Process manufacturing method of aluminum substrate

Abstract

The invention discloses a technological manufacturing method of an aluminum substrate, which comprises the following steps: S1, carrying out ultrasonic cleaning for 15 minutes at the temperature of 60 DEG C by using a NaOH solution, soaking waste materials for 5 minutes by using a 10vol% nitric acid solution, then carrying out three-stage countercurrent rinsing, feeding the waste materials into a jaw crusher, and carrying out three-stage countercurrent rinsing on the waste materials; the graded fragments and synthetic metal powder are evenly mixed according to the proportion of 70%, 25% and 5%; through fragment multi-stage matching reinforcement and synthetic metal powder design, the waste utilization rate is greater than 95%, and the mechanical property is improved by 30%, so that the difficulty that a reinforced phase composite material cannot be recycled is overcome, the fragments are innovatively divided into three stages according to the particle size in the process, micropores are filled with superfine fragments, medium fragments form a matrix framework, and the strength of the reinforced phase composite material is improved. The coarse fragments provide reinforced support, and the three components are mixed according to the mass ratio of 75: 20: 5 to prepare the aluminum substrate, so that recycling of leftover materials is realized.

Description

Technical Field

[0001] This invention relates to the field of aluminum substrate processing technology, specifically to a process manufacturing method for aluminum substrates. Background Technology

[0002] Aluminum substrate is a metal-based copper-clad laminate with aluminum as the substrate. With the high thermal conductivity of aluminum, it can quickly conduct the heat of heat-generating components such as LEDs and power devices to the heat sink or housing, thereby significantly reducing the operating temperature. The heat dissipation efficiency is 5 to 10 times higher than that of traditional FR-4 substrate, extending the life of components. Aluminum substrate has outstanding advantages, especially in high-heat-density scenarios such as high-power lighting and automotive electronics.

[0003] In the field of aluminum substrate manufacturing, the current industry generally uses landfill disposal for scraps generated during the production of particle-reinforced aluminum matrix composites, such as 6061Al / SiCp, resulting in material waste. Because it contains 15-25 vol% silicon carbide reinforcing phase, traditional smelting will lead to component segregation and performance degradation. At the same time, the surface marking of existing aluminum substrates is mostly done by laser marking, which has problems such as easy peeling and poor temperature resistance, seriously affecting product traceability and service life. Summary of the Invention

[0004] The purpose of this invention is to provide a manufacturing method for an aluminum substrate to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for manufacturing an aluminum substrate, the method comprising the following steps:

[0006] Step S1: Use NaOH solution to perform ultrasonic cleaning at 60℃ for 15 minutes, then soak the waste in 10 vol% nitric acid solution for 5 minutes, and then perform three-stage countercurrent rinsing. Send the waste into a jaw crusher and mix the graded fragments with synthetic metal powder in a ratio of 70%, 25%, and 5%.

[0007] Step S2: The mixed material is isotropically pressurized using an oil-medium cold isostatic press to promote particle rearrangement and mechanical interlocking, forming a preform. Step-by-step pressure relief is used during pressure release.

[0008] Step S3: The billet is heated to 480±5℃ at a rate of 10℃ / min using a horizontal hydraulic extruder and held at that temperature for 2 hours. The extrusion cylinder temperature is set to 400~420℃ and the die holder temperature is set to 410~450℃, forming a temperature gradient of 20℃ / mm. After extrusion, the finished square material is obtained.

[0009] Step S4: Cut the finished material to form a base plate, and perform double-sided mask step etching, which includes three stages. The formed marking system is obtained by mechanical interlocking and metallurgical bonding.

[0010] Preferably, in step S1, the concentration of NaOH in the solution is 5 wt%, and the pH value of the NaOH solution is 12.

[0011] Preferably, in step S1, the obtained fragments are classified according to their particle size as follows:

[0012] Fragments A with a particle size smaller than 1 mm;

[0013] Fragments B with a particle size of 1-3 mm;

[0014] Fragments C with a particle size of 3-4 mm.

[0015] Preferably, in step S1, the ultrasonic cleaning frequency is 40 kHz and the power density is 1.5 W / cm². 2 .

[0016] Preferably, in step S2, the initial pressurization rate is 50 MPa / min, up to 150 MPa, then reduced to 10 MPa / min and gradually increased to 300 MPa, at which point the pressurization is stopped and maintained at 300 MPa for 8 minutes.

[0017] Preferably, in step S2, during the depressurization process, after each 50 MPa reduction, the pressure is maintained for 1 minute, and then reduced by another 50 MPa and maintained for 1 minute to prevent the billet from cracking.

[0018] Preferably, in step S3, the extrusion ratio of the horizontal hydraulic extruder is set to 30:1, and the extrusion rate is 0.8 mm / s.

[0019] Preferably, in step S3, 1 wt% Al-Mg alloy powder is added during extrusion.

[0020] Preferably, in step S4, when performing double-sided mask step etching, a 25μm thick blue dry film is coated on the circuit layer for protection, UV exposure and development are performed, a 30μm anti-etching dry film is applied to the aluminum substrate, an acidic etching solution is used to form a groove with a depth of 50±5μm, and a 5μm copper layer is electroplated at the bottom of the groove as a nickel-gold adhesion substrate. The acidic etching solution is a mixture of HCl and H3PO4.

[0021] Preferably, in step S4, in stage 1, the etching rate is 3 μm / min at 40°C to form an initial groove; in stage 2, the temperature is increased to 55°C and the rate is 6 μm / min to perform lateral groove expansion; in stage 3, the temperature is decreased to 45°C and the rate is 1 μm / min, the groove wall is trimmed, a 2 μm nickel layer is chemically deposited, a 0.05 μm gold layer is deposited using the displacement method, and a heat treatment is performed at 500°C for 10 min to allow the metal layer to form a diffusion bond with the substrate.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. This invention achieves a waste utilization rate of over 95% and improves mechanical properties by 30% through multi-level ratio of fragments and synthetic metal powder design, thereby overcoming the difficulty of non-recyclable reinforced composite materials. The process innovatively divides the fragments into three levels according to particle size: ultrafine fragments fill micropores, medium fragments form the matrix skeleton, and coarse fragments provide reinforcement support. The three are optimized and mixed in a mass ratio of 75:20:5 to obtain an aluminum substrate, realizing the recycling of edge waste.

[0024] 2. This invention uses a double-sided blue adhesive mask process and chemical layer etching technology to directly form microgrooves with a depth of 50μm on an aluminum substrate, and fills them with nickel-gold alloy to form a permanent mark. The new method achieves the same lifespan for the mark and the substrate while maintaining the integrity of the substrate, and solves the problems of easy peeling and poor temperature resistance that exist in ink printing or laser marking. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1:

[0027] The manufacturing process of aluminum substrates includes the following steps:

[0028] Step S1: Ultrasonic cleaning with NaOH solution at 60℃ for 15 minutes, followed by soaking the waste in 10 vol% nitric acid solution for 5 minutes, then three-stage countercurrent rinsing, and feeding the waste into a jaw crusher to accurately classify the obtained fragments according to particle size:

[0029] Fragment A (<1mm): Airflow sorting, accounting for 75%, used to fill the gaps between coarse fragments;

[0030] Fragment B (1-3mm): Vibrating screen, accounting for 20%, forming the matrix skeleton;

[0031] Fragment C (3-4mm): Beveled roll selection, accounting for 5%, provides macroscopic reinforcement frame;

[0032] The graded fragments were mixed with synthetic metal powder at a ratio of 70%, 25%, and 5%, as shown in the table below.

[0033] Table 1. Composition of the synthesized metal powder in Example 1

[0034]

[0035] Step S2: The mixed material is isotropically pressurized using an oil-medium cold isostatic press to promote particle rearrangement and mechanical interlocking, forming a preform. Step-by-step pressure relief is used during pressure release.

[0036] Step S3: The billet is heated to 485°C at a rate of 10°C / min using a horizontal hydraulic extruder and held at that temperature for 2 hours. The extrusion cylinder temperature is set to 400°C and the die holder temperature is set to 410°C, forming a temperature gradient of 20°C / mm. After extrusion, the finished square material is obtained.

[0037] Step S4: Cut the finished material to form a base plate, and perform double-sided mask step etching, which includes three stages. The formed marking system is obtained by mechanical interlocking and metallurgical bonding.

[0038] Example 2:

[0039] The manufacturing process of aluminum substrates includes the following steps:

[0040] Step S1: Ultrasonic cleaning with NaOH solution at 60℃ for 15 minutes, followed by soaking the waste in 10 vol% nitric acid solution for 5 minutes, then three-stage countercurrent rinsing, and feeding the waste into a jaw crusher to accurately classify the obtained fragments according to particle size:

[0041] Fragment A (<1mm): Airflow sorting, accounting for 75%;

[0042] Fragment B (1-3mm): Vibrating sieve, accounting for 20%;

[0043] Fragment C (3-4mm): 5% by inclined roller selection;

[0044] The graded fragments were mixed with synthetic metal powder at a ratio of 75%, 20%, and 5%, as shown in the table below.

[0045] Table 2. Composition of the synthesized metal powder in Example 2

[0046]

[0047] Step S2: The mixed material is isotropically pressurized using an oil-medium cold isostatic press to promote particle rearrangement and mechanical interlocking, forming a preform. Step-by-step pressure relief is used during pressure release.

[0048] Step S3: The billet is heated to 485°C at a rate of 10°C / min using a horizontal hydraulic extruder and held at that temperature for 2 hours. The extrusion cylinder temperature is set to 400°C and the die holder temperature is set to 410°C, forming a temperature gradient of 20°C / mm. After extrusion, the finished square material is obtained.

[0049] Step S4: Cut the finished material to form a base plate, and perform double-sided mask step etching, which includes three stages. The formed marking system is obtained by mechanical interlocking and metallurgical bonding.

[0050] Example 3:

[0051] Compared with Example 2, this example differs only in step S1; the remaining steps are the same, as follows:

[0052] Step S1: Ultrasonic cleaning with NaOH solution at 60℃ for 15 minutes, followed by soaking the waste material in 10 vol% nitric acid solution for 5 minutes, and then three-stage countercurrent rinsing. The obtained fragments are then precisely classified according to particle size.

[0053] Fragment A (<1mm): Airflow sorting, accounting for 80%;

[0054] Fragment B (1-3mm): Vibrating sieve, accounting for 15%;

[0055] Fragment C (3-4mm): 5% by inclined roller selection;

[0056] The waste material is fed into a jaw crusher, and the graded fragments are mixed with synthetic metal powder in a ratio of 80%, 15%, and 5%, as shown in the table below.

[0057] Table 3. Composition of the synthesized metal powder in Example 3

[0058]

[0059] Example 4:

[0060] Compared with Example 3, this example differs only in step S1; the remaining steps are the same, as detailed below:

[0061] The obtained fragments are precisely classified according to their particle size:

[0062] Fragment A (<1mm): Airflow sorting, accounting for 70%;

[0063] Fragment B (1-3mm): Vibrating sieve, accounting for 20%;

[0064] Fragment C (3-4mm): sloping roller selection, accounting for 10%;

[0065] The graded fragments and synthetic metal powder were mixed evenly at a ratio of 70%, 20%, and 10%, as shown in the table below;

[0066] Table 4. Composition of the synthesized metal powder in Example 4

[0067]

[0068] Example 5:

[0069] Compared with Example 4, this example differs only in step S1; the remaining steps are the same, as follows:

[0070] The obtained fragments are precisely classified according to their particle size:

[0071] Fragment A (<1mm): Airflow sorting, accounting for 70%;

[0072] Fragment B (1-3mm): Vibrating sieve, accounting for 15%;

[0073] Fragment C (3-4mm): sloping roll separation, accounting for 15%;

[0074] The graded fragments and synthetic metal powder were mixed evenly at a ratio of 70%, 15%, and 15%, as shown in the table below;

[0075] Table 5. Composition of the synthesized metal powder in Example 5

[0076]

[0077] Example 6:

[0078] Compared with Example 5, this example differs only in step S1; the remaining steps are the same, as detailed below:

[0079] The obtained fragments are precisely classified according to their particle size:

[0080] Fragment A (<1mm): Airflow sorting, accounting for 75%;

[0081] Fragment B (1-3mm): Vibrating sieve, accounting for 20%;

[0082] Fragment C (3-4mm): 5% by inclined roller selection;

[0083] The graded fragments and synthetic metal powder were mixed evenly at a ratio of 70%, 15%, and 15%, as shown in the table below;

[0084] Table 6. Composition of the synthesized metal powder in Example 6

[0085]

[0086] Experiment Implementation 1:

[0087] Sample plates were cut from square materials prepared in Examples 1 to 7 using an existing aluminum substrate (alloy powder ratio: 70%:20%:10%). The parallel section width of the sample was 12.5 mm, the gauge length was 50 mm, and the thickness was the same as the original aluminum substrate, 3 mm. The sample surface was sanded along the stretching direction to remove wire cutting marks, and then the sample was cleaned with alcohol. The sample was placed in a universal testing machine, and the two ends of the sample were clamped with wedge clamps. Tension was applied at a set speed of 5 mm / min, and the load-displacement curve was recorded in real time. The extensometer was used to measure the deformation in the elastic stage and the minute deformation. The elastic modulus and yield strength were calculated. When the load reached the yield point, the extensometer was removed, and the sample was stretched until it broke. The fracture load and elongation after fracture were recorded. The tensile strength was calculated using the maximum load, the load at fracture, and the displacement. The experimental results are shown below:

[0088] Table 7. Comparison of Results from Experiment 1

[0089]

[0090] As shown in the table, the tensile strength in Example 1 reached 285 MPa, which is 30% higher than that of the prior art. When the proportion of fragment A is 70%, the filling effect is the best, which promotes sintering densification. Therefore, the synergistic effect of 6061 alloy powder (low temperature liquid phase promoter) and fragment A is significant. When the proportion of fragment B exceeds 20%, such as 15% in Example 3, the strength of the aluminum substrate begins to decrease. When the proportion of Al-Mg alloy powder exceeds 10%, the interface activation effect is saturated, and the strength improvement is limited.

[0091] In Example 6, the 6061 alloy powder was reduced to 60%, and the Al-Mg alloy powder was increased to 20%. The strength decreased but was still higher than that of the prior art. This indicates that the interfacial activation effect of the Al-Mg alloy powder can partially compensate for the significant reduction of the 6061 alloy powder. Moreover, it is necessary to balance the ratio of the low-temperature liquid phase promoter 6061 and the interfacial activator Al-Mg. By precisely controlling the particle size classification of the fragments and the functional ratio of the alloy powder, the strength of the aluminum substrate can be significantly improved. Therefore, the optimal solution is the ratio of Example 1, which has a 30% increase in tensile strength compared with the prior art, and has significant technical advantages.

[0092] Example 7:

[0093] A method for manufacturing an aluminum substrate, the method comprising the following steps:

[0094] Step S1: Using a NaOH solution with pH 12 at 60°C, ultrasonically at a frequency of 40 kHz and a power density of 1.5 W / cm³. 2The waste material was ultrasonically cleaned for 15 minutes to thoroughly remove cutting oil and organic contaminants from its surface, ensuring the cleaning waves penetrated the microporous solution. The NaOH concentration in the solution was 5 wt%. Afterward, the waste material was drained and then soaked in a 10 vol% nitric acid solution at room temperature for 5 minutes to dissolve the surface oxide layer and increase surface energy. The Cl- content was strictly controlled to be <50 ppm to prevent subsequent stress corrosion. A three-stage countercurrent rinsing process was then performed with deionized water at 25°C to achieve a resistivity >15 MΩ·cm and a residual ion content <10 ppm. The cleaned waste material was then rapidly cooled in a -196°C liquid nitrogen environment for 30 minutes, utilizing the difference in thermal expansion coefficients between 6061 aluminum and SiCp (ΔCTE = 4.5 × 10⁻⁶). -6 / K) induces micro-stress, reducing crushing energy consumption by 40%, and then the waste is fed into a jaw crusher to obtain irregular fragments with a particle size ≤4mm;

[0095] The obtained fragments are precisely classified according to their particle size:

[0096] Fragment A (<1mm): Airflow sorting, accounting for 75%, used to fill the gaps between coarse fragments;

[0097] Fragment B (1-3mm): Vibrating screen, accounting for 20%, forming the matrix skeleton;

[0098] Fragment C (3-4mm): Beveled roll selection, accounting for 5%, provides a macroscopically reinforced framework;

[0099] Table 8. Composition of the synthesized metal powder in Example 7

[0100]

[0101] The graded fragments and synthetic metal powder are mixed evenly according to the above proportions;

[0102] Step S2: Using an oil-medium cold isostatic press, the mixed materials are isotropically pressurized through the hydraulic system of the equipment. The initial pressurization rate is 50 MPa / min, up to 150 MPa, then reduced to 10 MPa / min and slowly increased to 300 MPa. Pressurization is stopped and maintained at 300 MPa for 8 minutes to promote particle rearrangement and mechanical interlocking to form a green body. When depressurizing, a stepped depressurization is used. After each 50 MPa reduction, the pressure is maintained for 1 minute, then reduced by another 50 MPa and maintained for 1 minute to prevent the green body from cracking.

[0103] After molding, the performance indicators of the green body are tested to ensure that the density uniformity reaches ±0.15g / cm³. 3The radial compressive strength reaches 85MPa and the open porosity is less than 7%. At this time, a triple interlocking structure is formed inside the billet. Macroscopically, coarse fragments C and alloy powder form a truss support, and ultrafine powder is embedded on the surface of medium fragments B to form a pinning effect. Microscopically, the nano Al2O3 film formed by fragment A and 6061 alloy powder covers the fragment interface and improves the bonding strength.

[0104] Step S3: A horizontal hydraulic extruder equipped with a zoned temperature control mold system is used. The billet is heated to 485°C at a rate of 10°C / min and held at that temperature for 2 hours to allow Mg to diffuse fully. The extrusion cylinder temperature is set to 400°C and the die holder temperature is set to 410°C, forming a temperature gradient of 20°C / mm. The extrusion ratio is set to 30:1 and the extrusion rate is 0.8mm / s to ensure that the degree of dynamic recrystallization is >90%. After extrusion, the finished square material is obtained.

[0105] During the extrusion process, 1 wt% Al-Mg alloy powder is added to generate Mg vapor at 480℃ to reduce the Al2O3 film and break the nano oxide layer; the holding time at 480℃ is precisely controlled to be ≤2 hours to prevent excessive formation of Al4C3 brittle phase. During the extrusion process, SiCp is oriented under shear force to form a heat conduction path.

[0106] Step S4: Cut the finished material to form a substrate, perform double-sided mask step etching, apply a 25μm thick blue dry film for circuit layer protection, perform UV exposure and development, apply a 30μm anti-etching dry film to the aluminum substrate, form a 45μm deep groove using an acidic etching solution, and electroplate a 5μm copper layer at the bottom of the groove as a nickel-gold adhesion substrate. The acidic etching solution is a mixture of HCl and H3PO4, where HCl:H3PO4 = 1:3. A step etching process is used, with stage 1 etching at 40℃ at a certain rate. At a rate of 3 μm / min, an initial groove is formed. In stage 2, the temperature is increased to 55°C at a rate of 6 μm / min for lateral groove expansion. In stage 3, the temperature is decreased to 45°C at a rate of 1 μm / min. After trimming the groove wall, a 2 μm nickel layer is chemically deposited, followed by a 0.05 μm gold layer deposited using a displacement method to achieve a reflectivity >85%. The metal layer is then heat-treated at 500°C for 10 min to allow diffusion bonding between the metal layer and the substrate. The final marking system is obtained by combining mechanical interlocking and metallurgical bonding to produce the aluminum substrate.

[0107] Example 8:

[0108] Compared with Example 7, this example differs only in step S4; the remaining steps are the same, as detailed below:

[0109] Step S4: Cut the finished material to form a base plate, perform double-sided mask step etching, apply a 25μm thick blue dry film for circuit layer protection, perform UV exposure and development, apply a 30μm anti-etching dry film to the aluminum base, use acidic etching solution to form a 50μm deep groove, and electroplate a 5μm copper layer at the bottom of the groove as a nickel-gold adhesion substrate. The acidic etching solution is a mixture of HCl and H3PO4, where HCl:H3PO4 = 1:3. A step etching process is used. In stage 1, the etching rate is 3μm / min at 40℃ to form the initial groove. In stage 2, the temperature is increased to 55℃ and the rate is 6μm / min to expand the groove laterally. In stage 3, the temperature is decreased to 45℃ and the rate is 1μm / min. After trimming the groove wall, a 2μm nickel layer is chemically deposited, a 0.05μm gold layer is deposited using the displacement method, and a heat treatment is performed at 500℃ for 10min.

[0110] Example 9:

[0111] Compared with Example 8, this example uses an acidic etching solution to form a groove with a depth of 55 μm, while the other steps are the same.

[0112] Experiment Implementation 2:

[0113] Samples of existing aluminum substrates and finished products obtained in Examples 7, 8 and 9 were taken as samples. The sample size was uniformly 100mm×100mm×2mm. The samples were placed in a constant temperature chamber with the temperature set at 150℃ and the exposure time was 24 hours. The area of ​​label peeling (unit: %) and the color change ΔE value were evaluated.

[0114] Alternate between high and low temperatures, with a high temperature of 150℃ and a low temperature of -40℃, for 50 cycles, with the high and low temperature alternation occurring once every hour;

[0115] The samples were placed in a high-temperature aging chamber at 150°C and checked every 24 hours for 240 hours. The integrity rate of the markings (unit: %) and the wear of the marking edges (unit: μm) were tested. A control group test for laser marking was conducted, and the temperature resistance and service life data were recorded. The experimental results are shown in the table below.

[0116] Table 9. Comparison of Results from Experiment Implementation 2

[0117]

[0118] Example 7 performed best, with only 0.5% of the marking area detached after high-temperature storage and minimal color change (ΔE = 1.2), approaching the level of laser marking (ΔE = 0.8). Moreover, after 240 hours of accelerated aging, Example 7 achieved a 98% integrity rate and a wear of 2μm, which is better than Examples 8 and 9, but slightly lower than laser marking. At an etching depth of 45μm, the mechanical and metallurgical bonding between the marking and the substrate was optimal, with the best temperature resistance and lifespan. However, when the etching depth was adjusted to 55μm, excessive depth led to stress concentration, brittle marking edges, and a significant increase in detachment area and wear. Laser marking has better temperature resistance (ΔE = 0.8) and a longer lifespan (>8000h), but it is more expensive and suitable for high-precision applications. The 45μm etching in Example 7 is closest to laser marking technology in terms of temperature resistance and lifespan, and is less expensive, making it suitable for large-scale industrial applications. Laser marking remains the preferred choice for high-precision marking, but the technical solution provided by Example 7 is more cost-effective. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing an aluminum substrate, characterized in that: The method includes the following steps: Step S1: Use NaOH solution to perform ultrasonic cleaning at 60℃ for 15 minutes, then soak the waste in 10 vol% nitric acid solution for 5 minutes, and then perform three-stage countercurrent rinsing. Send the waste into a jaw crusher and mix the graded fragments with synthetic metal powder in a ratio of 70%, 25%, and 5%. Step S2: The mixed materials are isotropically pressurized using an oil-medium cold isostatic press to promote particle rearrangement and mechanical interlocking, forming a preform. Step-by-step pressure relief is used during pressure release. Step S3: The billet is heated to 480±5℃ at a rate of 10℃ / min using a horizontal hydraulic extruder and held at that temperature for 2 hours. The extrusion cylinder temperature is set to 400~420℃ and the die holder temperature is set to 410~450℃, forming a temperature gradient of 20℃ / mm. After extrusion, the finished square material is obtained. Step S4: Cut the finished material to form a base plate, and perform double-sided mask step etching, which includes three stages. The formed marking system is obtained by mechanical interlocking and metallurgical bonding.

2. The manufacturing method of an aluminum substrate according to claim 1, characterized in that: In step S1, the concentration of NaOH in the solution is 5 wt%, and the pH value of the NaOH solution is 12.

3. The manufacturing method of an aluminum substrate according to claim 1, characterized in that: In step S1, the obtained fragments are classified according to their particle size as follows: Fragments A with a particle size smaller than 1 mm; Fragments B with a particle size of 1-3 mm; Fragments C with a particle size of 3-4 mm.

4. The manufacturing method of an aluminum substrate according to claim 1, characterized in that: In step S1, the ultrasonic cleaning frequency is 40kHz and the power density is 1.5W / cm². 2 .

5. The manufacturing method of an aluminum substrate according to claim 1, characterized in that: In step S2, the initial pressurization rate is 50 MPa / min, up to 150 MPa, then reduced to 10 MPa / min and gradually increased to 300 MPa, at which point the pressurization is stopped and maintained at 300 MPa for 8 minutes.

6. The manufacturing method of an aluminum substrate according to claim 1, characterized in that: In step S2, during the depressurization process, after each 50 MPa decrease, the pressure is maintained for 1 minute, and then the pressure is decreased by another 50 MPa and maintained for 1 minute.

7. The manufacturing method of an aluminum substrate according to claim 1, characterized in that: In step S3, the extrusion ratio of the horizontal hydraulic extruder is set to 30:1, and the extrusion rate is 0.8 mm / s.

8. The manufacturing method of an aluminum substrate according to claim 1, characterized in that: In step S3, 1 wt% Al-Mg alloy powder is added during extrusion.

9. The manufacturing method of an aluminum substrate according to claim 1, characterized in that: In step S4, when performing double-sided mask step etching, a 25μm thick blue dry film is coated on the circuit layer for protection, UV exposure and development are performed, a 30μm anti-etching dry film is attached to the aluminum substrate, an acidic etching solution is used to form a groove with a depth of 50±5μm, and a 5μm copper layer is electroplated at the bottom of the groove as a nickel-gold adhesion substrate. The acidic etching solution is a mixture of HCl and H3PO4.

10. The manufacturing method of an aluminum substrate according to claim 1, characterized in that: In step S4, in stage 1, the etching rate is 3 μm / min at 40°C to form an initial groove. In stage 2, the temperature is increased to 55°C and the rate is 6 μm / min to perform lateral groove expansion. In stage 3, the temperature is decreased to 45°C and the rate is 1 μm / min. After the groove wall is trimmed, a 2 μm nickel layer is chemically deposited, a 0.05 μm gold layer is deposited using the displacement method, and a heat treatment is performed at 500°C for 10 min to allow the metal layer to form a diffusion bond with the substrate.

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