Method for preparing metal-ceramic double-layer hollow sphere

Abstract

The invention discloses a method for preparing a metal-ceramic double-layer hollow sphere, which comprises the following steps of: 1, cleaning a ceramic hollow sphere, drying, sequentially cleaning the ceramic hollow sphere with absolute ethyl alcohol and deionized water, and drying in a vacuum drying oven, and 2, plating a metal layer on the surface of the ceramic hollow sphere, and after the pressure of the high-purity argon in the vacuum chamber reaches a target value, a metal target material serves as a sputtering source, sputtering current is adjusted to control the deposition rate, sputtering time is set to control the sputtering thickness, and the ceramic hollow balls are subjected to sputtering treatment. According to the method, through controllable sputtering parameters (sputtering current, sputtering time, working atmosphere pressure and the like), the surface of the spherical shell is uniformly covered with a metal layer (nickel, copper, aluminum, magnesium and various alloys), and the compactness of a coating layer and the metallurgical bonding strength of the coating layer and a base body are improved; meanwhile, the technological process is simplified, and the structural integrity of the hollow sphere cavity can be kept.

Description

Technical Field

[0001] The invention relates to the field of energy-absorbing material preparation, and in particular to a method for preparing metal-ceramic double-layer hollow spheres. Background Art

[0002] Metal-based composite foams combine lightweight and high strength, and have been widely used in aerospace structures, lightweight automotive components, and protective energy absorption systems. These materials consist of a metal matrix and randomly distributed hollow sphere fillers, which serve as a reinforcement. The size, wall thickness, and material composition of the hollow spheres directly influence the mechanical response and energy absorption efficiency of the foam.

[0003] Currently, hollow spheres are mainly divided into two categories: metal and ceramic. Metal hollow spheres have high strength and good plasticity, but their high density increases the overall weight of metal-based composite foam materials, limiting their lightweight advantages. Ceramic hollow spheres have low density and high hardness, which can improve the specific rigidity and initial yield strength of metal-based composite foam materials. However, the inherent brittleness of ceramic hollow spheres and the insufficient interfacial bonding between them and the metal matrix make them prone to interfacial debonding or spherical shell rupture under compression or impact loads, resulting in structural instability and reduced energy absorption efficiency.

[0004] To address these shortcomings, a metal layer is coated on the surface of the hollow ceramic sphere to form a metal-ceramic dual-phase interface, thereby improving the shell's crack resistance and interfacial bonding strength. This metal layer not only improves the crack propagation path at the microscopic level and enhances the shell's toughness, but also enhances the shear bearing capacity of the composite interface through metallurgical bonding, thereby optimizing the compressive stiffness and energy absorption properties of the metal-based composite foam under both static and dynamic loads.

[0005] However, existing metal coating technologies (such as electroplating, chemical deposition, thermal spraying, etc.) generally have problems such as uneven coating thickness, insufficient density, weak interface bonding, cumbersome process flow, and high cost investment. It is difficult to meet the uniformity and consistency requirements of hollow sphere fillers of high-performance metal-based composite foam materials in large-scale preparation and application.

[0006] Therefore, there is an urgent need to develop a technology for preparing metal-ceramic double-layer hollow spheres that is efficient, uniform, and has strong interfacial bonding. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for preparing metal-ceramic double-layer hollow spheres. This method achieves uniform coverage of the metal layer (nickel, copper, aluminum, magnesium and various alloys) on the surface of the sphere shell through controllable sputtering parameters (sputtering current, sputtering time, working atmosphere pressure, etc.), thereby improving the density of the coating layer and the metallurgical bonding strength with the substrate; at the same time, it simplifies the process flow, which is conducive to maintaining the structural integrity of the hollow sphere cavity.

[0008] In order to achieve the above object, the present invention provides the following technical solutions: A method for preparing metal-ceramic double-layer hollow spheres comprises the following steps: step 1, cleaning the hollow ceramic spheres and then drying them, washing the hollow ceramic spheres with anhydrous ethanol and deionized water in sequence, and then placing them in a vacuum drying oven for drying; step 2, coating the surface of the hollow ceramic spheres with a metal layer, and after the high-purity argon gas pressure in the vacuum chamber reaches a target value, using a metal target as a sputtering source, adjusting the sputtering current to control the deposition rate, and setting the sputtering time to control the sputtering thickness, and performing sputtering on the hollow ceramic spheres. Step 2 comprises: Step 21, Preparation Install the metal target at the target position of the coating machine, and evenly spread the ceramic hollow balls on the sample roller. After placement, close the vacuum chamber of the coating machine and start to evacuate the vacuum chamber. After the vacuum degree reaches the target value, introduce argon gas into the vacuum chamber. Step 22, Sputtering The target value of the argon gas pressure is 0.4 ~ 0.7 Pa, the sputtering current is a direct current, the sputtering current is 0.2 ~ 0.6A, and the sputtering time is 5 ~ 8 h. After the surface of the ceramic hollow sphere is completely sputtered, the sputtering current is turned off, the vacuum system is turned off, the vacuum chamber is vented to the atmosphere, and the vacuum chamber is opened to obtain a metal-ceramic double-layer hollow sphere.

[0009] Furthermore, in the above method for preparing metal-ceramic double-layer hollow spheres, step 1 comprises: Step 11: first place a ceramic hollow ball with a diameter of 3 to 5 mm in a beaker filled with anhydrous ethanol, place the beaker in an ultrasonic cleaner for ultrasonic cleaning, then place a ceramic hollow ball with a diameter of 3 to 5 mm in a beaker filled with deionized water, and place the beaker in an ultrasonic cleaner for ultrasonic cleaning. Step 12: Place the cleaned hollow ceramic balls in a vacuum drying oven for drying at a temperature of 50-80° C. for 110-140 minutes.

[0010] Furthermore, in the above method for preparing metal-ceramic double-layer hollow spheres, the washing time in anhydrous ethanol in step 11 is 9 to 12 minutes.

[0011] Furthermore, in the above method for preparing metal-ceramic double-layer hollow spheres, the washing time in deionized water in step 11 is 9 to 12 minutes.

[0012] Furthermore, in the above method for preparing metal-ceramic double-layer hollow spheres, in step 21, the target value of the vacuum degree is 3×10 -3 Pa, the flow rate of argon gas into the vacuum chamber is 40 ~ 70sccm.

[0013] Furthermore, in the above method for preparing metal-ceramic double-layer hollow spheres, the metal target material is one of nickel, copper, aluminum, magnesium and alloy target materials.

[0014] Furthermore, in the above method for preparing metal-ceramic double-layer hollow spheres, in step 2, the metal target material is pure aluminum, the argon gas pressure is 0.5 Pa, the sputtering current is 0.25 A, and the sputtering time is 6 h to obtain aluminum-ceramic double-layer hollow spheres.

[0015] Furthermore, in the above-mentioned method for preparing metal-ceramic double-layer hollow spheres, in step 2, the metal target material is pure nickel. When the argon pressure in the vacuum chamber reaches 0.5 Pa, the DC power supply of the pure nickel target material is turned on to start sputtering. The sputtering current is 0.3 A and the sputtering time is 6 h to obtain nickel-ceramic double-layer hollow spheres.

[0016] Furthermore, in the above method for preparing metal-ceramic double-layer hollow spheres, a PVD400 magnetron sputtering coating machine is used.

[0017] The metal-ceramic double-layer hollow spheres prepared by the magnetron sputtering technology in the present invention achieve nano-level uniform stacking and high density, effectively eliminate local weak areas, and strengthen the bonding effect between the metal layer and the ceramic hollow spheres; the low-temperature magnetron sputtering process suppresses microcracks caused by thermal stress, ensuring the geometric integrity and mechanical stability of the hollow sphere cavity; in addition, the DC magnetron sputtering process simplifies the pretreatment and post-processing steps, reduces energy consumption and operating costs, and has good mass production capabilities, providing a reliable process path for the industrial preparation of high-performance metal-based composite foam materials. DETAILED DESCRIPTION

[0018] The present invention will be described in detail below with reference to the embodiments. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

[0019] According to an embodiment of the present invention, a method for preparing a metal-ceramic double-layer hollow sphere is provided, wherein the metal includes nickel, copper, aluminum, magnesium and various alloys.

[0020] The preparation method comprises the following steps: Step 1: Clean and dry the ceramic hollow balls Specifically, the hollow ceramic balls are washed with anhydrous ethanol and deionized water in sequence and then placed in a vacuum drying oven for drying.

[0021] In step 11, a ceramic hollow ball with a diameter of 3 to 5 mm is placed in a beaker filled with anhydrous ethanol, and the beaker is placed in an ultrasonic cleaning apparatus for ultrasonic cleaning for 9 to 12 minutes.

[0022] Then, a ceramic hollow ball with a diameter of 3 to 5 mm was placed in a beaker filled with deionized water, and the beaker was placed in an ultrasonic cleaner for ultrasonic cleaning for 9 to 12 minutes.

[0023] Step 12: Place the cleaned hollow ceramic balls in a vacuum drying oven for drying at a temperature of 50-80° C. for 110-140 minutes.

[0024] Step 2: Coating the surface of the ceramic hollow sphere with a metal film Step 21, Preparation Use a PVD400 magnetron sputtering coating machine, install metal targets (such as nickel, copper, aluminum, magnesium and various alloy targets, which are the source of metal films) at the target position of the coating machine, and evenly spread the ceramic hollow balls on the sample roller. After placement, close the vacuum chamber of the coating machine and start evacuating the vacuum chamber. After the vacuum degree reaches the target value, introduce argon gas into the vacuum chamber with a purity of 99% to 99.99%.

[0025] The target vacuum degree is 3×10 -3 The flow rate of argon gas into the vacuum chamber is 40 ~ 70sccm.

[0026] Step 22, Sputtering After the high-purity argon gas pressure in the vacuum chamber reaches the target value, the metal target is used as the sputtering source, the sputtering current is adjusted to control the deposition rate, and the sputtering time is set to control the sputtering thickness, and the ceramic hollow spheres are sputtered.

[0027] The target value of argon gas pressure was 0.4 ~ 0.7 Pa, the sputtering current was direct current, the sputtering current was 0.2 ~ 0.6 A, and the sputtering time was 5 ~ 8 h.

[0028] The metal target material is pure aluminum, the argon gas pressure is 0.5 Pa, the sputtering current is 0.25 A, and the sputtering time is 6 h, which coats a layer of aluminum film on the surface of the ceramic hollow sphere.

[0029] The metal target material is pure nickel. When the argon pressure in the vacuum chamber reaches 0.5 Pa, the DC power supply of the pure nickel target material is turned on to start sputtering. The sputtering current is 0.3 A and the sputtering time is 6 h, and a layer of nickel film is coated on the surface of the ceramic hollow sphere.

[0030] After the surface of the ceramic hollow sphere is completely sputtered, the sputtering current is turned off, the vacuum system is turned off, the vacuum chamber is vented to the atmosphere, and the vacuum chamber is opened to obtain a metal-ceramic double-layer hollow sphere.

[0031] Example 1 A method for preparing nickel-ceramic double-layer hollow spheres by magnetron sputtering mainly comprises the following steps: Step 1: Place a ceramic hollow ball with a diameter of 3 to 5 mm in a beaker filled with anhydrous ethanol, place the beaker in an ultrasonic cleaner and ultrasonically clean it for 9 minutes, then place the cleaned ceramic hollow ball in a beaker filled with deionized water and clean it for 9 minutes, and dry the cleaned ceramic hollow ball in a vacuum drying oven for 110 minutes at a drying temperature of 50°C. Step 2: Coating is done using a PVD400 magnetron sputtering coating machine. The target material is installed at the target position of the coating machine. The ceramic hollow balls are evenly spread on the sample roller. After placement, the vacuum chamber of the coating machine is closed and the vacuum chamber is evacuated to a vacuum degree of 3×10 -3 Pa, when the vacuum degree reaches the target value, argon gas is introduced into the vacuum chamber at a flow rate of 40 sccm.

[0032] Step 3: When the argon pressure in the vacuum chamber reaches 0.5 Pa, the DC power supply of the pure nickel target is turned on to start sputtering. The sputtering current is 0.3 A and the sputtering time is 5 h.

[0033] Step 4: After the sputtering of the ceramic hollow spheres is completed, the sputtering current is turned off, the vacuum system is turned off, the vacuum chamber is ventilated to the atmosphere, and the vacuum chamber is opened to obtain nickel-ceramic double-layer hollow spheres.

[0034] In Example 2-4, the pure nickel target DC power supply is also connected in step 3. For other steps, please refer to Table 1.

[0035] Table 1 Specific parameters in each step of Examples 2-4 .

[0036] The nickel-ceramic double-layer hollow spheres prepared in Examples 1-4 were filled into an aluminum alloy matrix to prepare an aluminum-based composite foam material. Through quasi-static compression performance testing, it was found that compared with the aluminum-based composite foam material filled with only ceramic hollow spheres, the platform stress of the composite foam material filled with the nickel-ceramic double-layer hollow spheres prepared in Examples 1-4 was 134.35 MPa and the yield strength was 100.57 MPa. The composite foam filled with only ceramic hollow spheres was 109.84 MPa and 80.32 MPa, respectively, with the former increasing by about 22% and 25% respectively compared to the latter. Since other parameters are consistent, the performance improvement is mainly due to the strengthening effect of the nickel film. The nickel film not only enhances the bonding force between the ceramic hollow spheres and the aluminum alloy matrix, but also optimizes the stress distribution inside the material. Further studies have shown that as the sputtering time of the nickel-ceramic double-layer hollow spheres increases, the nickel film thickness gradually increases, and the platform stress and yield strength of the aluminum-based composite foam material will also gradually increase.

[0037] Example 5 A method for preparing aluminum-ceramic double-layer hollow spheres by magnetron sputtering, which differs from Example 1 in that: in step 3, the target material is pure aluminum, the argon gas pressure is 0.5 Pa, the sputtering current is 0.25 A, and the sputtering time is 5 h.

[0038] In Examples 6-8, the target material in step 3 is also pure aluminum. For other steps, please refer to Table 2.

[0039] Table 2 Specific parameters in each step of Examples 6-8 .

[0040] The aluminum-ceramic double-layer hollow spheres prepared in Examples 6-8 were filled into an aluminum alloy matrix to produce an aluminum-based composite foam material. Quasi-static compression test results showed that the composite foam material filled with the aluminum-ceramic double-layer hollow spheres prepared in Examples 6-8 had a platform stress of 121.89 MPa and a yield strength of 93.58 MPa, which were approximately 11% and 16% higher, respectively, than the composite foam material filled with only ceramic hollow spheres. As the aluminum film sputtering time increased during the preparation of the aluminum-ceramic double-layer hollow spheres, the platform stress and yield strength of the aluminum-based composite foam material also gradually increased. This shows that both nickel-ceramic double-layer hollow spheres and aluminum-ceramic double-layer hollow spheres share common characteristics in improving the compression performance of aluminum-based composite foam materials. That is, the introduction of the metal layer and the increase in thickness can effectively improve the material properties, providing a diversified metal coating option for optimizing the performance of metal-based composite foam materials.

[0041] Compared with the prior art, the present invention has the following beneficial effects: The metal-ceramic double-layer hollow spheres prepared by the magnetron sputtering technology in the present invention achieve nano-level uniform stacking and high density, effectively eliminate local weak areas, and strengthen the bonding effect between the metal layer and the ceramic hollow spheres; the low-temperature magnetron sputtering process suppresses microcracks caused by thermal stress, ensuring the geometric integrity and mechanical stability of the hollow sphere cavity; in addition, the DC magnetron sputtering process simplifies the pretreatment and post-processing steps, reduces energy consumption and operating costs, and has good mass production capabilities, providing a reliable process path for the industrial preparation of high-performance metal-based composite foam materials.

[0042] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing metal-ceramic double-layer hollow spheres, characterized in that: The steps include: Step 1: clean the hollow ceramic balls and then dry them. The ceramic hollow balls were washed with anhydrous ethanol and deionized water in turn and then placed in a vacuum drying oven for drying. Step 2: Plate a metal layer on the surface of the ceramic hollow sphere. After the high-purity argon gas pressure in the vacuum chamber reaches the target value, the metal target is used as the sputtering source, the sputtering current is adjusted to control the deposition rate, the sputtering time is set to control the sputtering thickness, and the ceramic hollow spheres are sputtered. Step 2 includes: Step 21, Preparation Install the metal target at the target position of the coating machine, and evenly spread the ceramic hollow balls on the sample roller. After placement, close the vacuum chamber of the coating machine and start to evacuate the vacuum chamber. After the vacuum degree reaches the target value, introduce argon gas into the vacuum chamber. Step 22, Sputtering The target value of argon gas pressure is 0.4~0.7Pa, the sputtering current is DC current, the sputtering current is 0.2~0.6A, and the sputtering time is 5~8h. After the surface of the ceramic hollow ball is completely sputtered, the sputtering current is turned off, the vacuum system is turned off, the vacuum chamber is vented to the atmosphere, and the vacuum chamber is opened to obtain a metal-ceramic double-layer hollow ball. In step 2, the metal target is pure aluminum, the sputtering current is 0.25A, and the sputtering time is 6h to obtain aluminum-ceramic double-layer hollow spheres. or, In step 2, the metal target material is pure nickel. When the air pressure in the vacuum chamber reaches 0.5 Pa, the DC power supply of the pure nickel target material is turned on to start sputtering. The sputtering current is 0.3 A and the sputtering time is 6 h to obtain nickel-ceramic double-layer hollow spheres.

2. The method for preparing metal-ceramic double-layer hollow spheres according to claim 1, characterized in that: Step 1 includes: Step 11: Place a ceramic hollow ball with a diameter of 3 to 5 mm in a beaker filled with anhydrous ethanol, and then place the beaker in an ultrasonic cleaning apparatus for ultrasonic cleaning. Then, a ceramic hollow ball with a diameter of 3-5 mm was placed in a beaker filled with deionized water, and the beaker was placed in an ultrasonic cleaning apparatus for ultrasonic cleaning. Step 12: Place the cleaned hollow ceramic balls in a vacuum drying oven for drying at a temperature of 50-80° C. for 110-140 minutes.

3. The method for preparing metal-ceramic double-layer hollow spheres according to claim 2, characterized in that: The washing time in anhydrous ethanol in step 11 is 9 to 12 minutes.

4. The method for preparing metal-ceramic double-layer hollow spheres according to claim 2, characterized in that: The washing time in deionized water in step 11 is 9 to 12 minutes.

5. The method for preparing metal-ceramic double-layer hollow spheres according to claim 1, characterized in that: In step 21, the target value of vacuum degree is 3×10 -3 Pa, the flow rate of argon gas into the vacuum chamber is 40~70sccm.

6. The method for preparing metal-ceramic double-layer hollow spheres according to claim 1, characterized in that: The metal target is one of nickel, copper, aluminum, magnesium and alloy targets.

7. The method for preparing metal-ceramic double-layer hollow spheres according to claim 1, characterized in that: PVD400 magnetron sputtering coating machine is used.