An aluminum matrix composite material, a method for preparing the same, and an application thereof

Abstract

The application provides an aluminum-based composite material and a preparation method and application thereof. The aluminum-based composite material comprises a base material, a material of the base material comprising aluminum or an aluminum alloy; a micro-arc oxidation layer arranged on a surface of the base material, the micro-arc oxidation layer being prepared by a micro-arc oxidation method; and a ta-C thin film arranged on a surface of the micro-arc oxidation layer, the ta-C thin film being prepared by a physical vapor deposition technology and comprising a chromium layer, a tungsten carbide layer and a carbon layer arranged in sequence in a direction away from the micro-arc oxidation layer. The aluminum-based composite material has high hardness, wear resistance and corrosion resistance, and is not prone to deformation, and is suitable for application in high-speed and heavy-load working conditions.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy surface coating technology, specifically relating to an aluminum-based composite material, its preparation method, and its application. Background Technology

[0002] In recent years, with rapid economic growth, the demand for various materials has been increasing daily, especially lightweight, durable, and energy-saving materials. This demand has led to a year-on-year increase in aluminum alloy production. Starting in 1991, the global consumption of aluminum was 18.744 million tons, while my country's consumption was 8.68 million tons. By 2000, global aluminum consumption had grown to 24.7798 million tons, a ten-year growth rate of 32%; while my country's aluminum consumption increased by 3.5327 million tons, a growth rate more than three times. Aluminum is one of the most commonly used light metals and the second most abundant element in the Earth's crust. The density of pure aluminum is 2.7 g / cm³. 3 It has a relatively low specific gravity (approximately 2.7), which is 35% of that of iron and 30% of that of copper. Aluminum alloys are also one of the most widely used non-ferrous metal structural materials in industry. They are engineering alloys composed of aluminum as the base metal element and alloying elements and impurities. They are lightweight, low-cost, have excellent corrosion resistance, high thermal conductivity, and are recyclable, which gives them good formability, weldability, and machinability. They are widely used in the automotive, aerospace, and other industrial fields.

[0003] However, aluminum alloys, as structural materials, have drawbacks such as being soft, having poor wear resistance, poor corrosion resistance in special environments, and poor high-temperature resistance. Moreover, although aluminum alloys can spontaneously form an Al2O3 film in the air, the film is very thin and has many defects, making it unable to effectively protect the substrate.

[0004] Therefore, researchers typically employ surface modification methods such as micro-arc oxidation, anodic oxidation, chemical oxidation, plasma spraying, and vapor deposition to modify the surface of aluminum and aluminum alloys. Among these, micro-arc oxidation is a technique for in-situ growth of ceramic layers, offering advantages such as high production efficiency, stable processes, and good repeatability. However, existing micro-arc oxidation methods result in micro-arc oxide layers with relatively high surface roughness, low hardness, and poor wear resistance. Furthermore, the oxide film has a high porosity, which allows corrosive media to more easily penetrate the film and cause corrosion, leading to a high surface wear rate. Summary of the Invention

[0005] To solve all or part of the above-mentioned technical problems, the present invention provides the following technical solutions:

[0006] One objective of this invention is to provide an aluminum-based composite material, comprising:

[0007] The substrate, wherein the material of the substrate includes aluminum or aluminum alloy;

[0008] A micro-arc oxidation layer is disposed on the surface of the substrate, and the micro-arc oxidation layer is prepared by micro-arc oxidation method;

[0009] A ta-C thin film is disposed on the surface of the micro-arc oxidation layer. The ta-C thin film is prepared by physical vapor deposition and includes a chromium layer, a tungsten carbide layer and a carbon layer arranged sequentially in a direction away from the micro-arc oxidation layer.

[0010] This invention, by depositing the aforementioned ta-C film on a micro-arc oxidation layer, can significantly improve the material's hardness, wear resistance, and corrosion resistance. The sequentially arranged chromium, tungsten carbide, and carbon layers in the ta-C film provide a suitable hardness gradient. This appropriate hardness transition increases the bonding force between the three layers of the ta-C film, as well as the bonding force between the ta-C film and the micro-arc oxidation layer, thereby improving the composite material's toughness. The ta-C film can seal the micropores on the surface of the micro-arc oxidation layer, preventing corrosive media from entering through these pores and causing the ceramic film to detach, thus increasing the material's corrosion resistance. Furthermore, the aluminum-based composite material exhibits excellent deformation resistance, making it less prone to deformation and failure under high-speed, heavy-load conditions.

[0011] In some embodiments, the thickness ratio of the micro-arc oxidation layer to the ta-C film is 15-25:2.9-5.

[0012] In some embodiments, the thickness ratio of the chromium layer, the tungsten carbide layer, and the carbon layer is 600N1000:100~500:

[0013] 1200N3500.

[0014] In some embodiments, the thickness of the micro-arc oxidation layer is 15–25 μm, the thickness of the ta-C film is 2.9–5 μm, wherein the thickness of the chromium layer is 600–1000 nm, the thickness of the tungsten carbide layer is 100–500 nm, and the thickness of the carbon layer is 1.2–3.5 μm.

[0015] In some embodiments, the carbon layer is a hydrogen-free carbon layer. Compared to conventional carbon layers, the hydrogen-free carbon layer has superior toughness.

[0016] In some embodiments, the micro-arc oxidation layer is made of alumina ceramic, such as alumina ceramic materials with grades 2014, 2024, 5052, and 5083.

[0017] A second objective of this invention is to provide a method for preparing an aluminum-based composite material, comprising:

[0018] A substrate is provided, wherein the material of the substrate includes aluminum or an aluminum alloy;

[0019] A micro-arc oxidation layer is formed on the surface of the substrate using a micro-arc oxidation method;

[0020] A chromium layer, a tungsten carbide layer, and a carbon layer are sequentially deposited on the surface of the micro-arc oxide layer to form a ta-C thin film, thereby obtaining an aluminum-based composite material.

[0021] In some embodiments, the micro-arc oxidation method specifically includes: using the substrate as the anode, placing it together with the cathode in an electrolyte containing 20-40 g / L of silicate (e.g., alkaline silicate), and performing micro-arc oxidation treatment in a constant voltage mode; wherein the positive voltage is 500-550V, the negative voltage is 30-100V, the frequency is 400-600Hz, and the duty cycle is 10-30%.

[0022] In some embodiments, the micro-arc oxidation treatment time is 10 to 50 minutes.

[0023] In some embodiments, the temperature of the electrolyte is 20–70°C.

[0024] In some embodiments, the alkaline silicate includes one or a combination of sodium silicate, sodium metasilicate, potassium silicate, iron silicate, magnesium silicate, and calcium silicate.

[0025] In some embodiments, the electrolyte further includes 2–12 g / L of an alkaline pH adjuster to adjust the pH of the electrolyte to a weakly alkaline state. The alkaline pH adjuster includes, for example, sodium hydroxide and potassium hydroxide, but is not limited to these.

[0026] In some embodiments, the electrolyte further includes 2-15 g / L of a colorant for surface coloring of the aluminum-based composite material. The colorant may include, for example, one or more combinations of sodium metavanadate, copper sulfate, and copper carbonate, but is not limited thereto.

[0027] In some embodiments, the electrolyte further includes a surfactant of 2-5 g / L, such as sodium dodecyl sulfate and / or sodium fluoride, but is not limited thereto.

[0028] In some embodiments, the solvent of the electrolyte includes water.

[0029] In some embodiments, the cathode is made of stainless steel.

[0030] In some embodiments, the preparation method further includes etching and cleaning the substrate containing the micro-arc oxide layer before depositing the ta-C thin film. The etching and cleaning includes placing the substrate containing the micro-arc oxide layer in a physical vapor deposition reaction chamber and etching and cleaning it under conditions of vacuum degree ≤2×10-3Pa, temperature of 130~160℃, and bias voltage of -700~-900V, and then depositing the ta-C thin film.

[0031] In some embodiments, the physical vapor deposition technique specifically includes: under an argon atmosphere and a pressure of less than or equal to 1 Pa, a chromium layer and a tungsten carbide layer are deposited sequentially using a chromium target and a tungsten carbide target, respectively, wherein the deposition time of the chromium layer is 60 to 190 min, and the deposition time of the tungsten carbide layer is 350 to 440 min.

[0032] In some embodiments, the physical vapor deposition technique specifically includes: after the tungsten carbide layer is formed, adjusting the pressure of the argon atmosphere to less than or equal to 1.5 Pa and the vacuum degree to less than or equal to 3 × 10⁻⁶ Pa. -3 Pa, and adjust the temperature to 30-50℃, the multi-arc current to 100-115A, and the bias voltage to -750--900V, and use graphite target deposition for 800-1500min to form the carbon layer on the tungsten carbide layer. The carbon layer obtained by deposition is a hydrogen-free carbon layer.

[0033] In some embodiments, the preparation method further includes pretreating the substrate to remove surface contaminants before performing micro-arc oxidation. For example, the pretreatment includes polishing with 300# to 2000# sandpaper.

[0034] In some embodiments, the preparation method further includes: after the micro-arc oxidation is completed, the obtained material is first polished and cleaned, and then physical vapor deposition is performed.

[0035] In some embodiments, the preparation method further includes cleaning the substrate containing the micro-arc oxidation layer with organic reagents such as petroleum ether, acetone, and ethanol before etching and cleaning it to remove surface oil.

[0036] A third objective of this invention is to provide an aluminum-based composite material prepared by any one of the methods described herein.

[0037] The fourth objective of this invention is to provide the application of the aforementioned aluminum-based composite material in the manufacture of the moving or stationary discs of automotive air conditioning compressors. The resulting moving and stationary discs of automotive air conditioning compressors possess advantages such as low coefficient of friction, high load-bearing capacity, high COP (coefficient of performance), and good cooling and noise reduction effects.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] (1) The present invention provides the ta-C film on the micro-arc oxidation layer, which can significantly improve the hardness, wear resistance and corrosion resistance of the material, and has high bonding strength; the chromium layer, tungsten carbide layer and carbon layer arranged in sequence in the ta-C film can make the ta-C film as a whole have a suitable hardness gradient. The reasonable hardness transition can increase the bonding force between the three layers of the ta-C film, as well as the bonding force between the ta-C film as a whole and the micro-arc oxidation layer, and can also improve the toughness of the material.

[0040] (2) The aluminum-based composite material provided by the present invention has good corrosion resistance. The ta-C film can seal the tiny pores on the surface of the micro-arc oxidation layer, prevent the corrosive medium from entering through the pores and causing the ceramic film to fall off, thereby increasing the corrosion resistance of the material.

[0041] (3) The aluminum-based composite material provided by the present invention has good resistance to deformation, making it less prone to deformation and failure under high-speed and heavy-load conditions. It is particularly suitable for use in the preparation of components and equipment for high-speed and heavy-load conditions. The moving and stationary discs of the automotive air conditioning compressor prepared with it have advantages such as low friction coefficient, strong load-bearing capacity and large COP (energy efficiency ratio). Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a graph showing the friction coefficient of the aluminum-based composite material prepared in Example 1 of this invention;

[0044] Figure 2 This is a cross-sectional electron microscope image of the aluminum-based composite material prepared in Example 2 of the present invention;

[0045] Figure 3 This is a photograph of the thickness of the micro-arc oxide layer formed in Embodiment 3 of the present invention;

[0046] Figure 4 This is a graph showing the friction coefficient of the aluminum-based composite material prepared in Comparative Example 1 of the present invention;

[0047] Figure 5 This is a scanning electron microscope image of the micro-arc oxidation layer prepared in Comparative Example 1;

[0048] Figure 6These are surface hardness diagrams of the aluminum-based composite materials in Embodiment 2 and Comparative Example 2 of the present invention;

[0049] Figure 7 The turbine of the vehicle air conditioning compressor is made using the aluminum-based composite material described in Example 1 of this invention. Detailed Implementation

[0050] The technical solutions of the present invention will be described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention. The specific functional details disclosed herein should not be construed as limiting, but are merely intended to form the basis of the claims and to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0051] Unless otherwise specified, all raw materials and reagents used in this invention are commercially available.

[0052] The specific method for testing the friction and wear life in this invention is as follows: The friction and wear life of the aluminum-based composite material under atmospheric conditions is tested using a UMT-Tribolab multifunctional friction and wear testing machine. The specific method is as follows: [The text abruptly ends here, so the translation also ends here.] The alumina ball and the test sample were subjected to a reciprocating sliding mechanism with a sliding frequency of 5 Hz, a load of 5 N, an ambient temperature of (27±3) ℃, a relative humidity of (75±5)%, and an experimental time of 30 min.

[0053] The bonding strength of the aluminum-based composite material was measured using the Step 300NHT3 nanoindentation method. The bonding strength rating method involves applying a controllable load to the coating surface, pressing an indenter into the film, measuring the indentation depth in real time, and judging the coating bonding strength level by observing the cracking at the indentation edge. The specific steps are as follows:

[0054] The conical indenter of the Rockwell hardness tester (with a cone angle of 120° and a tip radius of 0.2 mm) is pressed into the coating surface under a certain test pressure. After holding for 6 seconds, the pressure is released, and the indenter will leave a conical indentation (marker) on the sample surface. The coating condition at the edge of the indentation is observed and compared with the crack judgment standard to determine the coating adhesion grade. The rating standard is divided into HF0 to HF6.

[0055] The method for measuring the load-bearing capacity of aluminum-based composite materials is as follows: apply a high load (contact stress > 1GP) to the surface of the aluminum alloy and observe the ease with which the film detaches. If the film does not detach, it indicates good load-bearing capacity; otherwise, it indicates poor load-bearing capacity.

[0056] Example 1

[0057] This embodiment uses the following method to perform composite treatment on the surface of a 6061 grade aluminum alloy substrate to prepare an aluminum-based composite material. The specific steps are as follows:

[0058] 1. Pre-treat the aluminum alloy surface by successively polishing it with 300#, 600#, 800#, 1000#, and 2000# fine sandpaper to remove surface dirt;

[0059] 2. Micro-arc oxidation treatment of pretreated aluminum alloy: Using the aluminum alloy as the anode and stainless steel as the cathode, the cathode and anode are placed together in a silicate electrolyte at a temperature of 20℃. The electrolyte uses deionized water as the solvent and contains 20 g / L sodium silicate, 2 g / L potassium hydroxide, 2 g / L sodium metavanadate, and 2 g / L sodium dodecyl sulfate. The micro-arc oxidation is performed in constant voltage mode, with a positive voltage of 500V, a negative voltage of 30V, a frequency of 400Hz, a duty cycle of 10%, and an oxidation time of 10 min, in order to form a micro-arc oxide layer on the surface of the aluminum alloy.

[0060] 3. After the above micro-arc oxidation is completed, the obtained composite material is ground and polished; then it is washed with alcohol and deionized water in sequence, and dried at room temperature for later use;

[0061] 4. Deposit ta-C thin films using PI series coating equipment, specifically including the following steps:

[0062] (4-1) Before deposition, the surface of the aluminum alloy material containing the micro-arc oxide layer is pretreated by placing it in petroleum ether to wipe it to remove surface oil, then placing it in acetone for ultrasonic cleaning for 30 minutes, then in anhydrous ethanol for ultrasonic cleaning for 15 minutes, and finally drying it in a clean vacuum oven.

[0063] (4-2) Using a PI series coating equipment manufactured by Anhui Chunyuan, equipped with a bent-tube electromagnetic filter system, a ta-C thin film is deposited. The material treated in step 4-1 is loaded into the vacuum chamber, the chamber door is closed, a vacuum is drawn, and the chamber is heated to a vacuum level of less than 2 × 10⁻⁶. -3 Pa, temperature reached 130℃, under a bias voltage of -750V, it was etched and cleaned to remove dust and other impurities attached to the surface, and the etching time was 80min.

[0064] (4-3) After etching is complete, Ar gas is introduced and the speed of the molecular pump is adjusted to control the gas pressure in the vacuum chamber at a certain level. ≤ 1 Pa; Turn on the Cr target (99.9% purity) to deposit a chromium layer for 160 min, then turn off the Cr target; Turn on the WC target to deposit a tungsten carbide layer for 350 min; After the tungsten carbide layer deposition is complete, adjust the Ar gas flow rate to control the deposition gas pressure at 0.8 Pa, and adjust the temperature inside the chamber to 30℃. When the vacuum degree is 1.5 × 10⁻⁶ Pa, the deposition pressure is controlled at 0.8 Pa.-3 At Pa, the multi-arc current is set to 100A and the bias voltage to -760V. The graphite target is turned on to deposit a carbon layer for 800 minutes. After deposition, the cavity is filled with protective argon gas, and the gas is released to atmospheric pressure. The cavity is opened and the furnace is removed. A ta-C thin film composed of a chromium layer, a tungsten carbide layer and a carbon layer is formed on the surface of the micro-arc oxide layer, thereby obtaining an aluminum-based composite material.

[0065] In this embodiment, the thickness of the micro-arc oxide layer is 15 μm, the thickness of the chromium layer is 600 nm, the thickness of the tungsten carbide layer is 100 nm, and the thickness of the carbon layer is 1.2 μm.

[0066] Figure 1 This is a graph showing the friction coefficient of the aluminum-based composite material prepared in Example 1.

[0067] Example 2

[0068] This embodiment uses the following method to perform a composite treatment on the surface of a 2024 aluminum alloy substrate to prepare an aluminum-based composite material. The specific steps are as follows:

[0069] 1. Pre-treat the aluminum alloy surface by successively polishing it with 300#, 600#, 800#, 1000#, and 2000# fine sandpaper to remove surface dirt;

[0070] 2. Micro-arc oxidation treatment of pretreated aluminum alloy: Using the aluminum alloy as the anode and stainless steel as the cathode, the cathode and anode are placed together in an electrolyte at a temperature of 50°C. The electrolyte uses deionized water as the solvent and contains 25 g / L sodium silicate, 4 g / L potassium hydroxide, 4 g / L sodium metavanadate, and 3 g / L sodium dodecyl sulfate. The micro-arc oxidation is performed in constant voltage mode, with a positive voltage of 525V, a negative voltage of 70V, a frequency of 500Hz, a duty cycle of 20%, and an oxidation time of 30 min, in order to form a micro-arc oxide layer on the surface of the aluminum alloy.

[0071] 3. After the above micro-arc oxidation is completed, the obtained composite material is ground and polished; then it is washed with alcohol and deionized water in sequence, and dried at room temperature for later use;

[0072] 4. Deposit ta-C thin films using PI series coating equipment, specifically including the following steps:

[0073] (4-1) Before deposition, the surface of the aluminum alloy material containing the micro-arc oxide layer is pretreated by placing it in petroleum ether to wipe it to remove surface oil stains, then placing it in acetone for ultrasonic cleaning for 30 minutes, then in anhydrous ethanol for ultrasonic cleaning for 15 minutes, and finally drying it in a clean vacuum oven.

[0074] (4-2) Using a PI series coating equipment manufactured by Anhui Chunyuan, equipped with a bent-tube electromagnetic filter system, ta-C thin films are deposited. The material treated in step 4-1 is loaded into the vacuum chamber, the chamber door is closed, a vacuum is drawn, and heating is performed to achieve a vacuum level of 1×10⁻⁶. -3 Pa, temperature up to 150℃, under a bias voltage of -800V, it is etched and cleaned to remove dust and other impurities attached to the surface, and the etching time is 90min.

[0075] (4-3) After etching, Ar gas is introduced and the molecular pump speed is adjusted to control the gas pressure in the vacuum chamber at 0.8 Pa; the Cr target (with a purity of 99.9%) is turned on to deposit a chromium layer for 175 min, then the Cr target is turned off; the WC target is turned on to deposit a tungsten carbide layer for 400 min; after the tungsten carbide layer is deposited, the Ar gas flow rate is adjusted to control the deposition gas pressure at 1.2 Pa, and the temperature inside the chamber is adjusted to 140℃, with a vacuum degree of 2.8 × 10⁻⁶. -3 At Pa, the multi-arc current is set to 112A and the bias voltage is -850V. The graphite target is turned on to deposit a carbon layer for 1400min. After deposition, Ar gas is introduced into the cavity, and the gas is released to atmospheric pressure. The cavity is opened and the furnace is removed. A ta-C thin film composed of a chromium layer, a tungsten carbide layer and a carbon layer is formed on the surface of the micro-arc oxide layer, thereby obtaining an aluminum-based composite material.

[0076] In this embodiment, the thickness of the micro-arc oxide layer is 20 μm, the thickness of the chromium layer is 660 nm, the thickness of the tungsten carbide layer is 153 nm, and the thickness of the carbon layer is 3.3 μm. Figure 2 This is an electron microscope image of the cross-section of the aluminum-based composite material prepared in Example 2, showing the thickness of each layer, where the ta-C film is approximately 4.2 μm.

[0077] Example 3

[0078] In this embodiment, the surface of a 7075 aluminum alloy substrate is composite-treated using the following method to prepare an aluminum-based composite material. The specific steps are as follows:

[0079] 1. Pre-treat the aluminum alloy surface by successively polishing it with 300#, 600#, 800#, 1000#, and 2000# fine sandpaper to remove surface dirt;

[0080] 2. Micro-arc oxidation treatment of pretreated aluminum alloy: Using the aluminum alloy as the anode and stainless steel as the cathode, the cathode and anode are placed together in an electrolyte at a temperature of 70°C. The electrolyte uses deionized water as the solvent and contains 30 g / L sodium silicate, 5 g / L potassium hydroxide, 5 g / L sodium metavanadate, and 3 g / L sodium dodecyl sulfate. The micro-arc oxidation is performed in constant voltage mode, with a positive voltage of 550V, a negative voltage of 100V, a frequency of 600Hz, a duty cycle of 30%, and an oxidation time of 50 min, in order to form a micro-arc oxide layer on the surface of the aluminum alloy.

[0081] 3. After the above micro-arc oxidation is completed, the obtained composite material is ground and polished; then it is washed with alcohol and deionized water in sequence, and dried at room temperature for later use;

[0082] 4. Deposit ta-C thin films using PI series coating equipment, specifically including the following steps:

[0083] (4-1) Before deposition, the surface of the aluminum alloy material containing the micro-arc oxide layer is pretreated by placing it in petroleum ether to wipe it to remove surface oil stains, then placing it in acetone for ultrasonic cleaning for 30 minutes, then in anhydrous ethanol for ultrasonic cleaning for 15 minutes, and finally drying it in a clean vacuum oven.

[0084] (4-2) Using a PI series coating equipment manufactured by Anhui Chunyuan, equipped with a bent-tube electromagnetic filter system, ta-C thin films were deposited. The material treated in step 4-1 was loaded into the vacuum chamber, the chamber door was closed, a vacuum was drawn, and the chamber was heated to a vacuum degree of 1.5 × 10⁻⁶. -3 At a temperature of 160℃ and a bias voltage of -900V, the surface is etched and cleaned to remove dust and other impurities. The etching time is 100 minutes.

[0085] (4-3) After etching, Ar gas is introduced and the molecular pump speed is adjusted to control the gas pressure in the vacuum chamber at 0.9 Pa; the Cr target (99.9% purity) is turned on to deposit a chromium layer for 190 min, then the Cr target is turned off; the WC target is turned on to deposit a tungsten carbide layer for 440 min; after the tungsten carbide layer is deposited, the Ar gas flow rate is adjusted to control the deposition gas pressure at 0.3 Pa, and the temperature inside the chamber is adjusted to 350℃. When the vacuum degree is 8×10⁻⁶, Ar gas is introduced and the molecular pump speed is adjusted to control the deposition gas pressure at 0.3 Pa. -4 At Pa, the multi-arc current is set to 115A and the bias voltage is -900V. The graphite target is turned on to deposit a carbon layer for 1000min. After deposition, Ar gas is introduced into the cavity, the gas is released to atmospheric pressure, the cavity is opened and the furnace is removed. A ta-C thin film composed of a chromium layer, a tungsten carbide layer and a carbon layer is formed on the surface of the micro-arc oxide layer, thereby obtaining an aluminum-based composite material.

[0086] In this embodiment, the thickness of the micro-arc oxide layer is 21 μm, the thickness of the chromium layer is 700 nm, the thickness of the tungsten carbide layer is 230 nm, and the thickness of the carbon layer is 2.1 μm. Figure 3 This is a photograph showing the thickness of the micro-arc oxidation layer in the aluminum-based composite material prepared in this embodiment.

[0087] Example 4

[0088] Example 4 is basically the same as Example 1, except that the electrolyte used in Example 4 is: the electrolyte uses deionized water as solvent and contains 40 g / L sodium silicate, 12 g / L potassium hydroxide, 15 g / L sodium metavanadate and 5 g / L sodium dodecyl sulfate.

[0089] Example 5

[0090] The preparation methods of Example 5 and Example 1 are basically the same, except that in the aluminum-based composite material prepared in Example 5, the thickness of the micro-arc oxidation layer is 25 μm, the thickness of the chromium layer is 1000 nm, the thickness of the tungsten carbide layer is 500 nm, and the thickness of the carbon layer is 3.5 μm.

[0091] Comparative Example 1

[0092] The only difference between Comparative Example 1 and Example 1 is that the aluminum-based composite material provided in Comparative Example 1 only has a micro-arc oxidation layer, and the preparation method of the micro-arc oxidation layer is the same as that in Example 1.

[0093] Figure 4 The graph shows the friction coefficient of Comparative Example 1, where only a micro-arc oxide layer is formed on a 6061 substrate. The measured friction coefficient is 0.45. Figure 5 This is a scanning electron microscope image of the surface morphology of the micro-arc oxide film in Comparative Example 1.

[0094] Comparative Example 2

[0095] The only difference between Comparative Example 2 and Example 2 is that the aluminum-based composite material provided in Comparative Example 2 only has a micro-arc oxidation layer, and the preparation method of the micro-arc oxidation layer is the same as that in Example 2.

[0096] The hardness of Example 2 and Comparative Example 2 was determined using the continuous stiffness method on the MTS-Nano G200 nanometer indentation testing platform. Figure 6 The results show that the hardness of Example 2 and Comparative Example 2 are 2546 HV and 948 HV, respectively, indicating that the aluminum-based composite material structure of Example 2 can significantly improve the mechanical properties of the material.

[0097] Comparative Example 3

[0098] The only difference between Comparative Example 3 and Example 1 is that step (4-3) of Comparative Example 3 does not involve depositing a chromium layer; instead, a tungsten carbide layer and a carbon layer are deposited sequentially on the micro-arc oxide layer. The rest of the process is the same as in Example 1.

[0099] Comparative Example 4

[0100] The only difference between Comparative Example 4 and Example 1 is that step (4-3) of Comparative Example 4 does not involve depositing a tungsten carbide layer; instead, a chromium layer and a carbon layer are deposited sequentially on the micro-arc oxide layer. The rest of the procedures are the same as in Example 1.

[0101] Comparative Example 5

[0102] The only difference between Comparative Example 5 and Example 1 is that step (4-3) of Comparative Example 5 does not involve depositing a carbon layer; instead, a chromium layer and a tungsten carbide layer are deposited sequentially on the micro-arc oxide layer. The rest of the procedures are the same as in Example 1.

[0103] Comparative Example 6

[0104] The only difference between Comparative Example 6 and Example 1 is that micro-arc oxidation was not performed; instead, a ta-C film was directly deposited on a 6061 grade aluminum alloy substrate. The rest of the procedures were the same as in Example 1. It was found that directly depositing a ta-C film on the aluminum alloy surface was insufficient to support the film's performance under high-speed, heavy-load conditions due to the softness of the aluminum alloy and the relatively thin film deposited via PVD. Therefore, the substrate was prone to deformation and failure. This indicates that the micro-arc oxidation layer and the ta-C film in the composite material can jointly improve the performance of parts made from this composite material, effectively preventing failure of aluminum alloy parts under high-speed, heavy-load conditions.

[0105] Comparative Example 7

[0106] The only difference between Comparative Example 7 and Example 1 is that micro-arc oxidation technology was not used; instead, an oxide layer was formed on the aluminum substrate using anodizing. Then, a ta-C film was prepared using the same method as in Example 1. The specific steps for preparing the oxide layer by anodizing are described in "Li Ruocan, Duan Tigang, et al.: The Influence of Anodized Film and Micro-arc Oxidized Film on Seawater Corrosion and Mechanical Properties of 5A06 Aluminum Alloy".

[0107] Compared to anodizing, micro-arc oxidation can form a ceramic layer of tens or hundreds of micrometers on the metal surface. This ceramic layer not only overcomes the thin oxide film formed by anodizing, but also significantly improves corrosion resistance, wear resistance, electrical insulation, and decorative properties. The former is used for decoration, while the latter is more suitable for load-bearing applications. For example, the aluminum-based composite material provided by this invention is particularly suitable for manufacturing turbines for automotive air conditioning compressors. Figure 7 This is a photograph of the turbine of an automotive air conditioning compressor made from the aluminum-based composite material of Example 1.

[0108] The relevant properties of the aluminum-based composite materials obtained in the above embodiments and comparative examples were tested, and the test results are shown in Table 1.

[0109] Table 1. Relevant properties of aluminum-based composite materials obtained in the embodiments and comparative examples of the present invention.

[0110]

[0111]

[0112] This invention employs a surface composite treatment method combining micro-arc oxidation and physical vapor deposition. Micro-arc oxidation is used to prepare an oxide layer, and arc ion plating is used to prepare a ta-C film on its surface. The resulting composite material has the characteristics of high hardness, high bonding strength, and low wear. It also improves the surface structure of the substrate by micro-arc oxidation, which greatly enhances the surface performance of the aluminum substrate and thus effectively improves the overall performance and service life of the substrate.

[0113] All aspects, embodiments, features, and examples of this invention are to be regarded as illustrative in all respects and are not intended to limit the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0114] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0115] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. An aluminum-based composite material, characterized in that, include: The substrate is made of aluminum or an aluminum alloy; A micro-arc oxidation layer is disposed on the surface of the substrate, wherein the material of the micro-arc oxidation layer includes alumina ceramic, which is prepared by micro-arc oxidation method; A ta-C thin film is disposed on the surface of the micro-arc oxidation layer. The ta-C thin film is prepared by physical vapor deposition and includes a chromium layer, a tungsten carbide layer and a hydrogen-free carbon layer arranged sequentially in a direction away from the micro-arc oxidation layer. The thickness of the micro-arc oxidation layer is 15~25μm; the thickness of the ta-C film is 2.9~5μm, the thickness of the chromium layer in the ta-C film is 600~1000nm, the thickness of the tungsten carbide layer is 100~500nm, and the thickness of the hydrogen-free carbon layer is 1.2~3.5μm.

2. The method for preparing the aluminum-based composite material according to claim 1, characterized in that, include: A substrate is provided, wherein the material of the substrate includes aluminum or an aluminum alloy; A micro-arc oxidation layer is formed on the surface of the substrate using a micro-arc oxidation method; A physical vapor deposition technique was used to sequentially deposit a chromium layer, a tungsten carbide layer, and a hydrogen-free carbon layer on the surface of the micro-arc oxide layer to form a ta-C thin film, thereby obtaining an aluminum-based composite material. The process involves using PI series coating equipment manufactured by Anhui Chunyuan, equipped with a bent-tube electromagnetic filtration system, to deposit the hydrogen-free carbon layer. Specifically, this includes adjusting the argon gas flow rate to control the deposition gas pressure to less than or equal to 1.5 Pa, adjusting the chamber temperature to 30-50°C, and ensuring a vacuum degree of less than or equal to 3 × 10⁻⁶. -3 Pa, with a multi-arc current of 100~115A and a bias voltage of -750~-900V, is used to deposit a hydrogen-free carbon layer on the tungsten carbide layer.

3. The preparation method according to claim 2, characterized in that, The micro-arc oxidation method specifically includes: using the substrate as the anode, placing it together with the cathode in an electrolyte containing 20~40g / L silicate, and performing micro-arc oxidation treatment in a constant voltage mode; wherein the positive voltage is 500~550V, the negative voltage is 30~100V, the frequency is 400~600Hz, and the duty cycle is 10~30%.

4. The preparation method according to claim 3, characterized in that: The micro-arc oxidation treatment time is 10~50 min.

5. The preparation method according to claim 3, characterized in that: The temperature of the electrolyte is 20~70℃.

6. The preparation method according to claim 3, characterized in that: The silicate includes one or a combination of sodium silicate, sodium metasilicate, and potassium silicate.

7. The preparation method according to claim 3, characterized in that: The electrolyte also includes 2-12 g / L of alkaline pH adjuster, 2-15 g / L of colorant, and 2-5 g / L of surfactant.

8. The preparation method according to claim 7, characterized in that: The alkaline pH adjuster includes sodium hydroxide and / or potassium hydroxide, the colorant is sodium metavanadate, and the surfactant is sodium dodecyl sulfate.

9. The preparation method according to claim 3, characterized in that: The cathode is made of stainless steel.

10. The preparation method according to claim 2, characterized in that: Before depositing the ta-C thin film, the substrate containing the micro-arc oxide layer is etched and cleaned. The etching and cleaning includes: placing the substrate containing the micro-arc oxide layer in a physical vapor deposition reaction chamber, and etching it under a vacuum of ≤2×10⁻⁶. -3 The etching and cleaning process is carried out under the conditions of Pa, temperature of 130~160℃, and bias voltage of -700~-900V, and then the ta-C thin film is deposited.

11. The preparation method according to claim 2, characterized in that, The physical vapor deposition technique specifically includes: under an argon atmosphere and a pressure of less than or equal to 1 Pa, a chromium target and a tungsten carbide target are used to deposit chromium and tungsten carbide layers respectively, wherein the deposition time of the chromium layer is 60-190 min and the deposition time of the tungsten carbide layer is 350-440 min.

12. The application of the aluminum-based composite material according to claim 1 in the preparation of the moving or stationary disc of an automotive air conditioning compressor.

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