A copper additive and its preparation method

Abstract

This invention relates to the field of alloy smelting and discloses a copper additive and its preparation method. The copper additive, by mass percentage, comprises the following raw materials: 90-96% copper powder, 1-3% surfactant, 0.1-3% flux, and the balance being aluminum powder. The particle sizes of the copper and aluminum powders are gradient-mixed. This invention adds flux and surfactant to the additive system. The surfactant reduces the settling speed, while the flux increases the melting speed, ensuring complete melting and efficient function of the additive. Further research into the types, formulations, and amounts of surfactant and flux has led to the optimal solution obtained through practical verification. The additive of this invention has a low melting temperature and high recovery rate. Applying the copper additive prepared by this technical solution to the preparation of aluminum alloys can ensure the corrosion resistance, wear resistance, hardness, and fatigue strength of the aluminum alloys, and can also improve the purity of the alloys.

Description

Technical Field

[0001] This invention relates to the field of alloy smelting, and specifically to a copper additive and its preparation method. Background Technology

[0002] Industrial pure aluminum has a low density and excellent electrical and thermal conductivity, corrosion resistance, and plasticity, making it suitable for processing into plates, strips, foils, and extruded products. However, its mechanical properties are relatively low. Adding alloying elements to aluminum to create aluminum alloys can significantly improve these properties, including tensile strength and hardness. Aluminum alloys are among the most widely used non-ferrous metal structural materials in industry, finding extensive applications in aerospace, automotive, machinery manufacturing, shipbuilding, and chemical industries. With the continuous development of aluminum processing and the aluminum alloy industry, the research and development of aluminum alloys has become a key technology for development.

[0003] Copper is one of the important alloying elements in aluminum alloys, exhibiting solid solution strengthening effects. Furthermore, the CuAl2 precipitated during aging provides significant age-hardening. Copper also improves the mechanical and machinability of aluminum alloys. Copper's melting point is 1083.4℃, 423.4℃ higher than aluminum's 660℃. This necessitates a higher temperature for copper to melt when added to aluminum alloys. High-temperature melting causes the molten aluminum to vaporize, leading to burn-off. Simultaneously, during this process, unvaporized molten aluminum readily reacts with surrounding oxygen, hydrogen, and water at high temperatures, forming impurities that are difficult to remove. This results in low purity aluminum alloys with mechanical properties that fail to meet application requirements. Summary of the Invention

[0004] The present invention aims to provide a copper additive and its preparation method to solve the problem in the prior art that the addition of copper in the preparation of aluminum alloys requires melting at high temperature, resulting in low purity and unsatisfactory mechanical properties of the aluminum alloys.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a copper additive, comprising the following raw materials by mass percentage: 90-96% copper powder, 1-3% surfactant, 0.1-3% flux, with the balance being aluminum powder, wherein the particle sizes of the copper powder and aluminum powder are gradient-mixed.

[0006] Preferably, as an improvement, the particle size gradient range of copper powder and the proportion of copper powder of each particle size are as follows: 120-150 mesh accounts for 8-12%, 150-250 mesh accounts for 15-25%, 250-400 mesh accounts for 25-45%, and the balance is copper powder of >400 mesh.

[0007] Preferably, as an improvement, the particle size gradient range of copper powder and the proportion of copper powder of each particle size are as follows: 10-12% for 120-150 mesh, 15-20% for 150-250 mesh, 30-45% for 250-400 mesh, and the remainder is copper powder of >400 mesh.

[0008] Preferably, as an improvement, the particle size gradient range of aluminum powder and the proportion of aluminum powder of each particle size are as follows: 15-30% for 80-150 mesh, 30-60% for 150-250 mesh, and the remainder is aluminum powder with a particle size greater than 250 mesh.

[0009] Preferably, as an improvement, the particle size gradient range of aluminum powder and the proportion of aluminum powder of each particle size are as follows: 15-20% for 80-150 mesh, 45-60% for 150-250 mesh, and the remainder is aluminum powder with a particle size greater than 250 mesh.

[0010] Preferably, as an improvement, the surfactant is a mixture of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate in a mass ratio of 1:1.

[0011] Preferably, as an improvement, the flux is at least one of potassium fluoroborate, potassium fluorotitanate, potassium fluorosilicate, and potassium fluoroaluminate.

[0012] Preferably, as an improvement, the flux is a mixture of potassium fluoroborate and potassium fluorotitanate in a mass ratio of (1-3):(2-4.5).

[0013] Preferably, as an improvement, a method for preparing a copper additive includes the following steps:

[0014] Step 1: Raw material crushing and sieving: The copper powder and aluminum powder are crushed and sieved. After sieving, the particle sizes of the copper powder and aluminum powder are mixed in a gradient. The particle size gradient range of the copper powder and the proportion of each particle size are as follows: 120-150 mesh accounts for 8-12%, 150-250 mesh accounts for 15-25%, 250-400 mesh accounts for 25-45%, and the remainder is copper powder with a particle size greater than 400 mesh.

[0015] The particle size gradient range of aluminum powder and the proportion of each particle size are as follows: 80-150 mesh accounts for 15-30%, 150-250 mesh accounts for 30-60%, and the remainder is aluminum powder with a particle size greater than 250 mesh.

[0016] Step 2, Ingredients and Mixing: The sieved copper powder and aluminum powder are mixed with surfactants and fluxes to obtain a mixture;

[0017] Step 3: Pressing: Press the mixture into shape to obtain a blank;

[0018] Step 4: Drying: Dry the billet;

[0019] Step 5: Sieving.

[0020] Preferably, as an improvement, in step three, the pressing pressure is 25-28 MPa.

[0021] The principle and advantages of this solution are as follows: In practical applications, addressing the problem of low purity and unsatisfactory mechanical properties in aluminum alloys due to the high-temperature melting required for copper addition during aluminum alloy preparation in existing technologies, the inventors analyzed the causes and found a strong correlation between melting temperature, melting rate, and the particle size of the metal powder. Larger metal powder particle sizes result in lower compactness of the pressed billet, making it easy for the powdered material to detach within the aluminum alloy system, and the melting rate of large-particle detachments is also slower. Conversely, smaller metal powder particle sizes, while resulting in more compact pressing, do not significantly lower the melting temperature. Furthermore, excessive pressing density can cause the billet to sink rapidly to the bottom of the furnace, leading to incomplete melting and sedimentation of the additives, further hindering their melting and dispersion. Moreover, existing metal additives generally use metal powders of a single particle size for pressing, making it difficult to simultaneously address the issues of detachment and sedimentation through particle size control.

[0022] In this technical solution, the inventors, after years of research, have broken through existing technological barriers and creatively adopted a gradient particle size ratio of metal element powders. They conducted separate research and exploration on the particle sizes of copper and aluminum, discovering that a gradient particle size ratio of metal powders, compared to the traditional single particle size ratio, can balance the issues of powder material shedding and melting temperature. Furthermore, there are certain differences in the particle size gradients of copper and aluminum. The optimal particle size gradient range and proportion of copper powder for each particle size are: 120-150 mesh 8-12%, 150-250 mesh 15-25%, 250-400 mesh 25-45%, with the remainder being >400 mesh. For aluminum powder, the optimal particle size gradient range and proportion of aluminum powder for each particle size are: 80-150 mesh 15-30%, 150-250 mesh 30-60%, with the remainder being >250 mesh. Furthermore, in this technical solution, the addition of flux and surfactant reduces the sinking rate under the action of the surfactant and increases the melting rate under the action of the flux, ensuring that the additive completely melts and functions efficiently. The inventors continued to conduct further research on the types, formulations, and amounts of surfactants and fluxes, and finally obtained the optimal solution of this application through practical verification. Applying the copper additive prepared by this technical solution to the preparation of aluminum alloys can ensure the corrosion resistance, wear resistance, hardness, and fatigue strength of the aluminum alloys, and can also improve the purity of the alloys. Detailed Implementation

[0023] The following detailed description provides further details on specific embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; and the materials and reagents used are all commercially available.

[0024] Overview of the plan:

[0025] A copper additive, by weight percentage, comprises the following raw materials: 90-96% copper powder, 1-3% surfactant, 0.1-3% flux, and the balance being aluminum powder.

[0026] The copper and aluminum powders are mixed in a gradient. The particle size gradient range of the copper powder and the proportion of each particle size are as follows: 120-150 mesh accounts for 8-12%, 150-250 mesh accounts for 15-25%, 250-400 mesh accounts for 25-45%, and the remainder is copper powder with a particle size greater than 400 mesh.

[0027] The particle size gradient range of aluminum powder and the proportion of each particle size are as follows: 80-150 mesh accounts for 15-30%, 150-250 mesh accounts for 30-60%, and the remainder is aluminum powder with a particle size greater than 250 mesh.

[0028] The surfactant is at least one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

[0029] The flux is at least one of potassium fluoroborate, potassium fluorotitanate, potassium fluorosilicate, and potassium fluoroaluminate.

[0030] A method for preparing a copper additive includes the following steps:

[0031] Step 1: Raw material crushing and sieving: The copper powder and aluminum powder are crushed and sieved. After sieving, the particle sizes of the copper powder and aluminum powder are mixed in a gradient. The particle size gradient range of the copper powder and the proportion of each particle size are as follows: 120-150 mesh accounts for 8-12%, 150-250 mesh accounts for 15-25%, 250-400 mesh accounts for 25-45%, and the remainder is copper powder with a particle size greater than 400 mesh.

[0032] The particle size gradient range of aluminum powder and the proportion of each particle size are as follows: 80-150 mesh accounts for 15-30%, 150-250 mesh accounts for 30-60%, and the remainder is aluminum powder with a particle size greater than 250 mesh.

[0033] Step 2, Ingredients and Mixing: Mix the sieved copper powder and aluminum powder with surfactant and flux. The mixing time is 30-60 minutes and the mixing speed is 18-20 rpm to obtain the mixture.

[0034] Step 3: Pressing: Press the mixture into shape at a pressure of 25-28 MPa to obtain a billet;

[0035] Step 4: Drying: Dry the billet at a temperature of 100℃;

[0036] Step 5, sieving: sieve through a 10-12mm sieve.

[0037] Examples 1-4 are embodiments of the present invention, and Comparative Examples 1-6 are comparative examples of the present invention. The differences between the embodiments and comparative examples lie in the types of raw materials, the amount added, and the selection of processing parameters. For details, please refer to Table 1 and Table 2.

[0038] Table 1. Summary of Examples

[0039]

[0040]

[0041] Table 2 Comparative Examples

[0042]

[0043]

[0044] Experiment 1: Performance Verification of Copper Additives

[0045] The copper additives prepared in the above embodiments and comparative examples were subjected to performance tests. The test indicators included: additive melting temperature, additive melting time, and additive recovery rate. The additive melting temperature and additive melting time were recorded by conventional observation. The additive recovery rate was calculated as (recovery amount / addition amount) × 100%. The test results are shown in Table 3 below. The results show that when using the copper additives prepared in Examples 1-4 of this technical solution for aluminum alloy smelting, the melting temperature can be significantly reduced, the melting time can be shortened, and the recovery rate can reach over 99%. However, using metal powder with a single particle size cannot achieve the same effect. Furthermore, the selection and addition of flux and surfactant have a significant impact on the additive melting temperature, time, and recovery rate.

[0046] Table 3

[0047]

[0048]

[0049] Application examples

[0050] The copper additives prepared using the above embodiments and comparative examples were used to smelt aluminum alloys, and the properties of the aluminum alloys were tested. The test indicators included corrosion resistance, wear resistance, hardness, and fatigue strength. The results showed that the copper additives prepared using this technical solution can significantly improve the corrosion resistance, wear resistance, hardness, and fatigue strength of aluminum alloys.

[0051] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A copper additive, characterized in that: The raw materials, by mass percentage, include: 90-96% copper powder, 1-3% surfactant, 0.1-3% flux, and the balance being aluminum powder. The particle sizes of the copper and aluminum powders are gradient-mixed. The particle size gradient range and the proportion of each particle size of the copper powder are as follows: 8-12% for 120-150 mesh, 15-25% for 150-250 mesh, 25-45% for 250-400 mesh, and the balance being copper powder with a particle size greater than 400 mesh. The particle size gradient range and the proportion of each particle size of the aluminum powder are as follows: 15-30% for 80-150 mesh, 30-60% for 150-250 mesh, and the balance being aluminum powder with a particle size greater than 250 mesh.

2. The copper additive according to claim 1, characterized in that: The particle size gradient range of the copper powder and the proportion of copper powder of each particle size are as follows: 10-12% for 120-150 mesh, 15-20% for 150-250 mesh, 30-45% for 250-400 mesh, and the remainder is copper powder of >400 mesh.

3. The copper additive according to claim 2, characterized in that: The particle size gradient range of the aluminum powder and the proportion of each particle size are as follows: 80-150 mesh accounts for 15-20%, 150-250 mesh accounts for 45-60%, and the remainder is aluminum powder with a particle size greater than 250 mesh.

4. The copper additive according to claim 3, characterized in that: The surfactant is a mixture of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate in a mass ratio of 1:

1.

5. A copper additive according to claim 4, characterized in that: The flux is at least one of potassium fluoroborate, potassium fluorotitanate, potassium fluorosilicate, and potassium fluoroaluminate.

6. A copper additive according to claim 5, characterized in that: The flux is a mixture of potassium fluoroborate and potassium fluorotitanate in a mass ratio of (1-3):(2-4.5).

7. A method for preparing a copper additive according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Raw material crushing and sieving: The copper powder and aluminum powder are crushed and sieved. After sieving, the particle sizes of the copper powder and aluminum powder are mixed in a gradient. The particle size gradient range of the copper powder and the proportion of each particle size are as follows: 120-150 mesh accounts for 8-12%, 150-250 mesh accounts for 15-25%, 250-400 mesh accounts for 25-45%, and the remainder is copper powder with a particle size greater than 400 mesh. The particle size gradient range of aluminum powder and the proportion of each particle size are as follows: 80-150 mesh accounts for 15-30%, 150-250 mesh accounts for 30-60%, and the remainder is aluminum powder with a particle size greater than 250 mesh. Step 2, Ingredients and Mixing: The sieved copper powder and aluminum powder are mixed with surfactants and fluxes to obtain a mixture; Step 3: Pressing: Press the mixture into shape to obtain a blank; Step 4: Drying: Dry the billet; Step 5: Sieving.

8. The method for preparing a copper additive according to claim 7, characterized in that: In step three, the pressing pressure is 25-28 MPa.

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