturing method for absorbing materials with strong bonding strength and excellent corrosion resistance is of great significance for preventing electromagnetic radiation and protecting physical health. Summary of the invention

[0003] The main purpose of the present invention is to provide a microwave absorbing laser cladding coating and a preparation method and application thereof, so as to overcome the shortcomings of the prior art.

[0004] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0005] An embodiment of the present invention provides a microwave absorbing laser cladding coating, which is obtained on the surface of a substrate by laser cladding treatment of a metal-ceramic material, wherein the metal-ceramic material includes the following components calculated by mass percentage: 98.5-48.5% nickel-based alloy, 10-50% aluminum nitride and 1.5% nickel-plated multi-walled carbon nanotubes; the microwave absorbing laser cladding coating has a core-shell structure, and the core-shell structure includes aluminum nitride as a core structure and titanium nitride as a shell structure.

[0006] The embodiment of the present invention further provides a method for preparing the aforementioned microwave absorbing laser cladding coating, which comprises:

[0007] providing a substrate;

[0008] The nickel-based alloy, aluminum nitride and nickel-plated multi-walled carbon nanotubes are uniformly mixed to obtain a metal-ceramic material;

[0009] Furthermore, the metal-ceramic material is clad on the surface of the substrate using ultra-high-speed laser cladding technology to obtain a microwave absorbing laser cladding coating.

[0010] The embodiment of the present invention also provides the use of the aforementioned microwave absorbing laser cladding coating in the field of microwave absorption.

[0011] The embodiment of the present invention also provides the use of the aforementioned method for preparing a microwave absorbing laser cladding coating in preparing a microwave absorbing coating on the surface of a curved part or a shaft part.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) The microwave absorbing laser cladding coating of the present invention is prepared by laser cladding process, which is metallurgically bonded to the substrate and has the advantages of high bonding strength, low dilution, small thermal deformation of the workpiece, small heat-affected zone, and high process stability. It can effectively solve the problem of easy peeling of traditional microwave absorbing coatings due to poor bonding strength;

[0014] (2) The preparation process of the microwave absorbing laser cladding coating of the present invention is simple, and the mechanical properties of the coating are excellent, which can meet the surface coating preparation requirements of different types of parts (such as curved parts or shaft parts);

[0015] (3) The microwave absorption performance of the laser cladding coating of the present invention reaches the commercial standard (<-10dB), and the minimum reflection loss of the coating reaches -13dB. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 Schematic diagram of the structure of a microwave absorbing laser cladding coating prepared in a typical embodiment of the present invention;

[0018] Figure 2a-2b This is a SEM image of the coating of the nickel-plated carbon nanotubes doped in Example 2 of the present invention and the carbon nanotubes doped in Comparative Example 1; DETAILED DESCRIPTION

[0019] In view of the defects of the prior art, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. The main method is to use laser cladding technology to prepare metal-ceramic composite absorbing coatings. The bonding strength of the coatings is greatly improved compared with the absorbing coatings planted by traditional methods. At the same time, the absorbing performance is relatively excellent.

[0020] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Specifically, as one aspect of the technical solution of the present invention, a microwave absorbing laser cladding coating is obtained on the surface of a substrate by laser cladding treatment of a metal-ceramic material, wherein the metal-ceramic material includes the following components calculated by mass percentage: 98.5-48.5% nickel-based alloy, 10-50% aluminum nitride and 1.5% nickel-plated multi-walled carbon nanotubes; the microwave absorbing laser cladding coating has a core-shell structure, and the core-shell structure includes aluminum nitride as a core structure and titanium nitride as a shell structure.

[0022] The absorbing material is composed of insulating material and absorbent. Due to the characteristics of laser cladding technology, the selection of materials is greatly limited, and the cladding ability and dielectric properties of the materials need to be considered. In the present invention, AlN has the advantages of low density, high strength, good heat resistance, high thermal conductivity, corrosion resistance, and good dielectric properties. It can provide better corrosion resistance for the material and also help the impedance control of the material; Ni-based alloy has the characteristics of high dielectric and high magnetic loss, providing more magnetic loss, while optimizing impedance matching, Ni-based alloy and AlN can directly react with each other, further enhancing the bonding strength of the material; the addition of nickel-plated multi-walled carbon nanotubes provides more conductive channels for the material, further enhancing the absorbing performance, and nickel plating on the surface of carbon nanotubes reduces the cracking sensitivity during the cladding process. In summary, Ni-based alloy, AlN and nickel-plated carbon nanotubes are selected as raw materials, and the microwave absorbing laser cladding coating prepared by laser cladding technology has excellent absorbing performance.

[0023] In some preferred embodiments, the nickel-based alloy has a particle size of 35 μm to 75 μm.

[0024] In some preferred embodiments, the aluminum nitride has a particle size of 15 μm to 60 μm.

[0025] In some preferred embodiments, the nickel-plated multi-walled carbon nanotubes have a diameter of 20-30 nm and a length of 10-30 nm.

[0026] In some preferred embodiments, the nickel content in the nickel-plated multi-walled carbon nanotubes is above 60 wt %.

[0027] In some preferred embodiments, the nickel in the nickel-plated multi-walled carbon nanotubes is uniformly distributed outside the diameter of the carbon nanotubes.

[0028] In some preferred embodiments, in the nickel-based alloy, Fe≤5.0wt%, Cr≤17wt%, Si≤4.50wt%, B≤2.70wt%, C≤0.70wt%, and Ni≥60wt%.

[0029] In some preferred embodiments, the microwave absorbing laser cladding coating has a thickness of 1.0 mm to 1.2 mm.

[0030] In some preferred embodiments, the real part of the dielectric constant of the microwave absorbing laser cladding coating is 25-50, and the imaginary part of the dielectric constant is 7-27.

[0031] In some preferred embodiments, the titanium nitride is formed in situ by partial dissolution of aluminum nitride with titanium in the substrate.

[0032] In some preferred embodiments, the material of the substrate includes TC4, but is not limited thereto.

[0033] Another aspect of the embodiments of the present invention further provides a method for preparing the aforementioned microwave absorbing laser cladding coating, which comprises:

[0034] providing a substrate;

[0035] The nickel-based alloy, aluminum nitride and nickel-plated multi-walled carbon nanotubes are uniformly mixed to obtain a metal-ceramic material;

[0036] Furthermore, the metal-ceramic material is clad on the surface of the substrate using ultra-high-speed laser cladding technology to obtain a microwave absorbing laser cladding coating.

[0037] Specifically, the schematic structural diagram of the microwave absorbing laser cladding coating prepared in the present invention is as follows Figure 1 shown.

[0038] In some preferred embodiments, the preparation method specifically includes: mixing nickel-based alloy, aluminum nitride and nickel-plated multi-walled carbon nanotubes and ball milling for 120-130 minutes at a ball milling speed of 200-250r / min to obtain a metal-ceramic material; wherein the grinding balls used are stainless steel grinding balls, and the mass ratio of the grinding balls to the sum of the nickel-based alloy, aluminum nitride and nickel-plated multi-walled carbon nanotubes is 1:5 to 2:5.

[0039] Furthermore, the mass ratio of the grinding balls to the sum of the nickel-based alloy, aluminum nitride, and nickel-plated multi-walled carbon nanotubes is any one of 1:5, 1.5:5, and 2:5.

[0040] In some preferred embodiments, the preparation method specifically includes: preheating the substrate to 250-350°C, and then using ultra-high-speed laser cladding technology to clad the metal-ceramic material on the surface of the substrate to obtain a microwave absorbing laser cladding coating; wherein the laser beam spot diameter used in the ultra-high-speed laser cladding technology is 2.0mm; the laser power is 0.8-1.0KW, the scanning speed is 10-20mm / s; the overlap rate is 50-60%; and the flow rate of the protective gas is 9-10L / min.

[0041] Further, the protective gas includes argon, but is not limited thereto.

[0042] In some preferred embodiments, the preparation method further comprises: before the cladding treatment, grinding and cleaning the substrate; wherein the cleaning treatment comprises: using ethanol to clean the surface of the substrate obtained by the grinding treatment, at least for removing grease and surface oxides.

[0043] In some preferred embodiments, the preparation method further comprises: before the cladding treatment, vacuum drying the metal-ceramic material in an environment of 60 to 80° C. for 8 to 10 hours.

[0044] In some preferred embodiments, the material of the substrate includes TC4, but is not limited thereto.

[0045] Additive manufacturing technology plays an increasingly important role in aerospace, biomedicine, electronic communications and other fields. It provides designers with a processing method that can realize rapid manufacturing of composite structures and open up innovative design space for designers. As a kind of additive technology, laser cladding technology has the characteristics of high energy, fast forming, fast cooling, wide selection of cladding powders, less heat input, small stress and deformation, high bonding strength, precise processing, small thermal damage to the substrate, and flexible manufacturing. Compared with other methods for preparing absorbing coatings, the coating prepared by laser cladding has fine grains, uniform microstructure and controllable thickness. The laser cladding process can also form a good metallurgical bond between the coating and the substrate, which can significantly improve its bonding strength. The present invention combines metals and ceramics through laser cladding technology, explores the composition and preparation method of laser cladding composite powders used in the field of absorbing coating technology, and the prepared metal-ceramic coating has good absorbing performance and excellent bonding strength and corrosion resistance.

[0046] Another aspect of the embodiments of the present invention further provides the use of the aforementioned microwave absorbing laser cladding coating in the field of microwave absorption.

[0047] For example, it can be used in the preparation of microwave absorbing materials that absorb microwaves at frequencies of 12.4 to 18 GHz.

[0048] Another aspect of the embodiments of the present invention further provides the use of the aforementioned method for preparing a microwave absorbing laser cladding coating in preparing a microwave absorbing coating on the surface of a curved part or a shaft part.

[0049] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and drawings. This embodiment is implemented on the premise of the technical solution of the invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0050] Unless otherwise specified, the experimental materials used in the following examples can be purchased from conventional biochemical reagent companies.

[0051] In the following embodiments, the nickel-based alloy is nickel 60 alloy, and the particle size is 35 μm-75 μm.

[0052] The particle size of aluminum nitride powder is 15μm-60μm.

[0053] The diameter of the nickel-plated multi-walled carbon nanotubes is 20-30 nm, the length is 10-30 nm, and the nickel content is ≥60 wt%.

[0054] The nickel-plated multi-walled carbon nanotubes used in the present invention were purchased from Beijing Dekedaojin Technology Co., Ltd.

[0055] The amounts used in the following examples are all percentages by mass.

[0056] Example 1

[0057] In this embodiment, the mass proportions of the components of the metal-ceramic powder are as follows: the nickel-based alloy powder accounts for 88.5%, the aluminum nitride powder accounts for 10%, and the nickel-plated multi-walled carbon nanotubes account for 1.5%.

[0058] The use of the above-mentioned metal-ceramic powder for laser cladding to prepare an absorbing coating comprises the following steps:

[0059] (1) The powder ratio is weighed using an electronic balance, stainless steel is used as grinding balls, the mass ratio of grinding balls to mixed powder is 1:5, the ball milling speed is 240 r / min, the ball milling time is 120 min, and the mixed powder is vacuum dried in a vacuum drying oven at 80° C. for 8 h to obtain a metal-ceramic powder with good fluidity.

[0060] (2) Use 220#, 400#, 800#, and 1000# sandpaper to polish the surface of the TC4 substrate to be clad, and use anhydrous ethanol to clean the polished surface of the substrate to remove grease and surface oxides.

[0061] (3) Preheat the TC4 substrate at a temperature of 300°C.

[0062] (4) Ultra-high-speed laser cladding system is used for cladding, and the laser beam spot is The laser power was 1.0 KW, the scanning speed was 10 mm / s, the overlap rate was 50%, and the argon protective gas flow rate was 10 L / min.

[0063] Embodiment 2:

[0064] In this embodiment, the mass proportions of the components of the metal-ceramic powder are as follows: the nickel-based alloy powder accounts for 78.5%, the aluminum nitride powder accounts for 20%, and the nickel-plated multi-walled carbon nanotubes account for 1.5%.

[0065] The use of the above-mentioned metal-ceramic powder for laser cladding to prepare an absorbing coating comprises the following steps:

[0066] (1) The powder ratio is weighed using an electronic balance, stainless steel is used as grinding balls, the mass ratio of grinding balls to mixed powder is 1:5, the ball milling speed is 240 r / min, the ball milling time is 120 min, and the mixed powder is vacuum dried in a vacuum drying oven at 80° C. for 8 h to obtain a metal-ceramic powder with good fluidity.

[0067] (2) Use 220#, 400#, 800#, and 1000# sandpaper to polish the surface of the TC4 substrate to be clad, and use anhydrous ethanol to clean the polished surface of the substrate to remove grease and surface oxides.

[0068] (3) Preheat the TC4 substrate at a temperature of 300°C.

[0069] (4) Ultra-high-speed laser cladding system is used for cladding, and the laser beam spot is The laser power was 1.0 KW, the scanning speed was 10 mm / s, the overlap rate was 50%, and the argon protective gas flow rate was 10 L / min.

[0070] Embodiment 3:

[0071] In this embodiment, the mass proportions of the components of the metal-ceramic powder are as follows: the nickel-based alloy powder accounts for 68.5%, the aluminum nitride powder accounts for 30%, and the nickel-plated multi-walled carbon nanotubes account for 1.5%.

[0072] The use of the above-mentioned metal-ceramic powder for laser cladding to prepare an absorbing coating comprises the following steps:

[0073] (1) The powder ratio is weighed using an electronic balance, stainless steel is used as grinding balls, the mass ratio of grinding balls to mixed powder is 1:5, the ball milling speed is 240 r / min, the ball milling time is 120 min, and the mixed powder is vacuum dried in a vacuum drying oven at 80° C. for 8 h to obtain a metal-ceramic powder with good fluidity.

[0074] (2) Use 220#, 400#, 800#, and 1000# sandpaper to polish the surface of the TC4 substrate to be clad, and use anhydrous ethanol to clean the polished surface of the substrate to remove grease and surface oxides.

[0075] (3) Preheat the TC4 substrate at a temperature of 300°C.

[0076] (4) Ultra-high-speed laser cladding system is used for cladding, and the laser beam spot is The laser power was 1.0 KW, the scanning speed was 10 mm / s, the overlap rate was 50%, and the argon protective gas flow rate was 10 L / min.

[0077] Embodiment 4:

[0078] In this embodiment, the mass proportions of the components of the metal-ceramic powder are as follows: the nickel-based alloy powder accounts for 58.5%, the aluminum nitride powder accounts for 40%, and the nickel-plated multi-walled carbon nanotubes account for 1.5%.

[0079] The use of the above-mentioned metal-ceramic powder for laser cladding to prepare an absorbing coating comprises the following steps:

[0080] (1) The powder ratio is weighed using an electronic balance, stainless steel is used as grinding balls, the mass ratio of grinding balls to mixed powder is 1:5, the ball milling speed is 240 r / min, the ball milling time is 120 min, and the mixed powder is vacuum dried in a vacuum drying oven at 80° C. for 8 h to obtain a metal-ceramic powder with good fluidity.

[0081] (2) Use 220#, 400#, 800#, and 1000# sandpaper to polish the surface of the TC4 substrate to be clad, and use anhydrous ethanol to clean the polished surface of the substrate to remove grease and surface oxides.

[0082] (3) Preheat the TC4 substrate at a temperature of 300°C.

[0083] (4) Ultra-high-speed laser cladding system is used for cladding, and the laser beam spot is The laser power was 1.0 KW, the scanning speed was 10 mm / s, the overlap rate was 50%, and the argon protective gas flow rate was 10 L / min.

[0084] Embodiment 5:

[0085] In this embodiment, the mass proportions of the components of the metal-ceramic powder are as follows: the nickel-based alloy powder accounts for 48.5%, the aluminum nitride powder accounts for 50%, and the nickel-plated multi-walled carbon nanotubes account for 1.5%.

[0086] The use of the above-mentioned metal-ceramic powder for laser cladding to prepare an absorbing coating comprises the following steps:

[0087] (1) The powder ratio is weighed using an electronic balance, stainless steel is used as grinding balls, the mass ratio of grinding balls to mixed powder is 1:5, the ball milling speed is 240 r / min, the ball milling time is 120 min, and the mixed powder is vacuum dried in a vacuum drying oven at 80° C. for 8 h to obtain a metal-ceramic powder with good fluidity.

[0088] (2) Use 220#, 400#, 800#, and 1000# sandpaper to polish the surface of the TC4 substrate to be clad, and use anhydrous ethanol to clean the polished surface of the substrate to remove grease and surface oxides.

[0089] (3) Preheat the TC4 substrate at a temperature of 300°C.

[0090] (4) Ultra-high-speed laser cladding system is used for cladding, and the laser beam spot is The laser power was 1.0 KW, the scanning speed was 10 mm / s, the overlap rate was 50%, and the argon protective gas flow rate was 10 L / min.

[0091] Example 6

[0092] In this embodiment, the mass proportions of the components of the metal-ceramic powder are as follows: the nickel-based alloy powder accounts for 88.5%, the aluminum nitride powder accounts for 10%, and the nickel-plated multi-walled carbon nanotubes account for 1.5%.

[0093] The use of the above-mentioned metal-ceramic powder for laser cladding to prepare an absorbing coating comprises the following steps:

[0094] (1) The powder ratio is weighed using an electronic balance, stainless steel is used as grinding balls, the mass ratio of grinding balls to mixed powder is 1:5, the ball milling speed is 240 r / min, the ball milling time is 120 min, and the mixed powder is vacuum dried in a vacuum drying oven at 80° C. for 8 h to obtain a metal-ceramic powder with good fluidity.

[0095] (2) Use 220#, 400#, 800#, and 1000# sandpaper to polish the surface of the TC4 substrate to be clad, and use anhydrous ethanol to clean the polished surface of the substrate to remove grease and surface oxides.

[0096] (3) Preheat the TC4 substrate at a temperature of 300°C.

[0097] (4) Ultra-high-speed laser cladding system is used for cladding, and the laser beam spot is The laser power was 0.8 KW, the scanning speed was 10 mm / s, the overlap rate was 50%, and the argon protective gas flow rate was 10 L / min.

[0098] Example 7

[0099] In this embodiment, the mass proportions of the components of the metal-ceramic powder are as follows: the nickel-based alloy powder accounts for 88.5%, the aluminum nitride powder accounts for 10%, and the nickel-plated multi-walled carbon nanotubes account for 1.5%.

[0100] The use of the above-mentioned metal-ceramic powder for laser cladding to prepare an absorbing coating comprises the following steps:

[0101] (1) The powder ratio is weighed using an electronic balance, stainless steel is used as grinding balls, the mass ratio of grinding balls to mixed powder is 1:5, the ball milling speed is 240 r / min, the ball milling time is 120 min, and the mixed powder is vacuum dried in a vacuum drying oven at 80° C. for 8 h to obtain a metal-ceramic powder with good fluidity.

[0102] (2) Use 220#, 400#, 800#, and 1000# sandpaper to polish the surface of the TC4 substrate to be clad, and use anhydrous ethanol to clean the polished surface of the substrate to remove grease and surface oxides.

[0103] (3) Preheat the TC4 substrate at a temperature of 300°C.

[0104] (4) Ultra-high-speed laser cladding system is used for cladding, and the laser beam spot is The laser power was 1.0 KW, the scanning speed was 20 mm / s, the overlap rate was 50%, and the argon protective gas flow rate was 10 L / min.

[0105] Comparative Example 1:

[0106] In this comparative example, the mass proportions of the components of the metal-ceramic powder are as follows: the nickel-based alloy powder accounts for 98.5%, the aluminum nitride powder accounts for 0%, and the nickel-plated multi-walled carbon nanotubes account for 1.5%.

[0107] The use of the above-mentioned metal-ceramic powder for laser cladding to prepare an absorbing coating comprises the following steps:

[0108] (1) The powder ratio is weighed using an electronic balance, stainless steel is used as grinding balls, the mass ratio of grinding balls to mixed powder is 1:5, the ball milling speed is 240 r / min, the ball milling time is 120 min, and the mixed powder is vacuum dried in a vacuum drying oven at 80° C. for 8 h to obtain a metal-ceramic powder with good fluidity.

[0109] (2) Use 220#, 400#, 800#, and 1000# sandpaper to polish the surface of the TC4 substrate to be clad, and use anhydrous ethanol to clean the polished surface of the substrate to remove grease and surface oxides.

[0110] (3) Preheat the TC4 substrate at a temperature of 300°C.

[0111] (4) Ultra-high-speed laser cladding system is used for cladding, and the laser beam spot is The laser power is 1.0KW, the scanning speed is 10mm / s; the powder feeding rate is 20g / min; the overlap rate is 50%, and the argon protective gas flow rate is 10L / min.

[0112] Example Performance Test Standards and Methods

[0113] Hardness test: using Vickers hardness tester, model HV-1000, test force 200g.

[0114] Corrosion test: tested using Chenhua electrochemical workstation (CHI 660).

[0115] Reflection loss test: using vector network analysis and waveguide method, the test range is 12.4-18GHz, the sample size is 15.9*8.03mm, and the thickness is 2mm.

[0116] Comparative Example 2:

[0117] Same as Example 1, except that nickel-plated multi-walled carbon nanotubes are missing; the nickel-based alloy powder accounts for 90wt%, and the aluminum nitride powder accounts for 10wt%.

[0118] Comparative Example 3:

[0119] Same as Example 1, except that the nickel-plated multi-walled carbon nanotubes are replaced with equivalent nickel and multi-walled carbon nanotubes.

[0120] Comparative Example 4:

[0121] Same as Example 1, except that the amount of nickel-plated multi-walled carbon nanotubes used is 2 wt %.

[0122] Comparative Example 5:

[0123] Same as Example 1, except that the amount of nickel-plated multi-walled carbon nanotubes used is 0.5 wt %.

[0124] Table 1: Hardness and reflection loss test results of examples and comparative examples

[0125]

[0126]

[0127] Table 2: Electrochemical test results of some examples and comparative examples

[0128] name Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 <![CDATA[E corr / V]]> -0.19 -0.31 -0.33 -0.35 -0.38 -0.42 <![CDATA[I corr / A / cm 2 ]]> <![CDATA[8.52×10 -8 A]]> <![CDATA[6.54×10 -7 ]]> <![CDATA[8.53×10 -7 ]]> <![CDATA[7.40×10 -6 ]]> <![CDATA[6.54×10 -6 ]]> <![CDATA[1.22×10 -6 ]]>

[0129] It can be seen from Table 1 that by comparing the hardness and absorbing performance of the cladding layer of the comparative example with that of the embodiment, it is found that under the metal-ceramic powder composition and preparation method given in the present invention: the hardness of the coating in the embodiment is significantly improved, and the reflection loss of Example 2 at 13.8 GHz is -13.2 dB, which is significantly improved compared with comparative examples 1-5, and an unexpected technical effect is achieved. Figure 2a and Figure 2b is a SEM image of the coating of the nickel-plated carbon nanotubes doped in Example 2 of the present invention and the carbon nanotubes doped in Comparative Example 1. Figure 2a and Figure 2b It can be seen that nickel-plated carbon nanotubes reduce the generation of cracks in the coating compared to carbon nanotube doping. The addition of nickel increases the wettability of carbon nanotubes and metals and retains more carbon nanotubes under laser irradiation, preventing harmful ions from entering the coating, thereby improving the weather resistance of the coating and increasing the service life of the coating. In addition, the effective absorption bandwidth of nickel-plated carbon nanotubes is increased by 1GHz compared to carbon nanotubes, further improving the absorption performance. Figure 2a (Microwave absorbing laser cladding coating prepared in Example 2) It can be seen that a special core-shell structure is formed inside the coating, with unmelted aluminum nitride particles inside and titanium nitride particles on the outer layer. Due to the presence of unmelted aluminum nitride particles, the overall dielectric constant of the coating is adjusted (real part 25-50, imaginary part 7-27), making the impedance matching of the coating close to 1, allowing more electromagnetic waves to enter the coating for dissipation, thereby improving the coating's wave absorbing performance.

[0130] Table 2 shows the electrochemical test results of Example 2 and Comparative Examples 1-5. First, the cladding layer samples were processed into 10*10mm size by wire cutting, and the test samples were prepared by encapsulating with epoxy resin. The samples were placed in a pre-configured 3.5wt% sodium chloride electrolytic solution for measurement. The results show that the self-corrosion potential of Example 2 is -0.19V, and the self-corrosion current density is 8.52×10 -8 A / cm 2 The self-corrosion potential of comparative example 1 is -0.31 V, and the self-corrosion current density is 6.54×10 -7 A / cm 2 The self-corrosion potential of comparative example 2 is -0.33 V, and the self-corrosion current density is 8.53×10 -7 A / cm 2 The self-corrosion potential of comparative example 3 is -0.35 V, and the self-corrosion current density is 7.40×10 -6 A / cm 2 The self-corrosion potential of comparative example 4 is -0.38 V, and the self-corrosion current density is 6.54×10 -6 A / cm 2The self-corrosion potential of comparative example 5 is -0.42 V, and the self-corrosion current density is 1.22×10 - 6 A / cm 2 It is found that the self-corrosion current density of all comparative examples is higher than that of Example 2, and the corrosion potential of all comparative examples is lower than that of Example 2, indicating that the embodiments of the present invention have excellent corrosion resistance.

[0131] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0132] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical deformation made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the protection scope of the present invention.

Claims

1. A microwave absorbing laser cladding coating, characterized in that: The microwave absorbing laser cladding coating is obtained on the surface of a substrate by laser cladding treatment of a metal-ceramic material, wherein the metal-ceramic material comprises the following components calculated by mass percentage: 48.5-88.5% nickel-based alloy, 10-50% aluminum nitride and 1.5% nickel-plated multi-walled carbon nanotubes, and the sum of the percentages of the components in the metal-ceramic material is 100%; the microwave absorbing laser cladding coating has a core-shell structure, and the core-shell structure comprises aluminum nitride as a core structure and titanium nitride as a shell structure; the titanium nitride is formed in situ by partial dissolution of aluminum nitride and titanium element in the substrate.

2. The microwave absorbing laser cladding coating according to claim 1 is characterized in that: The particle size of the nickel-based alloy is 35 μm-75 μm.

3. The microwave absorbing laser cladding coating according to claim 1 is characterized in that: The particle size of aluminum nitride in the metal-ceramic material is 15 μm-60 μm.

4. The microwave absorbing laser cladding coating according to claim 1 is characterized in that: The nickel-plated multi-walled carbon nanotubes have a diameter of 20-30 nm and a length of 10-30 nm.

5. The microwave absorbing laser cladding coating according to claim 1 is characterized in that: The nickel content in the nickel-plated multi-walled carbon nanotubes is above 60wt%.

6. The microwave absorbing laser cladding coating according to claim 1 is characterized in that: The nickel in the nickel-plated multi-walled carbon nanotubes is evenly distributed outside the tube diameter of the carbon nanotubes.

7. The microwave absorbing laser cladding coating according to claim 1 is characterized in that: The thickness of the microwave absorbing laser cladding coating is 1.0 mm to 1.2 mm.

8. The microwave absorbing laser cladding coating according to claim 1 is characterized in that: The real part of the dielectric constant of the microwave absorbing laser cladding coating is 25-50, and the imaginary part of the dielectric constant is 7-27.

9. The microwave absorbing laser cladding coating according to claim 1, characterized in that: The material of the substrate includes TC4.

10. The method for preparing a microwave absorbing laser cladding coating according to any one of claims 1 to 9, characterized in that: include: providing a substrate; The nickel-based alloy, aluminum nitride and nickel-plated multi-walled carbon nanotubes are uniformly mixed to obtain a metal-ceramic material; Furthermore, the metal-ceramic material is clad on the surface of the substrate using ultra-high-speed laser cladding technology to obtain a microwave absorbing laser cladding coating.

11. The preparation method according to claim 10, characterized in that: Specifically include: A nickel-based alloy, aluminum nitride and nickel-plated multi-walled carbon nanotubes are mixed and ball-milled for 120-130 minutes at a ball-milling speed of 200-250 r / min to obtain a metal-ceramic material; wherein the grinding balls used are stainless steel grinding balls, and the mass ratio of the grinding balls to the sum of the nickel-based alloy, aluminum nitride and nickel-plated multi-walled carbon nanotubes is 1:5~2:

5.

12. The preparation method according to claim 10, characterized in that: Specifically include: The substrate is preheated to 250-350° C., and then the metal-ceramic material is clad on the surface of the substrate using ultra-high-speed laser cladding technology to obtain a microwave absorbing laser cladding coating; wherein the laser beam spot diameter used in the ultra-high-speed laser cladding technology is 2.0 mm, the laser power is 0.8-1.0 KW, the scanning speed is 10-20 mm / s, the overlap rate is 50-60%, and the flow rate of the protective gas is 9-10 L / min; the protective gas includes argon.

13. The preparation method according to claim 10, characterized in that: Also includes: Before the laser cladding treatment is performed, the substrate is firstly polished and cleaned; wherein the cleaning treatment comprises: using ethanol to clean the surface of the polished substrate, at least to remove grease and surface oxides.

14. The preparation method according to claim 10, characterized in that: Also includes: Before the cladding treatment, the metal-ceramic material is placed in an environment of 60-80° C. and vacuum dried for 8-10 hours.

15. Use of the microwave absorbing laser cladding coating according to any one of claims 1 to 9 in the field of microwave absorption.

16. The use according to claim 15, characterized in that: The application is the application of the microwave absorbing laser cladding coating in the preparation of microwave absorbing materials with microwave absorption frequencies of 12.4 to 18 GHz.

17. Use of the method for preparing a microwave absorbing laser cladding coating according to any one of claims 10 to 14 in preparing a microwave absorbing coating on a curved part surface.

18. Use of the method for preparing a microwave absorbing laser cladding coating according to any one of claims 10 to 14 in preparing a microwave absorbing coating on the surface of shaft parts.

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