Forming method of high-thermal-conductivity and high-electric-conductivity aluminum alloy powder rolled sheet

Abstract

The invention discloses a high-thermal-conductivity and high-electric-conductivity aluminum alloy powder rolled sheet forming method which comprises the steps that aluminum alloy powder serves as a powder raw material, and a plate-shaped blank is formed in the mode that the powder raw material is extruded; and heating and sintering the blank, and then sequentially carrying out hot rolling, cold rolling and rolling to obtain the aluminum alloy medium plate material with high thermal conductivity and electric conductivity. According to the forming method for the high-thermal-conductivity and high-electric-conductivity aluminum alloy powder rolled sheet, the particle size of the aluminum alloy powder is accurately controlled to be 5-60 microns in the aspect of raw material selection, a good forming basis is ensured, nanoscale particles and micron particles can be flexibly selected to be compounded, gaps of the micron particles are filled with the nanoscale particles, and the compactness and performance of the material are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of powder metallurgy, and particularly relates to a method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin plate. Background Art

[0002] In the field of modern electronic device manufacturing, especially in mobile phone manufacturing, the performance requirements for the middle plate material of mobile phones are becoming increasingly stringent. As a key component of the internal structure of a mobile phone, the middle plate of the mobile phone not only needs to have good mechanical strength to support and protect internal precision electronic components, but also needs to have excellent thermal conductivity and electrical conductivity to meet the requirements of efficient heat dissipation and stable electrical connection of the mobile phone. Aluminum alloys and their composite materials have become ideal material choices for mobile phone middle plate manufacturing due to their low density, relatively high strength, and good processing performance. Among them, the processing technology of aluminum thin plates is crucial. Currently, the common processing methods of aluminum thin plates mainly include the casting-rolling process and the traditional powder metallurgy process. The casting-rolling process melts aluminum and aluminum alloy raw materials through a melting furnace, then casts them into ingots, and finally obtains aluminum thin plates with the required thickness through a series of rolling processes such as hot rolling blooming and cold rolling. However, this process has many drawbacks. During the casting process, due to the contact between the aluminum alloy liquid and air, defects such as oxidation inclusions are easily generated, which will seriously affect the internal quality of the aluminum thin plate. At the same time, too many rolling passes not only make the process flow longer and the processing time-consuming, but also make it difficult to uniformly unify the rolling quality, and its surface quality and dimensional accuracy are poor. The traditional process has limited control ability for the surface quality and dimensional accuracy of aluminum thin plates during the processing process. During the rolling process, due to insufficient equipment accuracy and process control, problems such as scratches on the surface of the plate and uneven thickness are likely to occur, which are serious defects for the manufacturing of mobile phone middle plates with extremely high requirements for surface quality and dimensional accuracy.

[0003] In addition, in the mobile phone industry, in order to achieve the thin and light design of mobile phones while ensuring their reliability and durability, the lightweight and thinning improvement of aluminum thin plate mobile phone middle plates while taking into account or improving strength has become a key requirement.

[0004] During the lightweight and thinning process of existing aluminum thin plate mobile phone middle plates, problems such as deformation and damage often occur due to a decrease in strength. On the one hand, as the thickness decreases, the load-bearing capacity of the material decreases; on the other hand, the aluminum thin plates obtained by traditional processing techniques themselves have insufficient strength and are difficult to withstand the stress after thinning.

[0005] The present invention effectively solves this contradiction through a series of improvement measures. During the raw material treatment and processing, means such as refining grains, enhancing interface bonding, and improving density significantly improve the strength of aluminum thin sheets. Even when a lightweight thinning design is carried out, it can still ensure that the middle plate of the mobile phone has sufficient strength to meet the mechanical property requirements of the mobile phone under various usage scenarios, providing strong technical support for the development of thinner and lighter mobile phones. Summary of the Invention

[0006] The object of the present invention is to overcome the defects existing in the prior art and provide a method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin sheet.

[0007] To achieve the above object, the technical solution of the present invention is as follows: A method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin sheet, including a powder raw material using aluminum alloy powder, and forming a plate-shaped blank by extruding the powder raw material; heating and sintering the blank, and then successively passing through hot rolling, cold rolling, and coiling to obtain a high thermal conductivity and electrically conductive aluminum alloy middle plate material.

[0008] Further, the particle size of the powder raw material is 5 - 60 microns, the extrusion method is rolling, and the initial rolling thickness is controlled at 1 - 3 mm.

[0009] Further, the powder raw material is mixed in a way of compounding nano-sized and micron-sized particles, so that during the initial rolling, the nano-sized particles are filled in the gaps between the micron-sized particles.

[0010] Further, the powder raw material also includes silicon carbide powder, the volume proportion of the added silicon carbide powder is 20 - 30%, and it also includes pretreatment of the powder raw material.

[0011] Further, the pretreatment method includes acid etching treatment, which is used to remove surface impurities, improve the surface activity of the powder, and is beneficial to the bonding between powders in subsequent processes. Place the powder raw material in an acid-resistant container, add acid solution for soaking treatment, and then wash with deionized water until neutral and dry.

[0012] Further, the pretreatment includes adding a weighed surfactant to the powder raw material and fully mixing in a mixing device; the addition amount of the surfactant is 0.5 - 1% of the mass of the powder raw material, so that the surfactant uniformly wraps the surface of the powder raw material. During the powder rolling and sintering processes, it helps to improve the fluidity and formability of the powder, and improve the bonding force between powders, and is applicable to the mixed system of aluminum alloy powder and silicon carbide powder.

[0013] Further, the pretreatment includes treatment with a silane coupling agent for surface modification of the silicon carbide powder, improving its wettability with the aluminum alloy powder and the interfacial bonding strength, being applicable to the sintering and subsequent hot rolling and cold rolling processes, and effectively improving the performance of the composite material; the silane coupling agent is formulated into a solution with a specific concentration, and the powder raw materials are added thereto, stirred evenly and then soaked, and after taking out, drying treatment is carried out.

[0014] Further, surface modification is carried out on the silicon carbide powder, and a metal aluminum coating is deposited on the surface of the silicon carbide powder by chemical vapor deposition to improve the wettability between the silicon carbide and the aluminum alloy powder and improve the interfacial bonding strength.

[0015] Further, it also includes micro-arc oxidation treatment on the surface of the medium plate material to form a ceramic oxide film on its surface, improving the wear resistance, corrosion resistance and surface hardness of the medium plate material.

[0016] Further, it also includes electroless metal plating treatment on the surface of the medium plate material to form a metal coating on the surface of the medium plate material.

[0017] The advantages and beneficial effects of the present invention are as follows: In the method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin plate of the present invention, in terms of raw material selection, the particle size of the aluminum alloy powder is accurately controlled within 5 - 60 microns, ensuring a good forming foundation, and the compounding of nano-scale and micron-scale particles can be flexibly selected, allowing nano-scale particles to fill the gaps between micron-scale particles, effectively improving the material density and performance. When silicon carbide powder is introduced to further enhance the material strength, it can effectively reduce the thickness of the mobile phone while maintaining the strength. Heating and sintering promote the fusion of the powder, hot rolling improves the material structure, cold rolling improves the sheet accuracy, and coiling ensures the integrity of the product. The entire method can efficiently produce aluminum alloy medium plate materials with both high thermal conductivity and electrical conductivity, good mechanical properties and high precision through precise control of the parameters of each step, meeting the requirements for high-performance aluminum alloy sheets in multiple fields. Specific Embodiments

[0018] The following combines examples to further describe the specific embodiments of the present invention. The following examples are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0019] Example 1: A method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin plate includes powder raw materials taking aluminum alloy powder as the raw material, forming a plate-shaped blank by extruding the powder raw materials; heating and sintering the blank, and then successively passing through hot rolling, cold rolling, and coiling to obtain a high thermal conductivity and electrically conductive aluminum alloy medium plate material.

[0020] Further, the particle size of the powder raw material is 5 - 60 microns, and the extrusion method is rolling, with the initial rolling thickness controlled at 1 - 3 mm.

[0021] In this embodiment, a single aluminum alloy powder is used as the raw material for processing. Specifically, in the raw material preparation stage: an aluminum alloy powder is selected, and its particle size is in the range of 5 - 60 microns. A vibrating screen is used for screening to filter out impurities such as large particles.

[0022] It is possible to perform pretreatment on the powder raw material to improve the surface properties of the powder. Specifically, the aluminum alloy powder is immersed in a dilute hydrochloric acid solution with a mass fraction of 1% - 3%, the temperature is controlled at 30 - 40 °C, and the immersion time is 15 - 30 minutes. After immersion, it is repeatedly rinsed with deionized water until neutral, and then the powder is dried. The treated powder is placed in a vacuum drying oven, the drying temperature is set at 80 - 100 °C, and the drying time is 3 - 5 hours to remove the moisture in the powder and avoid defects in subsequent processes. A powder rolling mill is used to roll the powder raw material to form a plate-shaped blank. In actual use, in addition to using a double-roll powder rolling mill, a continuous feeding machine can also be used for feeding, and then a rolling roller is used for rolling and forming; before the initial rolling, ensure that the surface of the rolling roller is smooth, without wear and impurity attachment. Set the rolling roller speed. During the initial rolling, the upper and lower rolling roller speeds are the same, controlled at 5 - 10 revolutions per minute to ensure that the powder has enough time to fill the gap between the rolling rollers and be initially compacted during rolling. Adjust the gap between the rolling rollers, and the initial rolling thickness is controlled at 1 - 3 mm.

[0023] Start the rolling mill and start rolling. During the rolling process, closely observe the forming situation of the blank to ensure that the thickness of the blank is uniform and there are no defects such as holes and cracks. If quality problems of the blank are found, stop the machine in time to adjust parameters such as the powder feeding speed, rolling roller speed, or gap. As a sintering method: through induction heating sintering, the rolled plate-shaped blank is placed in an induction heating device, which consists of an induction coil, a power control system, etc., and the heating power can be controlled. The heating power is adjusted according to the size and mass of the blank. Exemplarily, the heating power is between 5 - 20 kW; the heating rate is controlled at 5 - 15 °C per minute. Slowly increasing the temperature helps to avoid defects such as cracks in the blank due to excessive thermal stress; the sintering temperature is set between 500 - 600 °C. At this temperature, the aluminum alloy powder particles can fully diffuse and bond with each other, improving the density and strength of the blank; the holding time is 1 - 3 hours to ensure the homogenization of the internal structure of the blank. During the heating process, a certain amount of protective gas is introduced, and argon can be used to prevent the aluminum alloy blank from oxidizing at high temperatures.

[0024] As another sintering method: use a vacuum sintering furnace to place the rolled plate blanks on the carrier of the sintering furnace steadily, keeping a certain distance between the blanks to avoid mutual adhesion. During sintering, the vacuum degree in the furnace is drawn to 10 -3 -10 - 4 Pa, in order to reduce the impact of the gas in the furnace on the sintering process and prevent the oxidation of the aluminum alloy. The heating rate is controlled at 5-10℃ / minute. The temperature is raised to 550-650℃, and the temperature can be fine-tuned according to the specific composition of the aluminum alloy. For example, 6061 aluminum alloy can be selected at 600℃, and the holding time is 60-90 minutes, so that the powder particles can be fully diffused and fused, and the density of the blank is improved. The sintered billet is taken out and transferred to the hot rolling equipment for hot rolling. The hot rolling temperature is controlled between 400-500℃, which can ensure that the aluminum alloy material has good plasticity and avoid overheating of the material structure due to excessive temperature.

[0025] Since the thin plate-shaped billet is directly formed by powder processing, its thickness is close to the predetermined target thickness, so only a few rolling passes are required to reach the target thickness. During hot rolling, the reduction amount of each rolling is controlled between 10% and 30%, and the number of rolling passes is determined according to the thickness of the billet and the thickness requirements of the final product, which is generally less than 3 times. Through multiple hot rolling passes, the density and strength of the material are further improved, and the internal structure of the material is improved to make it more dense and uniform. The hot rolling speed is controlled at 2-10 meters / minute, which ensures production efficiency while ensuring that the material can be fully deformed and recrystallized during the hot rolling process.

[0026] After the hot-rolled aluminum alloy sheet cools to room temperature, it is cold-rolled. The purpose of cold rolling is to further improve the surface quality and dimensional accuracy of the sheet, while increasing the strength and hardness of the material. The cold rolling speed is controlled at 1-5 meters per minute. The lower speed helps to ensure the surface quality and dimensional accuracy of the sheet. During the cold rolling process, the sheet can be properly lubricated as needed to reduce friction and improve the surface quality of the sheet.

[0027] Taking 6061 aluminum alloy powder as an example, its main components are aluminum, silicon, magnesium and other elements, and the powder particle size is between 5-60 microns.

[0028] The aluminum alloy powder was evenly spread on the feeding device of the rolling equipment, and the initial rolling was carried out at a speed of 3 m / min and a rolling pressure of 10 MPa to obtain a plate-shaped billet with a thickness of 2 mm.

[0029] The blank was placed in an induction heating device, and argon was introduced as a protective gas at a flow rate of 1 cubic meter per hour. The heating power was set to 10 kW, the heating rate was set to 10°C per minute, the sintering temperature was set to 550°C, and the holding time was set to 2 hours.

[0030] The sintered blank is quickly transferred to a hot rolling equipment and hot rolled at 450 °C. Four passes of rolling are adopted, with a reduction of 20% each time and a hot rolling speed of 5 m / min.

[0031] After the hot rolled sheet is cooled to room temperature, cold rolling is carried out. Three passes of rolling are adopted, with a reduction of 10% each time and a cold rolling speed of 3 m / min.

[0032] Finally, the cold rolled aluminum alloy thin sheet is coiled to obtain a high thermal conductivity and conductive aluminum alloy thin sheet product. After testing, the thermal conductivity and electrical conductivity of this product both meet the expected requirements, and it has good mechanical properties and surface quality.

[0033] Example 2: The steps of this example are generally the same as those of the previous example, except that in this example, the powder raw materials are mixed with raw materials of different particle size grades, and the powder raw materials are mixed in a way of compounding nanoscale and micron particles, so that during the first rolling, the nanoscale particles are filled in the gaps between the micron particles.

[0034] Specifically, the powder mixing ratio is that the nanoscale powder accounts for 10%-30% and the micron-scale powder accounts for 70%-90%; the raw materials of different particle grades are mechanically stirred and mixed; after mixing, the mixed powder is placed in a vacuum drying oven for drying. Other process controls are the same as those in Example 1.

[0035] Specifically, taking the 6061 aluminum alloy system powder as an example, nanoscale powder with a particle size of 50-200 nm is screened out by centrifugal classification, and micron-scale powder with a particle size of 20-60 μm is screened out by a vibrating screen. The nanoscale powder and the micron-scale powder are mixed in a ratio of 20% and 80%. In a high-energy ball mill, the ball-to-material ratio is 8:1, 0.4% zinc stearate is added as a dispersant, and they are mixed at a speed of 250 revolutions per minute for 5 hours. Use a double-roll powder rolling mill to roll into a medium plate material. Put the blank into an induction heating equipment, the sintering temperature is 550 °C, and the holding time is 1.5 hours. Then it undergoes hot rolling, cold rolling, and coiling.

[0036] Example 3: The difference between this example and Example 1 is that two different powder raw materials are adopted. Specifically, the powder raw materials also include silicon carbide powder, and the volume ratio of the added silicon carbide powder is 20-30%. It also includes the pretreatment of the powder raw materials.

[0037] Selection of powder raw materials: As an implementation method, the selected silicon carbide powder and aluminum alloy powder are both micron-scale, and raw materials with a particle size in the range of 5-60 μm are selected.

[0038] As another embodiment, referring to Embodiment 2, both the silicon carbide powder and the aluminum alloy powder are mixed and used with raw materials of two different particle size grades.

[0039] The volume ratio of the silicon carbide powder is 20 - 30%. By calculating the densities of the two powders and the target volume ratio, the corresponding masses of the aluminum alloy powder and the silicon carbide powder are accurately weighed; after mixing the powders, zinc stearate surfactant is added, and the addition amount of the surfactant is 0.5 - 1% of the mass of the powder raw materials. The weighed surfactant is added to the aluminum alloy powder and the silicon carbide powder in the mixing equipment. A V-type mixer or a high-speed stirring mixer can be used. Taking the use of a V-type mixer as an example, the mixing time is set to 30 - 60 minutes, and the rotation speed is 20 - 40 revolutions per minute; ensure that the surfactant uniformly coats the surface of the powder raw materials, improving the wettability and fluidity between the powders, which is beneficial to the subsequent rolling and sintering processes.

[0040] Specifically, 6061 aluminum alloy powder is selected and screened through a vibrating sieve so that more than 90% of the powder particle sizes are in the range of 20 - 40 microns. After screening the silicon carbide powder, the particle size is in the range of 5 - 60 microns; a double-roll powder rolling mill is used, the rolling force is set to 20 kN, the roll rotation speed is 5 revolutions per minute, the powder feeding speed is 5 kg / h, and the roll gap is adjusted to 2 mm for the first rolling to obtain a plate-shaped blank with a thickness of 2 mm, and the thickness deviation of the blank is controlled within ±0.08 mm. The blank is placed in an induction heating device, and argon is introduced with a flow rate of 1 cubic meter per hour. The heating power is set to 10 kW, the heating speed is 8 °C per minute, the sintering temperature is 600 °C, and the holding time is 1.5 hours. Then hot rolling and cold rolling are carried out, and coiling is performed.

[0041] Embodiment 4: The difference between this embodiment and Embodiment 1 is that a pretreatment step of adding a silane coupling agent is included. Specifically, the silane coupling agent is formulated into a solution with a specific concentration, and the powder raw materials are added thereto, stirred evenly and then soaked, and dried after being taken out.

[0042] The powder selection is specifically as follows: 6061 aluminum alloy powder is selected for the aluminum alloy powder, and the powder particle size range is controlled within 5 - 60 microns. For the silicon carbide powder, silicon carbide powder with uniform particle size is selected, and the particle size is also controlled within 5 - 60 microns. The purity of the silicon carbide powder should be not less than 98% to ensure the performance of the composite material. The volume ratio of the silicon carbide powder is 20 - 30%.

[0043] During pretreatment, KH-550 silane coupling agent can be selected. The silane coupling agent is formulated into a solution with a concentration of 1%-5% (mass fraction), and the solvent can be an ethanol-water mixed solution with a volume ratio of ethanol to water of 3:1-4:1. Specifically, to prepare a 2% concentration silane coupling agent solution, 2 g of silane coupling agent is weighed and added to 98 g of ethanol-water mixed solution, and stirred evenly.

[0044] The weighed aluminum alloy powder and silicon carbide powder are added to the silane coupling agent solution for powder soaking treatment, and the mass ratio of powder to solution is 1:10-1:15. A stirring device is used for stirring, the stirring speed is 100-200 revolutions per minute, and the stirring time is 2-4 hours to ensure that the powder is in full contact with the silane coupling agent.

[0045] During the soaking process, the solution temperature is controlled at 20-30 °C to avoid decomposition of the silane coupling agent due to too high temperature. The soaking time is 2-4 hours to enable the silane coupling agent to fully coat the powder surface.

[0046] After the soaking is completed, the powder is taken out of the solution, and the excess solution is removed by filtration or centrifugation. Then the powder is placed in a vacuum drying oven for drying treatment, the drying temperature is set at 80-120 °C, and the drying time is 3-6 hours until the powder is completely dry.

[0047] Subsequent operations such as rolling, sintering, hot rolling, and cold rolling are the same as those in the foregoing embodiments.

[0048] Example Five: Furthermore, the surface of the silicon carbide powder is modified. The chemical vapor deposition method is used to deposit a metal aluminum coating on the surface of the silicon carbide powder to improve the wettability between the silicon carbide and the aluminum alloy powder and enhance the interfacial bonding strength.

[0049] For the surface modification of the silicon carbide powder, specifically, trimethylaluminum (TMA) is used as the aluminum source gas, and the purity needs to reach more than 99.9%. Argon is used as the carrier gas, and the purity is not less than 99.99%. The selected silicon carbide powder is evenly placed in the reaction boat of the CVD equipment, and the thickness of the powder layer should not be too thick, controlled at 5-10 mm to ensure that the gas can fully contact the powder surface.

[0050] Close the reaction chamber, start the vacuum system, and pump the chamber to a vacuum degree of 10 -3 -10 -4Pa to exclude the impurity gas in the cavity. Turn on the heating system and raise the temperature of the reaction chamber to 300 - 500 °C, with the heating rate controlled at 5 - 10 °C per minute. Introduce argon as the carrier gas, with the flow rate controlled at 100 - 300 sccm (standard cubic centimeters per minute), and stabilize the chamber pressure at 10 - 100 Pa. Introduce trimethylaluminum, the aluminum source gas, at a certain flow rate, with the flow rate controlled at 10 - 50 sccm, and the deposition time is 30 - 60 minutes, so that aluminum atoms are deposited on the surface of the silicon carbide powder to form a metal aluminum coating. The coating thickness can be controlled by the deposition time and the flow rate of the aluminum source gas, generally controlled at 100 - 500 nanometers.

[0051] After the deposition is completed, stop introducing the aluminum source gas, continue to introduce argon, and keep the chamber pressure stable. Lower the chamber temperature to room temperature at a rate of 5 - 10 °C per minute. After the chamber temperature drops to room temperature, open the chamber and take out the surface-modified silicon carbide powder. Put the surface-modified silicon carbide powder and aluminum alloy powder into a three-dimensional motion mixer for mixing. The mixing time is 2 - 4 hours, and the rotation speed is controlled at 10 - 30 revolutions per minute to ensure that the two powders are fully and evenly mixed.

[0052] Subsequent operations such as rolling, sintering, hot rolling, and cold rolling are the same as those in the foregoing embodiments.

[0053] Example Six: On the basis of the foregoing embodiments, it further includes micro-arc oxidation treatment on the surface of the medium plate material to form a ceramic oxide film on its surface, improving the wear resistance, corrosion resistance, and surface hardness of the medium plate material.

[0054] Perform micro-arc oxidation treatment on the medium plate materials processed in the foregoing respective embodiments. Specifically, the electrolyte formula for micro-arc oxidation treatment is: sodium hydroxide 5 - 10 g / L, sodium silicate 10 - 15 g / L, and the additive is glycerol or the like 2 - 5 g / L. Calculate and prepare an appropriate amount of electrolyte according to the area of the processed plate.

[0055] The coiled aluminum alloy medium plate material is cut into appropriate sizes, and the plates are vertically suspended in the micro-arc oxidation tank using fixtures, ensuring that the plates are completely immersed in the electrolyte and there is a certain distance between the plates to avoid mutual influence. Set the micro-arc oxidation parameters: the voltage is controlled at 300 - 400 V, the current density is 5 - 10 A / dm², and the treatment time is 20 - 30 minutes. During the treatment process, turn on the electrolyte circulation system to control the electrolyte temperature at 25 - 35 °C, and maintain the temperature stability through the cooling system. Closely observe the discharge phenomenon on the surface of the plate during the micro-arc oxidation process to ensure the normal progress of the treatment.

[0056] After the micro-arc oxidation treatment is completed, the plate is taken out of the electrolyte and immediately placed in deionized water for cleaning to remove the residual electrolyte on the surface. The cleaning time is 5 - 10 minutes to ensure thorough cleaning. Then the plate is placed in a drying oven, with the drying temperature set at 60 - 80 °C and the drying time of 1 - 2 hours to thoroughly dry the surface of the plate, thereby obtaining a medium-thickness aluminum alloy material with a ceramic oxide film on the surface, which is highly wear-resistant, corrosion-resistant, and has high hardness.

[0057] Example Seven: Based on the foregoing embodiments, it further includes electroless metal plating treatment on the surface of the medium-thickness plate material to form a metal coating on the surface of the medium-thickness plate material.

[0058] The electroless metal plating treatment specifically includes pre-plating treatment, including degreasing, pickling, and activation. Degreasing: The degreasing agent selects a mixed solution of sodium hydroxide and sodium carbonate. The concentration of sodium hydroxide is 20 - 30 g / L, and the concentration of sodium carbonate is 10 - 20 g / L. The degreasing temperature is controlled at 60 - 80 °C, and the degreasing time is 5 - 10 minutes to remove the oil stains on the surface of the plate. Pickling: The degreased plate is rinsed clean with water. The pickling solution selects a sulfuric acid solution with a concentration of 10 - 20% (volume fraction). The pickling temperature is at room temperature, and the pickling time is 1 - 3 minutes to remove the oxide film on the surface of the plate. Activation: The pickled plate is rinsed clean with water again and placed in an activation solution for activation treatment. The activation solution selects a hydrofluoric acid solution with a concentration of 1 - 3% (volume fraction). The activation temperature is at room temperature, and the activation time is 0.5 - 2 minutes to improve the activity of the surface of the plate and enhance the bonding force between the coating and the substrate.

[0059] Taking copper plating as an example, copper sulfate is selected as the main salt, and its concentration is controlled at 15 - 25 g / L. Copper sulfate provides copper ions in the plating solution. Sodium hypophosphite is used as a reducing agent, and its concentration is set at 20 - 30 g / L. Sodium hypophosphite can reduce copper ions in the plating solution to metallic copper in the plating solution. Potassium sodium tartrate is used as a complexing agent, and its concentration is 30 - 50 g / L. The complexing agent can form a stable complex with copper ions, prevent copper ions from being prematurely reduced in the plating solution, and at the same time adjust the stability of the plating solution and the pH buffering ability, so that the plating solution maintains a stable working state for a long time. Sodium hydroxide or sulfuric acid is used to adjust the pH value of the plating solution between 9 and 11.

[0060] The activated plate is placed in the electroless plating solution, and the plating solution temperature is controlled at 85 - 95 °C. During the plating process, a stirring device is used to stir the plating solution to make the composition of the plating solution uniform and improve the quality of the coating. After the plating is completed, the plate is taken out of the plating solution, rinsed clean with water, and the residual plating solution on the surface is removed.

[0061] Then the plate is placed in an oven for heat treatment. The heat treatment temperature is 200 - 300 °C, and the holding time is 1 - 2 hours to improve the hardness and corrosion resistance of the coating.

[0062] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A forming method for a high thermal conductivity and conductive aluminum alloy powder rolling thin plate, characterized in that, It includes a powder raw material made of aluminum alloy powder, and a plate-shaped blank is formed by extruding the powder raw material; the blank is heated and sintered, and then successively passed through hot rolling, cold rolling, and coiling to obtain a high thermal conductivity and electrically conductive aluminum alloy medium plate material.

2. A method for forming a high thermal conductivity and conductive aluminum alloy powder rolling thin plate according to claim 1, characterized in that, The particle size of the powder raw material is 5 - 60 microns, and the extrusion method is rolling, with the initial rolling thickness controlled at 1 - 3 mm.

3. A method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin plate according to claim 1, characterized in that, The powder raw material is mixed in a way of compounding nano-scale and micron-sized particles, so that during the initial rolling, the nano-scale particles are filled in the gaps between the micron-sized particles.

4. A method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin plate according to claim 1, characterized in that, The powder raw material also includes silicon carbide powder, and the volume proportion of the added silicon carbide powder is 20 - 30%, and it also includes the pretreatment of the powder raw material.

5. A method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin plate according to claim 4, characterized in that, The pretreatment method includes acid etching treatment. The powder raw material is placed in an acid-resistant container, acid solution is added for soaking treatment, and then it is washed with deionized water until neutral and dried.

6. A method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin sheet according to claim 4, characterized in that, The pretreatment includes adding the weighed surfactant to the powder raw material and fully mixing it in a mixing device; the addition amount of the surfactant is 0.5 - 1% of the mass of the powder raw material, so that the surfactant uniformly wraps the surface of the powder raw material.

7. A method for forming a high - thermal - conductivity and conductive aluminum alloy powder - rolled thin plate according to claim 4, characterized in that, The pretreatment includes treatment with a silane coupling agent. The powder raw material is added to the prepared silane coupling agent solution, stirred evenly and then soaked, and dried after taking out.

8. A method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin plate according to claim 4, characterized in that, The surface of the silicon carbide powder is modified, and a metallic aluminum coating is deposited on the surface of the silicon carbide powder by chemical vapor deposition to improve the wettability between the silicon carbide and the aluminum alloy powder and enhance the interfacial bonding strength.

9. A method for forming a high thermal conductivity and conductive aluminum alloy powder rolled thin sheet according to claim 1, characterized in that, It also includes micro-arc oxidation treatment on the surface of the medium plate material to form a ceramic oxide film on its surface, improving the wear resistance, corrosion resistance and surface hardness of the medium plate material.

10. A method for forming a high thermal conductivity and electrically conductive aluminum alloy powder rolled thin sheet according to claim 1, characterized in that, It also includes electroless metal plating treatment on the surface of the medium plate material to form a metal coating on the surface of the medium plate material.