Preparation method of graphene copper target material

Abstract

The invention discloses a preparation method of a graphene copper target material, which comprises the following steps: step 1, proportioning and mixing: weighing copper powder and graphene powder corresponding to alloy components in percentage by mass, the mass ratio of the graphene powder is 0.1-5%, and uniformly mixing the raw material powder through a mixer; step 2, pre-pressing and forming: putting the uniformly mixed powder raw materials into a cold isostatic pressing mold, pre-pressing and forming the mixture at normal temperature, and operating according to the process that the pressure is 60-180MPa and the pressure holding time is 5-30 minutes; and thirdly, vacuum melting is conducted, specifically, melting of the graphene copper is conducted in a vacuum induction furnace, the pre-pressed mixed powder block materials are fully melted under the condition of 120-160 KW and at the temperature of 1100-1300 DEG C to prepare liquid melt, and argon gas with the pressure of 2-4 Kpa is filled before casting. The graphene copper with high conductivity and high hardness is low in preparation cost, simple in method process and low in equipment requirement, and has a very good industrial application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of target material preparation, and in particular to a method for preparing a graphene copper target material. Background Art

[0002] Copper is a common metal material with excellent electrical and thermal conductivity and good plasticity. In addition, copper has good corrosion resistance and plasticity, and is easy to process into various forms of materials. It is one of the most widely used materials in modern industrial fields such as the modern electronic information industry and the power transmission industry. With the rapid development of aerospace, power transmission, 5G+ communications, new energy vehicles, and unmanned driving, people's demand for high information transmission rate and low power consumption applications is becoming more urgent. At the same time, as a heavy material in the target industry, copper targets are widely used in solar cells, screen displays, and semiconductor chips as conductive materials. With the development of the market and the improvement of the industry level in recent years, higher requirements have been put forward for the performance of copper targets with high electrical and thermal conductivity.

[0003] Existing pure copper targets are limited by the material itself in terms of electrical conductivity, thermal conductivity, oxidation resistance, corrosion resistance, strength and other aspects, and cannot meet the higher requirements of the growing solar cells, screen displays and semiconductor chips. At this time, graphene copper targets are gradually gaining attention and development.

[0004] Graphene copper target fully utilizes the intrinsic properties of graphene such as high conductivity, high strength, and high thermal stability, and combines its advantages of high carrier mobility with the advantages of high carrier concentration of copper. At present, the preparation methods of graphene copper mainly include high-energy ball milling, chemical vapor deposition, electrolytic co-deposition, powder metallurgy, vacuum continuous casting, etc.

[0005] However, the high-intensity mechanical stirring of the traditional high-energy ball milling method will destroy the graphene structure, the powder metallurgy method cannot solve the problem of uniform dispersion of graphene, the electrolytic co-deposition method is easily affected by the current density and the uniformity of solute dispersion, and the bonding force between graphene and the copper layer is poor. At the same time, the chemical vapor phase method is also difficult to obtain high-quality graphene on the copper substrate, resulting in the inability to effectively improve the conductive performance. The vacuum continuous casting method obtains columnar crystals, which cannot meet the requirements of the target material grain size.

[0006] Patent CN113106401A A graphene copper target and its preparation method proposes a graphene copper target, including a target assembly, the target assembly includes an outer copper backing plate and a graphene copper target body, the outer copper backing plate has a groove inside, and the outer wall of the graphene copper target body is provided with a graphene coating. In the graphene copper target manufactured in this way, the graphene and copper materials cannot be fully and evenly dispersed and combined, and the uniformity problem of the two materials cannot be solved. Summary of the invention

[0007] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0008] In view of the problems existing in the above-mentioned existing methods for preparing graphene copper targets, the present invention is proposed.

[0009] Therefore, the object of the present invention is to provide a method for preparing a graphene copper target material, which has high conductivity and high hardness, low preparation cost, simple process, low equipment requirements, and good industrial application prospects.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for preparing a graphene copper target, comprising the following steps:

[0011] Step 1: Proportioning and mixing: Weigh the copper powder and graphene powder corresponding to the alloy components according to the mass percentage, the mass ratio of the graphene powder is 0.1-5%, and mix the raw material powders evenly through a mixer;

[0012] Step 2: Pre-pressing: Place the uniformly mixed powder raw materials in a cold isostatic pressing mold, and pre-press the mixture at room temperature, with a pressure of 60 to 180 MPa and a holding time of 5 to 30 minutes;

[0013] Step 3: Vacuum melting: The melting of graphene copper is carried out in a vacuum induction furnace. The pre-pressed mixed powder block is fully melted at 1100-1300°C under 120-160KW conditions to prepare a liquid melt. Before casting, argon gas 2-4Kpa is filled in and cast into an ingot in a graphite crucible under an argon protection environment;

[0014] Step 4: Forging: The graphene copper ingot needs to be hot forged at 700-900℃, the start forging temperature ≥800℃, and the final forging temperature ≥650℃;

[0015] Step 5: Hot rolling: After heating to 700-900℃, hot rolling is carried out. The rolling is carried out in a one-fire multi-pass manner. The starting rolling temperature is ≥780℃, the final rolling temperature is ≥550℃, the rolling deformation of each pass is 15-20%, and the total deformation is controlled at 60-80%. Water cooling is carried out immediately after rolling is completed;

[0016] Step 6: Annealing: The annealing temperature to eliminate internal stress is controlled at 600-800°C and the annealing time is 1-3h;

[0017] Step 7: Machining: Finally, the graphene copper target of the required size is obtained through machining and milling.

[0018] As a preferred solution of the method for preparing the graphene copper target material of the present invention, the step 2 effectively prevents the floating of the graphene component in the next smelting process, thereby causing the inhomogeneity of the graphene in the material and the change of the component ratio.

[0019] As a preferred scheme of the preparation method of the graphene copper target material described in the present invention, wherein: in the step 4, the forging is light at first and then heavy, light and fast, the forging is rotated frequently, and the operation should be careful when approaching the size, the surface is flat and the size is uniform, and when the temperature is lower than the final forging temperature requirement, it should be returned to the furnace for heating.

[0020] As a preferred scheme of the preparation method of the graphene copper target material of the present invention, as the content of graphene powder added increases from 0% to 5%, the conductivity of the graphene copper target material increases from 75% IACS to 98% IACS and then gradually decreases to 95% IACS. When the graphene ratio in the material ratio is 2%, the conductivity of the graphene copper target material reaches the best.

[0021] As a preferred solution of the method for preparing the graphene copper target material of the present invention, when adding graphene, the grain size of the material is reduced from 45-48 microns of pure copper to 15-23 microns.

[0022] As a preferred solution of the method for preparing the graphene copper target material of the present invention, wherein: the step 2 adopts cold isostatic pressing for pre-pressing, which is beneficial to avoid the two powders from being fully fused to form heterogeneous parts during the smelting process, and avoids the situation where the graphene floats on the surface of the solution due to the reduction in density, thereby obtaining a graphene target material with better performance.

[0023] As a preferred scheme of the preparation method of the graphene copper target material described in the present invention, the water cooling after hot rolling in the step 5 can effectively refine the grains and prevent the grains from growing, and the finer grains have better conductivity and better hardness, confirming that grain refinement strengthening is a mechanism for improving the strength of metals by refining their grains. At the same time, by refining the grains, the number of grain boundaries is reduced, thereby reducing the obstacles to the movement of electrons and improving the conductivity of the material.

[0024] The beneficial effects of the present invention are as follows: the graphene copper target material of the present invention, compared with the ordinary copper target material, introduces graphene. Due to the superior intrinsic properties of graphene such as high conductivity, high strength, and high thermal stability, the advantage of high carrier mobility of graphene is combined with the advantage of high carrier concentration of copper, so that the graphene copper has high conductivity and high hardness compared with the pure copper target material, has low preparation cost, simple method and process, low equipment requirements, and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0026] Figure 1 The figure is a schematic diagram of the overall structure of the method for preparing the graphene copper target material of the present invention;

[0027] Figure 2 This is a metallographic schematic diagram of Example 2 of the method for preparing a graphene copper target material of the present invention;

[0028] Figure 3 This is a metallographic schematic diagram of Example 4 of the method for preparing a graphene copper target of the present invention. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0032] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0033] Reference Figure 1 , provides a method for preparing a graphene copper target, comprising the following steps:

[0034] Step 1: Proportioning and mixing: Weigh the copper powder and graphene powder corresponding to the alloy components according to the mass percentage, the mass ratio of the graphene powder is 0.1-5%, and mix the raw material powders evenly through a mixer;

[0035] Step 2: Pre-pressing: Place the uniformly mixed powder raw materials in a cold isostatic pressing mold, and pre-press the mixture at room temperature, with a pressure of 60 to 180 MPa and a holding time of 5 to 30 minutes;

[0036] Step 3: Vacuum melting: The melting of graphene copper is carried out in a vacuum induction furnace. The pre-pressed mixed powder block is fully melted at 1100-1300°C under 120-160KW conditions to prepare a liquid melt. Before casting, argon gas 2-4Kpa is filled in and cast into an ingot in a graphite crucible under an argon protection environment;

[0037] Step 4: Forging: The graphene copper ingot needs to be hot forged at 700-900℃, the start forging temperature ≥800℃, and the final forging temperature ≥650℃;

[0038] Step 5: Hot rolling: After heating to 700-900℃, hot rolling is carried out. The rolling is carried out in a one-fire multi-pass manner. The starting rolling temperature is ≥780℃, the final rolling temperature is ≥550℃, the rolling deformation of each pass is 15-20%, and the total deformation is controlled at 60-80%. Water cooling is carried out immediately after rolling is completed;

[0039] Step 6: Annealing: The annealing temperature to eliminate internal stress is controlled at 600-800°C and the annealing time is 1-3h;

[0040] Step 7: Machining: Finally, the graphene copper target of the required size is obtained through machining and milling.

[0041] Among them, step 2 effectively prevents the floating of graphene components during the next smelting process, thereby causing the inhomogeneity of graphene in the material and the change of the composition ratio.

[0042] Among them, in step 4, the forgings are light at first and then heavy, light and fast, and the forgings are rotated frequently. When they are close to the size, they should be operated carefully to ensure a smooth surface and uniform size. When the temperature is lower than the final forging temperature requirement, they should be returned to the furnace for heating.

[0043] Furthermore, as the content of graphene powder added increased from 0% to 5%, the conductivity of the graphene copper target increased from 75% IACS to 98% IACS and then gradually decreased to 95% IACS. When the graphene ratio in the material ratio was 2%, the conductivity of the graphene copper target reached the best.

[0044] Among them, step 2 uses cold isostatic pressing for pre-pressing, which is beneficial to avoid the two powders from being fully fused to form heterogeneous parts during the smelting process, and avoids the situation where graphene floats on the surface of the solution due to reduced density, thereby obtaining a graphene target with better performance.

[0045] Furthermore, water cooling after hot rolling in step five can effectively refine the grains and prevent grain growth, and finer grains have better conductivity and better hardness, confirming that grain refinement strengthening is a mechanism that improves the strength of metals by refining their grains. At the same time, by refining the grains, the number of grain boundaries is reduced, thereby reducing the obstacles to electron movement and improving the conductivity of the material.

[0046] Compared with ordinary copper target materials, the graphene copper target material of the present invention introduces graphene. Due to the superior intrinsic properties of graphene such as high electrical conductivity, high strength and high thermal stability, the advantage of high carrier mobility of graphene is combined with the advantage of high carrier concentration of copper, so that compared with pure copper target materials, the graphene copper has high electrical conductivity and high hardness, low preparation cost, simple method and process, low equipment requirements, and good industrial application prospects.

[0047] With reference to the following table, specific embodiments are shown in Table 1:

[0048] Table 1 Different graphene ratios in graphene copper target

[0049]

[0050]

[0051] From Example 1 to Example 9, it can be seen that as the content of graphene addition increases from 0% to 5%, the conductivity of the graphene copper target increases from 75% IACS to 98% IACS and then gradually decreases to 95% IACS. When the graphene ratio in the material ratio is 2%, the conductivity of the graphene copper target reaches the best. At the same time, it can be seen that when graphene is added, the grain size of the material is reduced from 45-48 microns of pure copper to 15-23 microns (refer to the metallographic diagram). This is because the introduction of graphene can be used as a heterogeneous part of the copper powder, and the introduction during smelting can effectively promote the nucleation and crystallization of the copper material and play a role in refining the grains. However, when the graphene content is above 2%, up to 5%, it is not possible to form a graphene copper column well during smelting, resulting in the final target conductivity not rising but falling.

[0052] The difference between Comparative Example 1 and Example 8 is that in Example 8, cold isostatic pressing is used for pre-pressing, while in Comparative Example 1, this step is not performed, and graphene powder and copper powder are directly mixed and then smelted. This shows that pre-pressing before smelting is beneficial to avoid the two powders from being fully fused to form heterogeneous parts during the smelting process, and avoids the situation where graphene floats on the surface of the solution due to reduced density, thereby obtaining a graphene target with better performance.

[0053] The difference between Comparative Example 2 and Example 8 is that natural cooling is used at the end of the hot rolling process in Comparative Example 2, and no water cooling is performed. By comparison, it is found that water cooling after hot rolling can effectively refine the grains and prevent the grains from growing, and finer grains have better electrical conductivity and better hardness, confirming that grain refinement strengthening is a mechanism that improves the strength of metals by refining their grains. At the same time, by refining the grains, the number of grain boundaries can be reduced, thereby reducing the obstacles to the movement of electrons and improving the conductivity of the material.

[0054] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for preparing a graphene copper target, characterized in that: The following steps are involved: Step 1: Proportioning and mixing: Weigh the copper powder and graphene powder corresponding to the alloy components according to the mass percentage, the mass ratio of the graphene powder is 0.1-5%, and mix the raw material powders evenly through a mixer; Step 2: Pre-pressing: Place the uniformly mixed powder raw materials in a cold isostatic pressing mold, and pre-press the mixture at room temperature, with a pressure of 60 to 180 MPa and a holding time of 5 to 30 minutes; Step 3: Vacuum melting: The melting of graphene copper is carried out in a vacuum induction furnace. The pre-pressed mixed powder block is fully melted at 1100-1300°C under 120-160KW conditions to prepare a liquid melt. Before casting, argon gas 2-4Kpa is filled in and cast into an ingot in a graphite crucible under an argon protection environment; Step 4: Forging: The graphene copper ingot needs to be hot forged at 700-900℃, the start forging temperature ≥800℃, and the final forging temperature ≥650℃; Step 5: Hot rolling: After heating to 700-900℃, hot rolling is carried out. The rolling is carried out in a one-fire multi-pass manner. The starting rolling temperature is ≥780℃, the final rolling temperature is ≥550℃, the rolling deformation of each pass is 15-20%, and the total deformation is controlled at 60-80%. Water cooling is carried out immediately after rolling is completed; Step 6: Annealing: The annealing temperature to eliminate internal stress is controlled at 600-800°C and the annealing time is 1-3h; Step 7: Machining: Finally, the graphene copper target of the required size is obtained through machining and milling.

2. The method for preparing a graphene copper target according to claim 1, characterized in that: The step 2 effectively prevents the graphene component from floating during the next smelting process, thereby preventing the graphene inhomogeneity and component ratio changes in the material.

3. The method for preparing a graphene copper target according to claim 1, characterized in that: In the step 4, the forging is light at first and then heavy, lightly and quickly, and the forging is rotated frequently. When it is close to the size, it should be operated carefully to ensure a flat surface and uniform size. When the temperature is lower than the final forging temperature requirement, it should be returned to the furnace for heating.

4. The method for preparing a graphene copper target according to claim 1, characterized in that: As the content of graphene powder added increases from 0% to 5%, the conductivity of the graphene copper target increases from 75% IACS to 98% IACS and then gradually decreases to 95% IACS. When the graphene ratio in the material ratio is 2%, the conductivity of the graphene copper target reaches the best.

5. The method for preparing a graphene copper target according to claim 4, characterized in that: When graphene is added, the grain size of the material is reduced from 45-48 microns of pure copper to 15-23 microns.

6. The method for preparing a graphene copper target according to claim 1, characterized in that: The step 2 uses cold isostatic pressing for pre-pressing, which is beneficial to avoid the two powders from being fully fused to form heterogeneous parts during the smelting process, and avoids the situation where the graphene floats on the surface of the solution due to reduced density, thereby obtaining a graphene target with better performance.

7. The method for preparing a graphene copper target according to claim 5, characterized in that: The water cooling after hot rolling in step 5 can effectively refine the grains and prevent grain growth, and finer grains have better conductivity and better hardness, confirming that grain refinement strengthening is a mechanism that improves the strength of metals by refining their grains. At the same time, by refining the grains, the number of grain boundaries is reduced, thereby reducing the obstacles to electron movement and improving the conductivity of the material.

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