Aluminum-silicon alloy material and preparation method and application thereof

Abstract

The invention provides an aluminum-silicon alloy material and a preparation method and application thereof.The aluminum-silicon alloy material comprises an aluminum-silicon alloy base material and a composite layer existing on the surface of the aluminum-silicon alloy base material, and the composite layer comprises a nickel-phosphorus layer and a nickel particle layer existing between the nickel-phosphorus layer and the aluminum-silicon alloy base material; and the surface roughness of the aluminum-silicon alloy material is less than or equal to 0.7 mu m. According to the method, the surface roughness of the aluminum-silicon alloy material can be remarkably reduced, meanwhile, the corrosion resistance, wear resistance and other properties of the aluminum-silicon alloy material are improved, and the binding force of the composite layer and the aluminum-silicon alloy base material can be improved.

Description

[0001] This application claims priority to Chinese Patent Application No. 202410655037.1, filed on May 23, 2024, entitled “An aluminum-silicon alloy material and its preparation method and application”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of aluminum-silicon alloy materials, specifically to an aluminum-silicon alloy material, its preparation method, and its applications. Background Technology

[0003] Aluminum-silicon alloys are forging and casting alloy materials with aluminum and silicon as the main components. Due to their advantages such as light weight, good machinability, good thermal conductivity, and certain strength and hardness, they are widely used in aerospace, transportation, construction, automotive, and electronics industries. In particular, aluminum-silicon alloys can be used as heat dissipation materials and are widely used in components such as heat sinks in electronic devices.

[0004] However, due to limitations in the manufacturing process of aluminum-silicon alloys (aluminum-silicon alloy parts are usually made by die casting), their surface roughness is high, which affects the performance of aluminum-silicon alloys. For example, when aluminum-silicon alloys are used as heat dissipation materials in components such as heat sinks of electronic devices, the high surface roughness of the aluminum-silicon alloy material will lead to an increase in interfacial contact thermal resistance, affecting the heat dissipation performance of electronic devices.

[0005] Currently, polishing methods for aluminum alloys such as aluminum-silicon alloys mainly include chemical polishing, electrochemical polishing, and mechanical polishing. However, due to the low hardness, poor wear resistance, and poor corrosion resistance of aluminum-silicon alloys, these polishing methods have limited effect on improving the surface roughness of aluminum-silicon alloys. Even if the surface roughness of aluminum-silicon alloys can be reduced to a certain extent through long-term polishing, the poor wear resistance and corrosion resistance of aluminum-silicon alloys can easily cause the surface roughness of aluminum-silicon alloys to increase rapidly due to wear or corrosion.

[0006] Furthermore, after polishing aluminum-silicon alloys, depositing wear-resistant or corrosion-resistant layers on their surface to improve their wear resistance or corrosion resistance is still insufficient to effectively overcome the difficulty in polishing them. Meanwhile, depositing wear-resistant layers on the polished, low-roughness aluminum-silicon alloy surface results in weak adhesion between these layers and the alloy, leading to issues like peeling and detachment. This still fails to effectively address the high surface roughness, poor wear resistance, and poor corrosion resistance of aluminum-silicon alloys. Summary of the Invention

[0007] This invention provides an aluminum-silicon alloy material, its preparation method, and its application, which can reduce the surface roughness of the aluminum-silicon alloy material while improving its wear resistance, corrosion resistance, and the bonding strength between the composite layer and the aluminum-silicon alloy substrate.

[0008] In one aspect, the present invention provides an aluminum-silicon alloy material, comprising an aluminum-silicon alloy substrate and a composite layer present on the surface of the aluminum-silicon alloy substrate, the composite layer comprising a nickel-phosphorus layer and a nickel particle layer present between the nickel-phosphorus layer and the aluminum-silicon alloy substrate; the surface roughness of the aluminum-silicon alloy material is less than or equal to 0.7 μm.

[0009] According to one embodiment of the present invention, the surface roughness of the aluminum-silicon alloy material is less than or equal to 50 nm.

[0010] According to one embodiment of the present invention, the micro Vickers hardness of the aluminum-silicon alloy material is HV500 or higher.

[0011] According to one embodiment of the present invention, the bonding force between the composite layer and the aluminum-silicon alloy substrate is greater than or equal to 98%.

[0012] According to one embodiment of the present invention, the corrosion resistance of the aluminum-silicon alloy material satisfies the following condition: when the aluminum-silicon alloy material is subjected to a neutral salt spray test, the time at which corrosion begins to occur is greater than or equal to 120 hours.

[0013] According to one embodiment of the present invention, the nickel particle layer includes first nickel particles, the nickel-phosphorus layer includes second nickel particles, the particle size of the second nickel particles being larger than that of the first nickel particles; and / or, the nickel-phosphorus layer includes second nickel particles, the particle size of the second nickel particles being on the micrometer scale; and / or, the nickel particle layer includes first nickel particles, the particle size of the first nickel particles being 1 to 200 nm.

[0014] According to one embodiment of the present invention, the composite layer comprises nickel particles and nickel-phosphorus compounds; and / or, the mass percentage of phosphorus in the composite layer is 6% to 30%; and / or, the composite layer comprises a first region and a second region located on the side of the first region opposite to the aluminum-silicon alloy substrate, wherein the phosphorus content of the first region is less than the phosphorus content of the second region.

[0015] According to one embodiment of the present invention, the nickel particle layer includes gaps that expose the surface of the aluminum-silicon alloy substrate, and the nickel-phosphorus layer includes a covering portion that covers the nickel particle layer and a filling portion that fills the gaps in the nickel particle layer.

[0016] According to one embodiment of the present invention, the thickness of the composite layer is 5 to 50 μm; and / or, the ratio of the thickness of the composite layer to the thickness of the aluminum-silicon alloy substrate is (0.0005 to 0.1):1.

[0017] According to one embodiment of the present invention, the composite layer contains oil-based organic matter.

[0018] According to one embodiment of the present invention, the oil-based organic compound includes a perfluoropolyether with a molecular weight of 1000 to 4000.

[0019] In another aspect, the present invention provides a method for preparing the above-mentioned aluminum-silicon alloy material, comprising the following steps: subjecting an aluminum-silicon alloy substrate to a nickel immersion activation treatment, thereby forming a nickel particle layer on the surface of the aluminum-silicon alloy substrate through the nickel immersion activation treatment to obtain a first intermediate; subjecting the first intermediate to a chemical nickel-phosphorus plating treatment, thereby forming a nickel-phosphorus layer on the surface of the first intermediate through the chemical nickel-phosphorus plating treatment to obtain a second intermediate; polishing the surface of the nickel-phosphorus layer of the second intermediate to obtain a third intermediate; subjecting the third intermediate to a heat treatment to obtain a fourth intermediate; and subjecting the fourth intermediate to an oil immersion treatment to obtain the aluminum-silicon alloy material.

[0020] According to one embodiment of the present invention, the nickel immersion activation treatment is performed using an alkaline nickel immersion activation solution, wherein the pH value of the alkaline nickel immersion activation solution is ≥12; and / or, the alkaline nickel immersion activation solution includes a nickel source, the concentration of which is 40-80 g / L; and / or, the alkaline nickel immersion activation solution includes a pH buffer, the pH buffer being diammonium hydrogen phosphate and / or ammonium chloride; the concentration of the pH buffer in the alkaline nickel immersion activation solution is 50-100 g / L; and / or, the alkaline nickel immersion activation solution includes a corrosion inhibitor, the corrosion inhibitor being polyethylene glycol; the concentration of the corrosion inhibitor in the alkaline nickel immersion activation solution is 10-20 g / L; and / or, the conditions for the nickel immersion activation treatment are: a temperature of 30-50°C and a time of 40-300 s.

[0021] According to one embodiment of the present invention, the electroless nickel-phosphorus plating process includes: sequentially performing electroless nickel-phosphorus plating on the first intermediate using an alkaline electroless nickel-phosphorus plating solution and an acidic electroless nickel-phosphorus plating solution.

[0022] According to one embodiment of the present invention, the pH value of the alkaline electroless nickel-phosphorus plating solution is 10-11; and / or, the conditions for electroless nickel-phosphorus plating using the alkaline electroless nickel-phosphorus plating solution are: a temperature of 60-80°C and a deposition time of 0.5-1 h; and / or, the pH value of the acidic nickel-phosphorus plating solution is 4.5-5.0; and / or, the conditions for electroless nickel-phosphorus plating using the acidic electroless nickel-phosphorus plating solution are: a temperature of 80-90°C and a deposition time of 0.5-2 h.

[0023] According to one embodiment of the present invention, during the polishing process, a polishing wheel is used for polishing, wherein the polishing wheel is a cotton polishing wheel or a wool polishing wheel; and / or, the rotation speed of the polishing wheel is greater than 8000 rpm, and the polishing time is 0.5 to 2 min.

[0024] According to one embodiment of the present invention, the heat treatment is carried out in an atmospheric environment, and the temperature of the heat treatment is 200-350°C and the time is 2-3 hours.

[0025] According to one embodiment of the present invention, the oil immersion treatment is performed using an oil immersion solution comprising a perfluoropolyether with a molecular weight of 1000 to 4000; and / or, the oil immersion treatment is performed at a temperature of 20 to 40°C for a time of 24 to 48 hours.

[0026] In another aspect, the present invention provides a structural component comprising the above-described aluminum-silicon alloy material or an aluminum-silicon alloy material prepared according to the above-described preparation method.

[0027] In another aspect, the present invention provides an electronic device including the above-described structural components.

[0028] The aluminum-silicon alloy material, its preparation method, and its application provided by this invention form a composite layer on the surface of an aluminum-silicon alloy substrate, and a nickel particle layer exists between the nickel-phosphorus layer in the composite layer and the aluminum-silicon alloy substrate. The surface roughness of the aluminum-silicon alloy material is less than or equal to 0.7 μm. Compared with existing aluminum-silicon alloy materials, the surface roughness of the aluminum-silicon alloy material of this invention is significantly reduced. By forming the above-mentioned composite layer on the surface of the aluminum-silicon alloy material, the corrosion resistance and wear resistance of the aluminum-silicon alloy material can also be improved, and the bonding force between the composite layer and the aluminum-silicon alloy material can be significantly improved, avoiding phenomena such as peeling and detachment of the composite layer.

[0029] Therefore, this invention provides an aluminum-silicon alloy material that combines low surface roughness, high wear resistance, and high corrosion resistance. It can be applied in fields such as aerospace, transportation, construction, automobiles, and electronics. For example, it can be used as a heat dissipation material in components such as heat sinks of electronic devices. Due to the low surface roughness and other properties of this aluminum-silicon alloy material, it can reduce interfacial contact thermal resistance and improve the heat dissipation performance of electronic devices, which is of great significance for practical industrial applications. Attached Figure Description

[0030] Figure 1 This is a scanning electron microscope (SEM) image (microscopic image) of the nickel particle layer formed on the surface of the aluminum-silicon alloy substrate in Example 1;

[0031] Figure 2 This is a scanning electron microscope (SEM) image (microscopic image) of the nickel-phosphorus layer formed on the surface of the first intermediate in Example 1;

[0032] Figure 3 This is an optical microscope image of the bonding force between the composite layer and the aluminum-silicon alloy substrate tested by the cross-cut adhesion test in Example 1.

[0033] Figure 4 The image shows the X-ray diffraction (XRD) pattern of the composite layer on the surface of the aluminum-silicon alloy substrate in Example 1.

[0034] Figure 5 The image shows the energy dispersive X-ray spectrum of the composite layer on the surface of the aluminum-silicon alloy substrate in Example 1 (the horizontal axis represents energy, and the vertical axis represents peak intensity). Detailed Implementation

[0035] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This invention provides an aluminum-silicon alloy material, which includes an aluminum-silicon alloy substrate and a composite layer on the surface of the aluminum-silicon alloy substrate. The composite layer includes a nickel-phosphorus layer and a nickel particle layer between the nickel-phosphorus layer and the aluminum-silicon alloy substrate. The surface roughness of the aluminum-silicon alloy material is less than or equal to 0.7 μm.

[0037] The surface of the aluminum-silicon alloy material is also the side of the composite layer that faces away from the aluminum-silicon alloy substrate (and the side of the nickel-phosphorus layer that faces away from the aluminum-silicon alloy substrate), and the surface roughness of the aluminum-silicon alloy material is also the surface roughness of the composite layer (and the surface roughness of the nickel-phosphorus layer).

[0038] Generally, aluminum-silicon alloy substrates have composite layers on both sides of their thickness direction, so that the surface roughness of the aluminum-silicon alloy material on both sides of its thickness direction is less than or equal to 0.7μm.

[0039] For example, the surface roughness of the aluminum-silicon alloy material can be less than or equal to 0.6 μm, or less than or equal to 0.5 μm, or less than or equal to 0.4 μm, or less than or equal to 0.3 μm, or less than or equal to 0.2 μm, or less than or equal to 0.1 μm, or less than or equal to 50 nm.

[0040] In some embodiments, the surface roughness of the aluminum-silicon alloy material may be less than or equal to 45 nm, and may be more than or equal to 40 nm, for example, a range of 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or any two of these.

[0041] In this embodiment of the invention, the surface roughness of the aluminum-silicon alloy material described above can be tested using conventional instruments in the art, such as roughness testers.

[0042] In addition, the micro Vickers hardness of aluminum-silicon alloy materials can be HV500 or higher (i.e., higher than or equal to HV500), for example, HV500, HV550, HV600 or a range between any two of them.

[0043] In this embodiment of the invention, a conventional Vickers hardness tester in the art can be used to test the surface microhardness of aluminum-silicon alloy materials in order to measure the micro Vickers hardness of the aluminum-silicon alloy materials.

[0044] Furthermore, in the aforementioned aluminum-silicon alloy materials, the bonding force between the composite layer and the aluminum-silicon alloy substrate can be greater than or equal to 98%, for example, 98%, 99%, or 100%, exhibiting good bonding force. This can prevent phenomena such as peeling between the composite layer and the aluminum-silicon alloy substrate, thereby further ensuring the low surface roughness, wear resistance, and corrosion resistance properties of the aluminum-silicon alloy material.

[0045] In this embodiment of the invention, the bonding force between the composite layer and the aluminum-silicon alloy substrate can be detected by a cross-cut adhesion test, specifically by measuring the bonding force between the composite layer and the aluminum-silicon alloy substrate according to the ASTM D3359 standard.

[0046] Furthermore, the corrosion resistance of the aforementioned aluminum-silicon alloy materials meets the following requirements: In a neutral salt spray test, the time T for the aluminum-silicon alloy material to begin corrosion is greater than or equal to 120 hours. If no corrosion occurs within time T (T≥120 hours), the aluminum-silicon alloy material exhibits good corrosion resistance, further ensuring its chemical stability and low surface roughness.

[0047] In this embodiment of the invention, a neutral salt spray test can be performed on aluminum-silicon alloy materials according to the ASTM B117 standard to test the time T at which corrosion begins to appear.

[0048] The nickel particle layer includes multiple first nickel particles (elemental nickel particles), which are substantially uniformly dispersed on the surface of the aluminum-silicon alloy substrate (e.g., ...). Figure 1As shown, a nickel particle layer is formed. By first forming a nickel particle layer on the surface of the aluminum-silicon alloy, and then forming a nickel-phosphorus layer on the surface of the nickel particle layer, the bonding force between the composite layer formed by the nickel particle layer and the nickel-phosphorus layer and the aluminum-silicon alloy substrate can be effectively improved, and problems such as film peeling of the composite layer and / or the nickel-phosphorus layer can be avoided.

[0049] Typically, the nickel particle layer includes gaps (such as) exposed surfaces of the aluminum-silicon alloy substrate. Figure 1 As shown), specifically, the first nickel particles in the nickel particle layer are basically uniformly distributed on the surface of the aluminum-silicon alloy substrate. At least some of the first nickel particles have gaps between two adjacent first nickel particles (i.e., the two adjacent first nickel particles do not contact each other, thus forming gaps between the two adjacent first nickel particles). The multiple gaps formed in the nickel particle layer are basically uniformly distributed in the nickel particle layer.

[0050] The first nickel particles may include nano-sized nickel particles, that is, particles with a size of nanometers, which is beneficial to improving the bonding strength and other properties of the composite layer with the aluminum alloy substrate.

[0051] Generally, the smaller the particle size of the first nickel particles, the better it is to improve the bonding force between the composite layer and the aluminum alloy substrate. Therefore, it is preferable that the particle size of the first nickel particles is less than or equal to 200 nm.

[0052] In some embodiments, the particle size of the first nickel particles can be 1–230 nm, such as 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 80 nm, 100 nm, 120 nm, 150 nm, 170 nm, 200 nm, 230 nm, or any two of these. This is beneficial for improving the bonding strength between the composite layer and the aluminum alloy substrate, while also facilitating the formation of the nickel particle layer and simplifying the preparation process and conditions. According to the inventors' research, when the particle size of the first nickel particles exceeds 200 nm, it affects the bonding strength between the composite layer and the aluminum-silicon alloy substrate. As the particle size of the first nickel particles increases, the bonding strength between the composite layer and the aluminum-silicon alloy substrate tends to decrease. Therefore, a particle size of 1–200 nm for the first nickel particles is preferred, as it significantly improves the bonding strength and other properties of the composite layer with the aluminum-silicon alloy.

[0053] Specifically, the nickel particle layer can be formed by immersion nickel activation treatment on an aluminum-silicon alloy substrate. During the immersion nickel activation treatment, nickel ions in the immersion nickel activation solution react with elements such as aluminum in the aluminum-silicon alloy substrate through a displacement reaction to form nickel elemental particles (i.e., the first nickel particles) dispersed on the surface of the aluminum alloy substrate, thereby forming a nickel particle layer (or nickel activation layer) on the surface of the aluminum alloy substrate. The specific process and conditions of the immersion nickel activation treatment can be found in the relevant description of the preparation method of aluminum-silicon alloy materials below, and will not be elaborated further here.

[0054] Specifically, the nickel-phosphorus layer includes a covering portion covering the nickel particle layer and a filling portion filling the gaps in the nickel particle layer. That is, the nickel-phosphorus layer is located on the side of the nickel particle layer away from the aluminum-silicon alloy material and covers the nickel particle layer (covering the first nickel particles and gaps in the nickel particle layer). The covering portion covers the first nickel particles in the nickel particle layer and the filling portion of the nickel-phosphorus layer. The filling portion of the nickel-phosphorus layer is the part of the nickel-phosphorus layer that fills the gaps in the nickel particle layer. This filling portion is in contact with the aluminum-silicon alloy substrate.

[0055] Specifically, the thickness of the nickel-phosphorus layer and the thickness of the covering portion of the nickel-phosphorus layer are both greater than the thickness of the nickel particle layer. The thickness of the nickel particle layer can be in the nanometer range (the thickness of the nickel particle layer can be basically equal to the particle size of the first nickel particle in the nickel particle layer), the thickness of the nickel-phosphorus layer can be in the micrometer range, and the thickness of the covering portion of the nickel-phosphorus layer is also basically in the micrometer range.

[0056] Typically, a nickel-phosphorus layer consists of a second nickel particle (elemental nickel particles) and a nickel-phosphorus compound (nickel-phosphorus phase). The second nickel particle has a larger particle size than the first nickel particle, and can specifically be micrometer-sized nickel particles; the nickel-phosphorus compound is usually nanometer-sized (i.e., its particle size is in the nanometer range).

[0057] Specifically, the nickel-phosphorus layer comprises nickel (Ni) and phosphorus (P), with the mass percentage of nickel exceeding that of phosphorus. For example, the mass percentage of nickel in the nickel-phosphorus layer can be 70%, 75%, 80%, 85%, 90%, or any combination thereof, and the mass percentage of phosphorus can be 10%, 15%, 20%, 25%, 30%, or any combination thereof. The nickel in the nickel-phosphorus layer primarily exists as elemental nickel particles (secondary nickel particles), while the phosphorus primarily exists as nickel-phosphorus compounds (such as Ni3P).

[0058] Specifically, the composite layer includes nickel particles and nickel-phosphorus compounds, with the nickel particles comprising first nickel particles and second nickel particles. In the aforementioned aluminum-silicon alloy material, the composite layer is formed by a nickel particle layer and a nickel-phosphorus layer. The phosphorus element in the composite layer mainly originates from the nickel-phosphorus layer. In the composite layer, the phosphorus element mainly exists in the form of nickel-phosphorus compounds (such as Ni3P), while the nickel element mainly exists in the form of nickel particles (elemental nickel particles).

[0059] In practice, X-ray diffraction (XRD) analysis can be performed on the composite layer to determine the types of elements in the composite layer and their forms of existence.

[0060] Under normal circumstances, the mass percentage of phosphorus in the composite layer (the mass ratio of phosphorus in the composite layer to the composite layer) can be 6% to 30%.

[0061] In practice, energy-dispersive X-ray spectroscopy (EDS) analysis can be performed on composite layers and other films to obtain the mass percentage content of elements such as phosphorus (during EDS testing, the mass percentage content of each element in the constituent sample material (such as composite layers) is obtained based on the intensity of characteristic X-rays generated when the electron beam interacts with the material).

[0062] In addition, the composite layer may include a first region and a second region located on the side of the first region away from the aluminum-silicon alloy substrate, wherein the phosphorus content of the first region is less than that of the second region.

[0063] Specifically, the first region includes a nickel particle layer and a portion of the nickel-phosphorus layer near the nickel particle layer (the first sub-region), and the second region is the remaining portion of the nickel-phosphorus layer (the second sub-region). That is, the nickel-phosphorus layer includes the first sub-region near the nickel particle layer and the second sub-region located on the side of the first sub-region away from the nickel particle layer. The first sub-region is in contact with the nickel particle layer and forms the first region with the nickel particle layer, and the second sub-region is the second region.

[0064] Specifically, the nickel-phosphorus layer can be formed through a chemical nickel-phosphorus plating process. This involves chemically plating a nickel-phosphorus layer onto an aluminum alloy substrate (the first intermediate) with a nickel particle layer on its surface to form a nickel-phosphorus layer covering the nickel particle layer (or a chemically plated nickel-phosphorus layer). The process can begin by chemically plating the first intermediate with an alkaline solution (forming the first sub-region mentioned above), followed by chemically plating the first intermediate with an acidic solution (forming the second sub-region mentioned above). The specific process and conditions for chemical nickel-phosphorus plating are detailed in the following description of the preparation method for aluminum-silicon alloy materials, and will not be elaborated further here.

[0065] In this embodiment of the invention, the elemental or compositional composition of the above-mentioned nickel particle layer and nickel-phosphorus layer can be determined by X-ray diffraction (XRD) analysis, and the content of elements such as phosphorus in the film layer can be determined by EDS analysis.

[0066] In addition, the thickness of the composite layer can be 5 to 50 μm, for example, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or any combination thereof.

[0067] In addition, the ratio of the thickness of the composite layer to the thickness of the aluminum-silicon alloy substrate can be (0.0005 to 0.1):1, for example, 0.0005:1, 0.001:1, 0.005:1, 0.01:1, 0.05:1, 0.1:1 or any combination thereof.

[0068] In addition, the thickness of the aluminum-silicon alloy substrate can be 0.5 to 10 mm, for example, 0.5 mm, 1 mm, 3 mm, 5 mm, 7 mm, 10 mm or any combination thereof.

[0069] Generally, there is a relatively clear boundary between the composite layer and the aluminum alloy substrate. In practice, the aluminum-silicon alloy material can be cut along its thickness direction (the resulting cut surface is basically parallel to the thickness direction of the aluminum-silicon alloy material (which is also the thickness direction of the composite layer or the aluminum-silicon alloy substrate). Then, the cut surface is detected by scanning electron microscopy (SEM) or optical microscopy, and the thickness and other characteristics of the film layers such as the composite layer and the aluminum-silicon alloy substrate are measured.

[0070] In addition, the composite layer may contain oily organic matter, which helps to further reduce the surface roughness of aluminum-silicon alloy materials and improve their wear resistance and corrosion resistance.

[0071] Specifically, the aforementioned composite layer typically has a porous structure (generally nanoscale pores, i.e., pore size is nanometers). These porous structures have features such as pore defects, which allow oily organic matter to be adsorbed into the composite layer through physical adsorption, capillary action, etc. Based on the lubricating effect of the oily organic matter, the surface roughness of the composite layer can be reduced. At the same time, the oily organic matter adsorbed into the composite layer is equivalent to forming a protective film on one side, which can improve the wear resistance and corrosion resistance of the composite layer, thereby reducing the surface roughness of the aluminum-silicon alloy material and improving its wear resistance and corrosion resistance.

[0072] Specifically, the oil-based organic material may include perfluoropolyethers with a molecular weight of 1000 to 4000. The molecular weight of the perfluoropolyether is, for example, a range of 1000, 1500, 2000, 2500, 3000, 3500, 4000 or any two of these. The perfluoropolyether has a low viscosity, which facilitates its penetration into the composite layer and reduces the surface roughness of the composite layer. At the same time, the use of the perfluoropolyether is beneficial to further improve the wear resistance and corrosion resistance of the composite layer.

[0073] In this embodiment of the invention, the aluminum-silicon alloy substrate can be a conventional aluminum-silicon alloy material in the art, such as an aluminum-silicon alloy component used in electronic devices. The aluminum-silicon alloy component can be a sandblasted component or an aluminum-silicon alloy die-cast component prepared by a die-casting process, etc., and there are no particular limitations on this.

[0074] This invention also provides a method for preparing the above-mentioned aluminum-silicon alloy material, comprising the following steps: subjecting an aluminum-silicon alloy substrate to nickel immersion activation treatment, thereby forming a nickel particle layer on the surface of the aluminum-silicon alloy substrate to obtain a first intermediate; subjecting the first intermediate to electroless nickel-phosphorus plating treatment, thereby forming a nickel-phosphorus layer on the surface of the first intermediate to obtain a second intermediate; polishing the surface of the nickel-phosphorus layer of the second intermediate to obtain a third intermediate; subjecting the third intermediate to heat treatment to obtain a fourth intermediate; and subjecting the fourth intermediate to oil immersion treatment to obtain the aluminum-silicon alloy material.

[0075] The method for preparing aluminum-silicon alloy materials provided in this invention is also a surface treatment method for aluminum-silicon alloy materials (or a method for surface treatment of aluminum-silicon alloys with corrosion resistance, wear resistance and low roughness). By sequentially performing nickel immersion activation treatment, chemical nickel-phosphorus plating treatment, polishing, heat treatment and oil immersion treatment on the aluminum-silicon alloy substrate, it is possible to effectively achieve corrosion resistance, wear resistance and low roughness surface treatment of aluminum-silicon alloy materials (such as aluminum-silicon alloy parts), significantly reduce the surface roughness of aluminum-silicon alloy materials, and at the same time improve the corrosion resistance and wear resistance of aluminum-silicon alloy materials.

[0076] In this embodiment of the invention, an alkaline nickel immersion activation solution can be used for nickel immersion activation treatment. That is, the aluminum-silicon alloy substrate is immersed in the alkaline nickel immersion activation solution for nickel immersion activation treatment. This is beneficial for removing the oxide layer on the surface of the aluminum-silicon alloy substrate in situ during activation, further improving the bonding strength and other properties of the composite layer formed by the nickel particle layer and the nickel-phosphorus layer with the aluminum alloy substrate, and improving the activation efficiency.

[0077] Specifically, the pH value of the alkaline nickel immersion activation solution can be greater than or equal to 12 (i.e., pH value ≥ 12), for example, greater than or equal to 12.2, or greater than or equal to 12.4, or greater than or equal to 12.5, or greater than or equal to 12.8, or greater than or equal to 13, or greater than or equal to 13.2, or greater than or equal to 13.5, etc.

[0078] Specifically, the alkaline nickel immersion activation solution can be an aqueous solution containing a nickel source and a pH adjuster. That is, the solvent of the alkaline nickel immersion activation solution is water, the nickel source can include nickel salts, such as nickel chloride and / or nickel sulfate, etc., and the pH adjuster can include inorganic alkali (specifically, an aqueous solution of inorganic alkali) and / or ammonia. The inorganic alkali can include hydroxides of alkali metals, such as sodium hydroxide.

[0079] In this embodiment of the invention, the alkaline nickel immersion activation solution contains a pH adjuster, which can remove the oxide layer on the surface of the aluminum-silicon alloy substrate in situ during nickel immersion activation, further improve the bonding strength and other properties of the composite layer formed by the nickel particle layer and the nickel-phosphorus layer with the aluminum alloy substrate, and improve the activation efficiency.

[0080] Specifically, in the alkaline nickel immersion activation solution, the concentration of the nickel source can be 40–80 g / L, for example, 40 g / L, 45 g / L, 50 g / L, 55 g / L, 60 g / L, 65 g / L, 70 g / L, 75 g / L, 80 g / L, or any combination thereof.

[0081] In addition, alkaline nickel immersion activation solutions may also include pH buffers, which help stabilize the pH value during the nickel immersion activation process.

[0082] Specifically, in the alkaline nickel immersion activation solution, the concentration of the pH buffer can be 50–100 g / L, for example, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, or any combination thereof.

[0083] In some embodiments, the pH buffer may include diammonium hydrogen phosphate and / or ammonium chloride.

[0084] In addition, the alkaline nickel immersion activation solution may include a corrosion inhibitor. Since the alkaline nickel immersion activation solution is alkaline, it is easy to cause over-corrosion of the aluminum-silicon alloy substrate during the nickel immersion activation process. By introducing a corrosion inhibitor, the aluminum-silicon alloy substrate can be prevented from being over-corroded, thereby further ensuring the performance of the aluminum-silicon alloy material.

[0085] Specifically, in the alkaline nickel immersion activation solution, the concentration of the corrosion inhibitor can be 10 to 20 g / L, for example, 10 g / L, 12 g / L, 14 g / L, 15 g / L, 17 g / L, 19 g / L, 20 g / L or any combination thereof.

[0086] Specifically, corrosion inhibitors may include organic alcohol corrosion inhibitors, specifically polyethylene glycol.

[0087] In some specific embodiments, the pH adjuster includes a first pH adjuster and a second pH adjuster. The preparation process of the alkaline nickel immersion activation solution may include: mixing a nickel source, an aqueous solution of the first pH adjuster, a pH buffer, and a corrosion inhibitor to obtain a mixed solution; adjusting the mixed solution to pH ≥ 12 using an aqueous solution of the second pH adjuster to obtain the alkaline nickel immersion activation solution; wherein, the aqueous solution of the first pH adjuster may include ammonia, etc., and the concentration of the aqueous solution of the first pH adjuster in the alkaline nickel immersion activation solution may be 200-600 mL / L (i.e., the ratio of the volume of the aqueous solution of the first pH adjuster to the volume of the prepared alkaline nickel immersion activation solution is basically satisfied (200-600 mL): 1 L); the aqueous solution of the second pH adjuster may include an aqueous solution of an alkali metal hydroxide, such as sodium hydroxide solution.

[0088] In addition, the conditions for nickel immersion activation treatment can be: temperature of 30-50°C and time of 40-300 seconds (s), that is, the aluminum-silicon alloy substrate can be immersed in nickel immersion activation solution (such as the above-mentioned alkaline nickel immersion activation solution) at 30-50°C for 40-300 seconds to form a nickel particle layer on the surface of the aluminum-silicon alloy substrate.

[0089] For example, the temperature of the nickel immersion activation treatment can be a range of 30°C, 33°C, 35°C, 38°C, 40°C, 43°C, 45°C, 48°C, 50°C or any two of these, and the time can be a range of 40s, 50s, 70s, 90s, 100s, 130s, 150s, 180s, 200s, 230s, 250s, 280s, 300s or any two of these.

[0090] In practice, the aluminum-silicon alloy substrate can be ultrasonically cleaned in pure water and then placed in a nickel immersion activation solution for nickel immersion activation treatment.

[0091] Compared to conventional activation methods (pretreatment methods) such as secondary zinc immersion activation treatment, the embodiments of the present invention can simplify the pretreatment steps of aluminum-silicon alloy substrates and improve the bonding force between the nickel-phosphorus layer formed by subsequent electroless nickel-phosphorus plating and the aluminum-silicon alloy substrate, prevent the nickel-phosphorus layer from peeling off during subsequent polishing, thereby improving polishing efficiency, reducing the surface roughness of the obtained aluminum-silicon alloy material, and improving the bonding force between the composite layer formed by the nickel particle layer and the nickel-phosphorus layer in the obtained aluminum-silicon alloy material and the aluminum-silicon alloy substrate.

[0092] Furthermore, the electroless nickel-phosphorus plating process can include: sequentially treating the first intermediate with an alkaline electroless nickel-phosphorus plating solution and an acidic electroless nickel-phosphorus plating solution, that is, first treating the first intermediate with an alkaline electroless nickel-phosphorus plating solution (i.e., immersing the first intermediate in the alkaline electroless nickel-phosphorus plating solution for electroless nickel-phosphorus plating), and then treating it with an acidic electroless nickel-phosphorus plating solution (i.e., immersing the first intermediate after the alkaline electroless nickel-phosphorus plating solution in the acidic electroless nickel-phosphorus plating solution for electroless nickel-phosphorus plating). This approach helps to improve both the wear resistance and corrosion resistance of the formed nickel-phosphorus layer, while also increasing the deposition efficiency of the nickel-phosphorus layer.

[0093] Specifically, the pH value of the alkaline electroless nickel-phosphorus plating solution can be 10 to 11.

[0094] Specifically, the conditions for electroless nickel-phosphorus plating using alkaline electroless nickel-phosphorus solution can be: temperature of 60-80℃ and deposition time of 0.5-1h.

[0095] In addition, the pH value of acidic nickel-phosphorus plating solution is 4.5-5.0;

[0096] In addition, the conditions for electroless nickel-phosphorus plating using acidic electroless nickel-phosphorus plating solution can be: temperature 80-90℃, deposition time 0.5-2h.

[0097] In specific implementation, after the nickel immersion activation treatment is completed, the first intermediate obtained by washing with pure water can be used (for example, the first intermediate can be washed by soaking in pure water). Then, it can be immersed in an alkaline electroless nickel-phosphorus plating solution with a certain pH value (e.g., 10-11) and temperature (e.g., 60-80℃) to deposit a nickel-phosphorus plating layer (first sub-region). Then, it can be immersed in an acidic electroless nickel-phosphorus plating solution with a certain pH value (e.g., 4.5-5.0) and temperature (e.g., 80-90℃) to deposit a nickel-phosphorus plating layer (second sub-region), thereby forming a nickel-phosphorus layer on the surface of the first intermediate.

[0098] In this embodiment of the invention, conventional alkaline electroless nickel-phosphorus plating solutions and acidic electroless nickel-phosphorus plating solutions in the art can be used, which are commercially available (the alkaline electroless nickel-phosphorus plating solution used can be a commercial alkaline electroless nickel-phosphorus plating solution, and the acidic electroless nickel-phosphorus plating solution used can be a commercial acidic electroless nickel-phosphorus plating solution), and there are no particular limitations in this regard.

[0099] In addition, polishing wheels can be used during the polishing process. The polishing wheels can be cotton polishing wheels or wool polishing wheels, which can help improve polishing efficiency and reduce the surface roughness of the nickel-phosphorus layer.

[0100] Specifically, during the polishing process, a high-speed polishing wheel can be used to polish the surface of the nickel-phosphorus layer. The speed of the polishing wheel can be greater than 8000 rpm, and the polishing time can be 0.5 to 2 minutes.

[0101] In addition, during polishing, polishing paste is present on the surface of the polishing wheel. Specifically, a fine polishing paste (the abrasive size (particle size) in the polishing paste is less than 50 nm) can be used. The abrasives in the polishing paste include, for example, diamond and / or silicon nitride.

[0102] In this embodiment of the invention, the polishing compound (such as a fine polishing compound) used can be a conventional polishing compound in the art, which is commercially available and is not particularly limited thereto.

[0103] In the above preparation process, heat treatment of the third intermediate can promote the formation of nickel-phosphorus compounds from nickel and phosphorus elements in the nickel-phosphorus layer, and facilitate diffusion (interpenetration) between the composite layer formed by the nickel particle layer and the nickel-phosphorus layer and the aluminum alloy substrate, thereby improving the bonding force between the composite layer and the aluminum-silicon alloy substrate.

[0104] Specifically, the heat treatment can be carried out in an atmospheric environment (i.e., in air), and the temperature can be 200–350°C for 2–3 hours.

[0105] In practice, the third intermediate can be rinsed and cleaned to remove impurities such as polishing paste remaining on its surface, and then placed under heat treatment conditions for heat treatment.

[0106] In addition, during the above preparation process, an oil immersion treatment can be performed. That is, the fourth intermediate is immersed in an oil immersion treatment. After the oil immersion treatment is completed, it is taken out of the oil immersion treatment, drained and washed, and then dried (for example, placed in a drying oven or other drying equipment at 75-85°C (e.g., 80°C)) to obtain the aluminum-silicon alloy material.

[0107] Specifically, the oil immersion solution includes oily organics, as mentioned above, including perfluoropolyethers with a molecular weight of 1000 to 4000.

[0108] Specifically, the oil immersion treatment can be carried out at a temperature of 20–40°C for 24–48 hours.

[0109] In this embodiment of the invention, the above-described preparation process can produce an aluminum-silicon alloy material with low surface roughness, good corrosion resistance, and good wear resistance. Specifically, it can achieve a surface roughness of less than 0.7 μm, while also exhibiting a uniform surface color without peeling, bubbles, or other defects. Furthermore, the preparation method of this invention has advantages such as a short process flow and low cost, making it suitable for practical industrial applications.

[0110] This invention also provides a structural component comprising the aforementioned aluminum-silicon alloy material or an aluminum-silicon alloy material prepared according to the aforementioned method for preparing the aluminum-silicon alloy material. This structural component has advantages corresponding to the aforementioned aluminum-silicon alloy material, which will not be elaborated further.

[0111] In this embodiment of the invention, the above-mentioned structural component can be a conventional structural component formed of aluminum-silicon alloy in the art. For example, the structural component is a structural component with heat dissipation function, which can be a heat sink or other component applied to electronic devices, but is not limited thereto.

[0112] This invention also provides an electronic device including the above-described structural components. This electronic device has advantages corresponding to the above-described aluminum-silicon alloy material, which will not be elaborated further.

[0113] In this embodiment of the invention, the electronic device may be a conventional device in the art that includes structural components formed of aluminum-silicon alloy, such as an electronic device or electronic product, but is not limited thereto.

[0114] The present invention will be further described below through specific embodiments.

[0115] Example 1

[0116] In this embodiment 1, the aluminum-silicon alloy substrate is an aluminum-silicon alloy die-cast part. The aluminum-silicon alloy die-cast part undergoes a corrosion-resistant, wear-resistant, and low-roughness surface treatment to obtain the aluminum-silicon alloy material. The specific surface treatment process (the preparation process of the aluminum-silicon alloy material) is as follows:

[0117] (1) Nickel immersion activation treatment: After ultrasonic cleaning of the aluminum-silicon alloy substrate in pure water, it is directly immersed in an alkaline nickel immersion activation solution with a pH of 12.5 and soaked at 45°C for 60 seconds to form a nickel particle layer on the surface of the aluminum-silicon alloy substrate, thus obtaining the first intermediate.

[0118] The alkaline nickel immersion activation solution is prepared as follows: 45g of nickel sulfate, ammonia, diammonium hydrogen phosphate, polyethylene glycol, and water are mixed to obtain a mixture; the pH of the mixture is adjusted to 12.5 using sodium hydroxide solution to obtain an alkaline nickel immersion activation solution (approximately 1L); wherein, in the alkaline nickel immersion activation solution, the concentration of ammonia is 580mL / L (i.e., the volume ratio of ammonia to the volume of the prepared alkaline nickel immersion activation solution is 580mL:1L), the concentration of diammonium hydrogen phosphate is 58g / L, and the concentration of polyethylene glycol is 15g / L;

[0119] (2) Electroless nickel-phosphorus plating treatment: After the first intermediate (aluminum-silicon alloy substrate after surface nickel immersion activation) is cleaned by soaking in pure water, it is first immersed in an alkaline electroless nickel-phosphorus plating solution at a temperature of 60°C and a pH value of 10 to deposit a nickel-phosphorus plating layer for 1 hour (forming the first sub-region); then it is immersed in an acidic electroless nickel-phosphorus plating solution at a temperature of 80°C and a pH value of 4.6 to deposit a nickel-phosphorus plating layer for 1 hour (forming the second sub-region), so as to form a nickel-phosphorus layer on the surface of the first intermediate and obtain the second intermediate;

[0120] (3) Polishing: Using a wool polishing wheel and applying a fine polishing compound to the polishing wheel, the polishing wheel rotates at 10,000 rpm and the nickel-phosphorus layer surface of the second intermediate is polished for 1 minute to obtain the third intermediate;

[0121] (4) Heat treatment: The third intermediate is rinsed and cleaned (i.e., the polished nickel-phosphorus layer is rinsed and cleaned) to remove the polishing paste and other impurities remaining on the surface of the nickel-phosphorus layer of the third intermediate. Then, under atmospheric conditions, the temperature is raised to 300°C in the furnace and held for 3 hours. Then, the temperature is cooled to room temperature in the furnace to obtain the fourth intermediate.

[0122] (5) Oil immersion treatment: The fourth intermediate is immersed in perfluoropolyether at a temperature of 20°C and a molecular weight of 1000 for 24 hours, then taken out, drained and washed, and then dried in an 80°C drying oven to obtain aluminum-silicon alloy material.

[0123] In the above process, after the nickel immersion activation treatment in step (1), a nickel particle layer is formed on the surface of the aluminum-silicon alloy substrate. The microscopic image of the nickel particle layer obtained by scanning electron microscopy (SEM) analysis is shown below. Figure 1 ,from Figure 1 As can be seen, a layer of uniformly dispersed first nickel particles is deposited on the surface of the aluminum-silicon alloy substrate. These first nickel particles form a nickel particle layer, and there are gaps in the nickel particle layer that expose the surface of the aluminum-silicon alloy substrate. The particle size of the first nickel particles is approximately 160 nm.

[0124] Following the electroless nickel-phosphorus plating treatment in step (2), a nickel-phosphorus layer is formed on the surface of the first intermediate. This nickel-phosphorus layer covers the nickel particle layer, forming a composite layer deposited on the surface of the aluminum-silicon alloy. The microscopic image (SEM image) of the nickel-phosphorus layer is shown below. Figure 2 ,from Figure 2 As can be seen, the nickel-phosphorus layer is complete and dense, covering the entire surface of the first intermediate (the nickel-phosphorus layer includes a filling portion that fills the gaps in the nickel particle layer and a covering portion that covers the nickel particle layer); the nickel-phosphorus layer contains second nickel particles, which are micron-sized (the particle size of the second nickel particles is larger than the particle size of the first nickel particles in the nickel particle layer).

[0125] In addition, based on the XRD analysis of the composite layer, the XRD pattern of the composite layer is shown in [see image]. Figure 4 ,from Figure 4 As can be seen, the composite layer contains elemental nickel and nickel-phosphorus compounds (Ni3P), with the nickel element in the composite layer mainly existing as elemental nickel (second nickel particles).

[0126] In addition, based on the EDS analysis of the composite layer, the EDS spectrum of the composite layer is shown below. Figure 5 The mass percentage of phosphorus in the composite layer was measured to be approximately 9.8%; among them, in the nickel-phosphorus layer, the phosphorus content in the first sub-region was less than that in the second sub-region.

[0127] Furthermore, by cutting the prepared aluminum-silicon alloy material along its thickness direction and detecting the resulting cut surface (which is basically parallel to the thickness direction of the aluminum-silicon alloy material) using SEM, the thickness of the composite layer was measured to be approximately 18.5 μm; the ratio of the thickness of the composite layer to the thickness of the aluminum-silicon alloy substrate was approximately 0.0185.

[0128] In addition, the adhesion between the composite layer and the aluminum-silicon alloy substrate was tested using a cross-cut adhesion test. The test results are shown in the figure below. Figure 3 (During testing, scratches were made on the composite layer, dividing its surface into multiple grids; 3M tape was then applied to the surface of the composite layer, and the tape was peeled off to observe the grid detachment.) Figure 3 (Optical micrograph of 3M tape peeled off the surface of the composite layer) Figure 3As can be seen, the composite layer on the surface of the aluminum-silicon alloy substrate did not peel off (indicating that the bonding force between the composite layer and the aluminum-silicon alloy substrate is basically 100%), demonstrating good bonding strength.

[0129] In addition, the surface roughness of the aluminum-silicon alloy material was measured using a roughness meter, and the surface roughness of the aluminum-silicon alloy material was found to be approximately 40 nm.

[0130] In addition, a neutral salt spray test was conducted on the aluminum-silicon alloy material, and the time T at which it began to corrode was measured to be approximately 140 hours (corrosion phenomena within 140 hours).

[0131] In addition, the surface microhardness of the aluminum-silicon alloy material was tested using a Vickers hardness tester, and the measured microhardness (micro Vickers hardness) of the aluminum-silicon alloy material reached HV550.

[0132] Example 2

[0133] In this embodiment 2, the aluminum-silicon alloy substrate is an aluminum-silicon alloy sandblasted part. The aluminum-silicon alloy sandblasted part undergoes a corrosion-resistant, wear-resistant, and low-roughness surface treatment to obtain the aluminum-silicon alloy material. The specific surface treatment process (the preparation process of the aluminum-silicon alloy material) is as follows:

[0134] (1) Nickel immersion activation treatment: After ultrasonic cleaning of the aluminum-silicon alloy sandblasting parts in pure water, they are directly immersed in an alkaline nickel immersion activation solution with a pH of 13.2 and soaked at 40°C for 180 seconds to form a nickel particle layer on the surface of the aluminum-silicon alloy substrate, thus obtaining the first intermediate.

[0135] The alkaline nickel immersion activation solution is prepared as follows: 45g of nickel chloride, ammonia, ammonium chloride, polyethylene glycol, and water are mixed to obtain a mixture; the pH of the mixture is adjusted to 13.2 using sodium hydroxide solution to obtain an alkaline nickel immersion activation solution (approximately 1L); wherein, in the alkaline nickel immersion activation solution, the concentration of ammonia is 400mL / L (i.e., the volume ratio of ammonia to the volume of the prepared alkaline nickel immersion activation solution is 400mL:1L), the concentration of ammonium chloride is 80g / L, and the concentration of polyethylene glycol is 10g / L;

[0136] (2) Electroless nickel-phosphorus plating treatment: After the first intermediate is soaked and cleaned with pure water, it is first immersed in an alkaline electroless nickel-phosphorus plating solution with a temperature of 70℃ and a pH of 10.5 to deposit a nickel-phosphorus plating layer for 0.5h, and then immersed in an acidic electroless nickel-phosphorus plating solution with a temperature of 85℃ and a pH of 4.7 to deposit a nickel-phosphorus plating layer for 1.5h, so as to form a nickel-phosphorus layer on the surface of the first intermediate and obtain the second intermediate.

[0137] (3) Polishing: Using a cotton polishing wheel and applying fine polishing paste to the polishing wheel, the polishing wheel speed is 9000 rpm, and the nickel-phosphorus layer surface of the second intermediate is polished for 1.5 min to obtain the third intermediate;

[0138] (4) Heat treatment: The third intermediate is flushed and cleaned to remove impurities such as polishing paste remaining on the surface of the nickel-phosphorus layer of the third intermediate. Then, under atmospheric conditions, it is heated to 320°C in the furnace and held for 2.5 hours. Then, it is cooled to room temperature in the furnace to obtain the fourth intermediate.

[0139] (5) Oil immersion treatment: The fourth intermediate is immersed in perfluoropolyether at 30°C and with a molecular weight of 1500 for 36 hours, then taken out, drained and washed, and then dried in an 80°C drying oven to obtain aluminum-silicon alloy material.

[0140] Example 3

[0141] In this embodiment 3, the aluminum-silicon alloy substrate is an aluminum-silicon alloy die-cast part. The aluminum-silicon alloy die-cast part is subjected to corrosion-resistant, wear-resistant, and low-roughness surface treatment to obtain the aluminum-silicon alloy material.

[0142] The difference between Example 3 and Example 1 is that the nickel immersion activation process is different, while other steps and conditions are the same as in Example 1. The specific nickel immersion activation process in Example 3 is as follows: After ultrasonic cleaning of the aluminum-silicon alloy die-casting parts in pure water, they are directly immersed in an alkaline nickel immersion activation solution with a pH of 12.2 and soaked at 30°C for 45 seconds to form a nickel particle layer on the surface of the aluminum-silicon alloy substrate, thus obtaining the first intermediate. The alkaline nickel immersion activation solution is prepared as follows: 50g of nickel chloride, ammonia, ammonium chloride, polyethylene glycol, and water are mixed to obtain a mixed solution. The pH of the mixed solution is adjusted to 12.2 using sodium hydroxide solution to obtain an alkaline nickel immersion activation solution (approximately 1L). The concentration of ammonia in the alkaline nickel immersion activation solution is 200mL / L (i.e., the volume ratio of ammonia to the volume of the prepared alkaline nickel immersion activation solution is 200mL:1L), the concentration of ammonium chloride is 60g / L, and the concentration of polyethylene glycol is 19g / L.

[0143] Example 4

[0144] In this embodiment 4, the aluminum-silicon alloy substrate is an aluminum-silicon alloy die-cast part. The aluminum-silicon alloy die-cast part is subjected to corrosion-resistant, wear-resistant, and low-roughness surface treatment to obtain the aluminum-silicon alloy material.

[0145] The difference between Example 4 and Example 1 is that the nickel immersion activation process is different, while other steps and conditions are the same as in Example 1. The specific nickel immersion activation process in Example 4 is as follows: After ultrasonic cleaning of the aluminum-silicon alloy die-casting parts in pure water, they are directly immersed in an alkaline nickel immersion activation solution with a pH of 12.4 and soaked at 32°C for 130 seconds to form a nickel particle layer on the surface of the aluminum-silicon alloy substrate, thus obtaining the first intermediate. The alkaline nickel immersion activation solution is prepared as follows: 62g of nickel sulfate, ammonia, ammonium chloride, polyethylene glycol, and water are mixed to obtain a mixed solution. The pH of the mixed solution is adjusted to 12.4 using sodium hydroxide solution to obtain an alkaline nickel immersion activation solution (approximately 1L). The concentration of ammonia in the alkaline nickel immersion activation solution is 350mL / L (i.e., the volume ratio of ammonia to the volume of the prepared alkaline nickel immersion activation solution is 350mL:1L), the concentration of diammonium hydrogen phosphate is 68g / L, and the concentration of polyethylene glycol is 17g / L.

[0146] Example 5

[0147] In this embodiment 5, the aluminum-silicon alloy substrate is an aluminum-silicon alloy die-cast part. The aluminum-silicon alloy die-cast part is subjected to corrosion-resistant, wear-resistant, and low-roughness surface treatment to obtain the aluminum-silicon alloy material.

[0148] The difference between Example 5 and Example 1 lies in the nickel immersion activation process; the other steps and conditions are the same as in Example 1. The specific details of the nickel immersion activation process in Example 5 are as follows: After ultrasonic cleaning of the aluminum-silicon alloy die-casting part in pure water, it is directly immersed in an alkaline nickel immersion activation solution with a pH of 12.8 and soaked at 36°C for 215 seconds to form a nickel particle layer on the surface of the aluminum-silicon alloy substrate, thus obtaining the first intermediate. The alkaline nickel immersion activation solution is prepared according to the following process: 75% nickel chloride... g, ammonia, ammonium chloride, diammonium hydrogen phosphate, polyethylene glycol, and water are mixed to obtain a mixture; the pH of the mixture is adjusted to 12.8 using sodium hydroxide solution to obtain an alkaline nickel immersion activation solution (approximately 1 L); wherein, in the alkaline nickel immersion activation solution, the concentration of ammonia is 500 mL / L (i.e., the volume ratio of ammonia to the volume of the prepared alkaline nickel immersion activation solution is 500 mL: 1 L), the concentration of ammonium chloride is 36 g / L, the concentration of diammonium hydrogen phosphate is 39 g / L, and the concentration of polyethylene glycol is 14 g / L.

[0149] Example 6

[0150] In this embodiment 6, the aluminum-silicon alloy substrate is an aluminum-silicon alloy die-cast part. The aluminum-silicon alloy die-cast part is subjected to corrosion-resistant, wear-resistant, and low-roughness surface treatment to obtain the aluminum-silicon alloy material.

[0151] The difference between Example 6 and Example 1 is that the nickel immersion activation process is different, while other steps and conditions are the same as in Example 1. The specific nickel immersion activation process in Example 6 is as follows: After ultrasonic cleaning of the aluminum-silicon alloy die-casting part in pure water, it is directly immersed in an alkaline nickel immersion activation solution with a pH of 13.5 and immersed at 48°C for 280 seconds to form a nickel particle layer on the surface of the aluminum-silicon alloy substrate, thus obtaining the first intermediate. The alkaline nickel immersion activation solution is prepared as follows: 50g of nickel chloride, 35g of nickel sulfate, ammonia, ammonium chloride, polyethylene glycol, and water are mixed to obtain a mixed solution. The pH of the mixed solution is adjusted to 13.5 using sodium hydroxide solution to obtain an alkaline nickel immersion activation solution (approximately 1L). The concentration of ammonia in the alkaline nickel immersion activation solution is 280mL / L (i.e., the volume ratio of ammonia to the volume of the prepared alkaline nickel immersion activation solution is 280mL:1L), the concentration of ammonium chloride is 95g / L, and the concentration of polyethylene glycol is 12g / L.

[0152] Example 7

[0153] In this embodiment 7, the aluminum-silicon alloy substrate is an aluminum-silicon alloy die-cast part. The aluminum-silicon alloy die-cast part is subjected to corrosion-resistant, wear-resistant, and low-roughness surface treatment to obtain the aluminum-silicon alloy material.

[0154] The difference between Example 7 and Example 1 is that in the electroless nickel-phosphorus plating process, only an alkaline electroless nickel-phosphorus plating solution is used for electroless nickel-phosphorus plating, while the other steps and conditions are the same as in Example 1. The specific electroless nickel-phosphorus plating process in Example 7 is as follows: After the first intermediate is rinsed with pure water, it is immersed in an alkaline electroless nickel-phosphorus plating solution with a temperature of 75°C and a pH of 10.2 to deposit a nickel-phosphorus plating layer for 1 hour, so as to form a nickel-phosphorus layer on the surface of the first intermediate and obtain the second intermediate.

[0155] Example 8

[0156] In this embodiment 8, the aluminum-silicon alloy substrate is an aluminum-silicon alloy die-cast part. The aluminum-silicon alloy die-cast part is subjected to corrosion-resistant, wear-resistant, and low-roughness surface treatment to obtain the aluminum-silicon alloy material.

[0157] The difference between Example 8 and Example 1 is that in the electroless nickel-phosphorus plating process, only an acidic electroless nickel-phosphorus plating solution is used for electroless nickel-phosphorus plating, while the other steps and conditions are the same as in Example 1. The specific electroless nickel-phosphorus plating process in Example 8 is as follows: After the first intermediate is rinsed with pure water, it is immersed in an acidic electroless nickel-phosphorus plating solution with a temperature of 88°C and a pH of 4.9 to deposit a nickel-phosphorus plating layer for 2 hours, so as to form a nickel-phosphorus layer on the surface of the first intermediate and obtain the second intermediate.

[0158] By performing scanning electron microscopy (SEM), XRD, and EDS analyses on the aluminum-silicon alloy materials and their respective film layers in each embodiment (the relevant tests are referred to in Example 1), the film layer structure and composition characteristics of the aluminum-silicon alloy materials in each embodiment were determined as follows: (1) The nickel particle layer includes multiple first nickel particles and gaps between them and the surface of the aluminum-silicon alloy substrate. These first nickel particles are basically uniformly distributed on the surface of the aluminum-silicon alloy material. The first nickel particles are nanoscale (the specific particle size of the first nickel particles in each embodiment and comparative example is shown in Table 1); (2) The nickel-phosphorus layer covers the nickel particle layer and forms a composite layer covering the surface of the aluminum-silicon alloy substrate with the nickel particle layer; nickel-phosphorus The layer is complete and dense, including a filling part that fills the gaps in the nickel particle layer and a covering part that covers the nickel particle layer; the nickel-phosphorus layer contains elemental nickel and nickel-phosphorus compounds, and the nickel element in the nickel-phosphorus layer is mainly present as elemental nickel (second nickel particles), and the second nickel particles are micron-sized (the particle size of the second nickel particles is larger than the particle size of the first nickel particles in the nickel particle layer); (3) the phosphorus content in the composite layer is about 6% to 30%, and the rest is basically nickel; in the nickel-phosphorus layers of Examples 1 to 6, the phosphorus content in the first sub-region is less than the phosphorus content in the second sub-region; (4) the thickness of the composite layer is shown in Table 1; the ratio of the thickness of the composite layer to the thickness of the aluminum-silicon alloy substrate is shown in Table 1.

[0159] In addition, according to ASTM D3359, the bonding force between the composite layer and the aluminum-silicon alloy substrate in each embodiment and comparative example was measured by cross-cut adhesion test. The surface roughness of the aluminum-silicon alloy material (also the surface roughness of the nickel-phosphorus layer) was measured by a roughness tester. According to ASTM B117, the time T for the aluminum-silicon alloy material to begin corrosion was measured by a neutral salt spray test. The micro Vickers hardness of the aluminum-silicon alloy material was measured by a Vickers hardness tester. The results are summarized in Table 1.

[0160] Table 1

[0161]

[0162] As can be seen from Table 1, Examples 1 to 7 can reduce the surface roughness of the prepared aluminum-silicon alloy material, specifically to below 40 nm, and can improve the bonding force between the composite layer and the aluminum-silicon alloy substrate, specifically to achieve a bonding force of over 98%. At the same time, it can improve the corrosion resistance of the aluminum-silicon alloy material, with the time T for the material to begin corrosion in the neutral salt spray test not less than 120 h.

[0163] In contrast to Example 6, in Examples 1-5, the particle size of the first nickel particle in the nickel particle layer is controlled to be no more than 200 nm, which can further improve the bonding strength and other properties of the composite layer and the aluminum-silicon alloy substrate.

[0164] In contrast to Examples 7 and 8, Examples 1 to 5 use alkaline electroless nickel-phosphorus plating solution and acidic electroless nickel-phosphorus plating solution to electrolessly plating the first intermediate, which can further improve the corrosion resistance (the time T for the start of corrosion in the neutral salt spray test is not less than 132h) and hardness (not less than HV550) of the aluminum-silicon alloy material.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An aluminum-silicon alloy material, characterized in that, The material includes an aluminum-silicon alloy substrate and a composite layer on the surface of the aluminum-silicon alloy substrate. The composite layer includes a nickel-phosphorus layer and a nickel particle layer between the nickel-phosphorus layer and the aluminum-silicon alloy substrate. The surface roughness of the aluminum-silicon alloy material is less than or equal to 0.7 μm.

2. The aluminum-silicon alloy material according to claim 1, characterized in that, The surface roughness of the aluminum-silicon alloy material is less than or equal to 50 nm.

3. The aluminum-silicon alloy material according to claim 1, characterized in that, The micro Vickers hardness of the aluminum-silicon alloy material is above HV500.

4. The aluminum-silicon alloy material according to claim 1, characterized in that, The bonding strength between the composite layer and the aluminum-silicon alloy substrate is greater than or equal to 98%.

5. The aluminum-silicon alloy material according to claim 1, characterized in that, The corrosion resistance of the aluminum-silicon alloy material satisfies the following condition: when the aluminum-silicon alloy material is subjected to a neutral salt spray test, the time for corrosion to begin is greater than or equal to 120 hours.

6. The aluminum-silicon alloy material according to claim 1, characterized in that, The nickel particle layer includes first nickel particles, and the nickel-phosphorus layer includes second nickel particles, wherein the particle size of the second nickel particles is larger than that of the first nickel particles. And / or, the nickel-phosphorus layer includes second nickel particles with a particle size on the micrometer scale; And / or, the nickel particle layer includes first nickel particles with a particle size of 1 to 200 nm.

7. The aluminum-silicon alloy material according to any one of claims 1-6, characterized in that, The composite layer comprises nickel particles and nickel-phosphorus compounds; And / or, the mass percentage of phosphorus in the composite layer is 6% to 30%; And / or, the composite layer includes a first region and a second region located on the side of the first region opposite to the aluminum-silicon alloy substrate, wherein the phosphorus content of the first region is less than the phosphorus content of the second region.

8. The aluminum-silicon alloy material according to any one of claims 1-6, characterized in that, The nickel particle layer includes gaps that expose the surface of the aluminum-silicon alloy substrate, and the nickel-phosphorus layer includes a covering portion that covers the nickel particle layer and a filling portion that fills the gaps in the nickel particle layer.

9. The aluminum-silicon alloy material according to any one of claims 1-6, characterized in that, The thickness of the composite layer is 5–50 μm; And / or, the ratio of the thickness of the composite layer to the thickness of the aluminum-silicon alloy substrate is (0.0005~0.1):

1.

10. The aluminum-silicon alloy material according to any one of claims 1-6, characterized in that, The composite layer contains oil-based organic matter.

11. The aluminum-silicon alloy material according to claim 10, characterized in that, The oil-based organic compounds include perfluoropolyethers with a molecular weight of 1000 to 4000.

12. A method for preparing an aluminum-silicon alloy material according to any one of claims 1-11, characterized in that, Includes the following steps: An aluminum-silicon alloy substrate is subjected to a nickel immersion activation treatment, which forms a nickel particle layer on the surface of the aluminum-silicon alloy substrate to obtain a first intermediate. The first intermediate is subjected to electroless nickel-phosphorus plating treatment, and a nickel-phosphorus layer is formed on the surface of the first intermediate through the electroless nickel-phosphorus plating treatment to obtain the second intermediate; The surface of the nickel-phosphorus layer of the second intermediate is polished to obtain the third intermediate; The third intermediate is heat-treated to obtain the fourth intermediate; The fourth intermediate is subjected to oil immersion treatment to obtain the aluminum-silicon alloy material.

13. The preparation method according to claim 12, characterized in that, The nickel immersion activation treatment is performed using an alkaline nickel immersion activation solution, wherein... The pH value of the alkaline nickel immersion activation solution is ≥12; And / or, the alkaline nickel immersion activation solution includes a nickel source, the concentration of which is 40-80 g / L; And / or, the alkaline nickel immersion activation solution includes a pH buffer, the pH buffer including diammonium hydrogen phosphate and / or ammonium chloride; in the alkaline nickel immersion activation solution, the concentration of the pH buffer is 50-100 g / L; And / or, the alkaline nickel immersion activation solution includes a corrosion inhibitor, the corrosion inhibitor including polyethylene glycol; the concentration of the corrosion inhibitor in the alkaline nickel immersion activation solution is 10-20 g / L; And / or, the conditions for the nickel immersion activation treatment are: temperature of 30-50°C and time of 40-300s.

14. The preparation method according to claim 12 or 13, characterized in that, The electroless nickel-phosphorus plating process includes: sequentially electroless nickel-phosphorus plating with an alkaline electroless nickel-phosphorus plating solution and an acidic electroless nickel-phosphorus plating solution to treat the first intermediate with electroless nickel-phosphorus plating.

15. The preparation method according to claim 14, characterized in that, The pH value of the alkaline electroless nickel-phosphorus plating solution is 10-11; And / or, the conditions for electroless nickel-phosphorus plating using an alkaline electroless nickel-phosphorus plating solution are: temperature of 60-80℃ and deposition time of 0.5-1h; And / or, the pH value of the acidic nickel-phosphorus plating solution is 4.5-5.0; And / or, the conditions for electroless nickel-phosphorus plating using acidic electroless nickel-phosphorus plating solution are: temperature 80-90℃, deposition time 0.5-2h.

16. The preparation method according to claim 12, characterized in that, During the polishing process, a polishing wheel is used for polishing, wherein... The polishing wheel is a cotton polishing wheel or a wool polishing wheel; And / or, the polishing wheel rotates at a speed greater than 8000 rpm, and the polishing time is 0.5 to 2 min.

17. The preparation method according to claim 12, characterized in that, The heat treatment is carried out in an atmospheric environment, and the temperature of the heat treatment is 200-350℃, and the time is 2-3 hours.

18. The preparation method according to claim 12, characterized in that, The oil immersion treatment is carried out using an oil immersion solution comprising a perfluoropolyether with a molecular weight of 1000 to 4000. And / or, the oil immersion treatment is carried out at a temperature of 20–40°C for a time of 24–48 hours.

19. A structural component, characterized in that, Includes the aluminum-silicon alloy material according to any one of claims 1-11 or the aluminum-silicon alloy material prepared according to the preparation method according to any one of claims 12-18.

20. An electronic device, characterized in that, Includes the structural component as described in claim 19.

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