Preparation method of molybdenum wire with copper-plated surface

Abstract

The invention discloses a preparation method of a surface copper-plated molybdenum wire, which innovatively introduces an electrolysis process after a traditional molybdenum wire processing technology, removes a surface graphite coating through electrochemical pretreatment to prepare a clean white wire substrate, and then realizes uniform plating of a copper layer by adopting an electroplating technology. According to the innovative method, the smoothness of the surface of the molybdenum wire is improved through electrolytic cleaning, a better environment is provided for copper plating, the copper plating layer protects the molybdenum wire, meanwhile, the conductivity of the electrode wire is remarkably improved, the overall resistance of the electrode wire is reduced, discharge energy is saved, and loss of the electrode wire in the machining process is reduced; the high conductivity requirement of large-current cutting can be met, and the surface quality requirement of small-current fine machining can also be met.

Description

Technical Field

[0001] The present invention relates to the field of metal processing technology, specifically a method for preparing copper-plated molybdenum wire, particularly suitable for high-current high-speed cutting and low-current precision machining. By optimizing the molybdenum wire surface treatment and electroplating process, this technology significantly improves the conductivity and processing stability of the electrode wire. It is widely applicable to high-precision wire cutting applications such as precision mold manufacturing and aerospace component processing. Background Art

[0002] Molybdenum wire, a key metal material, is widely used in fields such as wire EDM, semiconductor manufacturing, and specialty machining due to its excellent high-temperature strength, electrical conductivity, and low thermal expansion coefficient. In these applications, the electrical conductivity of molybdenum wire, when used as an electrode wire, directly impacts machining efficiency and energy consumption. However, the inherent limited electrical conductivity of pure molybdenum wire limits its potential for high-precision, high-efficiency machining.

[0003] To address this issue, molybdenum-copper alloy molybdenum wire is currently widely used. This material combines molybdenum with copper, aiming to improve its electrical conductivity while maintaining the good mechanical properties of molybdenum. However, due to the significant differences in the physical and chemical properties of molybdenum and copper, the alloy preparation process is prone to structural inhomogeneity, resulting in unstable material properties. Furthermore, the production process of molybdenum-copper alloy is complex, requiring precise control of the raw material ratio and sintering conditions. This not only increases manufacturing costs but also easily causes cracks or delamination during the subsequent drawing process, affecting the yield rate.

[0004] In contrast, copper-plated molybdenum wire offers a more flexible and economical solution. This method involves depositing a copper layer approximately 0.005mm thick on the surface of a white molybdenum wire through an electroplating process. This approach preserves the molybdenum wire's inherent high strength and high-temperature resistance while effectively improving its electrical conductivity and reducing electrical resistance, thereby minimizing energy loss during discharge.

[0005] Copper-coated molybdenum wire is particularly well-suited for wire EDM processes. In practice, it not only achieves high-speed cutting at high currents, but also performs fine machining at low currents, meeting the processing requirements of diverse working conditions. Furthermore, the presence of the copper layer prevents oxidation of the molybdenum wire at high temperatures, extending its service life and reducing maintenance frequency and replacement costs.

[0006] Copper plating technology is relatively mature and highly controllable, allowing for the adjustment of coating thickness and structure to suit specific application requirements. Compared to traditional alloying methods, this approach eliminates the need for complex metallurgical processes, streamlining the production process and reducing manufacturing complexity and costs. More importantly, copper-plated molybdenum wire exhibits a more uniform and stable structure, avoiding potential issues with varying material composition within alloys and resulting in more consistent overall performance.

[0007] As modern manufacturing continues to demand higher performance from materials, copper-coated molybdenum wire is gradually demonstrating its unique advantages. It not only overcomes the poor conductivity of pure molybdenum wire but also overcomes the shortcomings of molybdenum-copper alloys in terms of microstructure uniformity, processability, and cost control. In the future, with the advancement of precision machining technology, copper-coated molybdenum wire is expected to be widely used in more fields, becoming a key choice for high-performance electrode wire materials.

[0008] In summary, copper-coated molybdenum wire is a new material that combines practicality and economy. Through simple surface modification, it optimizes the functionality of molybdenum wire and improves its overall performance, showing promising market prospects and technological promotion value. Summary of the Invention

[0009] The present invention provides a method for preparing a molybdenum wire with a copper coating on its surface. This innovative method solves the problems of insufficient conductivity of existing molybdenum electrode wires, large electrode loss, and poor coating bonding. The method first produces molybdenum wire using traditional process methods, with the diameter of the molybdenum wire retained at or above 0.24 mm, and undergoes electrolytic treatment to remove the graphite coating on the surface of the molybdenum wire. Subsequently, the copper coating is bonded to the molybdenum wire through a copper electroplating process by controlling the current and temperature. The copper-plated molybdenum wire is then processed to a diameter suitable for a wire cutting machine, and finally, the finished copper-plated molybdenum wire is obtained through cleaning and drying. The prepared copper-plated molybdenum wire has excellent electrical conductivity and a strong coating bonding, and is particularly suitable for fine processing of large and small currents.

[0010] The specific technical solutions adopted in the present invention are as follows:

[0011] A method for preparing a surface copper-plated molybdenum wire is characterized in that, after drawing and forming, a molybdenum wire substrate is obtained, and an electrolysis process is added after the traditional molybdenum wire processing and forming process. The surface graphite coating is removed by electrolysis to form a clean white wire substrate, and copper plating is performed on the white wire substrate. The wire is then processed into a molybdenum wire size suitable for a wire cutting machine tool, and cleaned and dried to finally obtain a finished copper-plated molybdenum wire that meets the requirements. This method removes the graphite coating attached to the surface of the molybdenum wire while adding a copper plating layer, thereby improving the conductivity of the electrode wire and reducing the loss of the electrode wire during processing. The method is particularly suitable for fine processing of large and small currents.

[0012] The diameter of the molybdenum wire after drawing is greater than 0.24 mm.

[0013] The electrolysis treatment current is controlled within the range of 10 to 80A, and the voltage is controlled within the range of 10 to 15V.

[0014] The copper plating electroplating solution is mainly composed of a sulfate system, which mainly includes copper sulfate, sulfuric acid and chloride ions.

[0015] The copper plating treatment electroplating temperature is controlled at 20-40°C.

[0016] The current of the copper plating process is controlled at 3 to 8 A / dm 2 .

[0017] The thickness of the copper plating layer is controlled at 0.005 mm.

[0018] The size of the molybdenum wire suitable for the wire cutting machine is controlled at 0.18-0.20 mm.

[0019] Compared with the prior art, the present invention has the following specific beneficial effects:

[0020] The present invention achieves copper plating on the surface of white wire by adopting electrochemical pretreatment and electroplating process, which significantly improves the comprehensive performance of electrode wire. The electrochemical method removes the graphite coating on the surface of molybdenum wire processed by traditional process, provides a better electroplating environment for electroplating process, and significantly improves the bonding strength between the copper plating layer and the surface of molybdenum wire. At the same time, the copper plating layer reduces the resistivity of electrode wire and greatly improves the conductive performance, so that it can meet the requirements of high current efficient cutting and low current precision cutting at the same time. The copper plating layer protects the loss of electrode wire during processing to a certain extent, and increases the service life of electrode wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the structure diagram of molybdenum wire after drawing;

[0022] Figure 2 Schematic diagram of electrolytic pretreatment;

[0023] Figure 3 This is a schematic diagram of the copper electroplating process for white silk;

[0024] Figure 4 This is the structure diagram of copper-plated molybdenum wire. DETAILED DESCRIPTION

[0025] The first step is to calcine ammonium molybdate to reduce it into pure molybdenum powder, and then make it into molybdenum wire substrate through pressing and drawing technology, keeping the diameter of molybdenum wire above 0.24mm, and attaching graphite coating on the surface of molybdenum wire. Figure 1 shown.

[0026] Step 2: Figure 2As shown, the drawn molybdenum wire is sent to the electrolytic cell for electrochemical pretreatment to remove the graphite coating on the surface of the molybdenum wire. The current is controlled at 10-80A and the voltage is controlled at 10-15V. After the processing is completed, the electrolyte on the surface of the molybdenum wire is cleaned and dried.

[0027] Step 3: Figure 3 As shown, the white silk made by electrolytic treatment is sent to the electroplating tank for electroplating treatment. The electroplating solution is mainly a sulfate system, mainly including copper sulfate, sulfuric acid, and chloride ions. The temperature is controlled at 20-40°C and the current is controlled at 3-8A / dm 2 The thickness of the copper plating layer is controlled at 0.005mm. After the processing is completed, the electroplating liquid on the surface of the copper-plated molybdenum wire is cleaned and dried.

[0028] The fourth step is to use the multi-mode drawing process to draw the copper-plated molybdenum wire and control its diameter to 0.18-0.20mm, which is suitable for the use of wire cutting machine tools, such as Figure 4 As shown, the tensile strength and stress of the copper-plated molybdenum wire are tested.

Claims

1. The present invention provides a method for preparing a surface copper-plated molybdenum wire, characterized in that: After the molybdenum wire is drawn and formed, the molybdenum wire with a graphite coating on the surface is fed into an electrolytic cell for electrolytic treatment. After the electrical and non-electrical parameters are controlled to remove the graphite coating on the surface of the molybdenum wire to make a white wire, the white wire substrate is placed in an electroplating solution, and the temperature and current are controlled to perform copper plating. The copper-plated molybdenum wire is then processed to a diameter suitable for the wire cutting machine, and then cleaned and dried.

2. The method for preparing a surface copper-plated molybdenum wire according to claim 1, wherein: The diameter of the molybdenum wire after drawing is greater than 0.24 mm.

3. The method for preparing a surface copper-plated molybdenum wire according to claim 1, wherein: In the electrolysis treatment, the current is controlled at 10-80A and the voltage is controlled at 10-15V.

4. The method for preparing a surface copper-plated molybdenum wire according to claim 1, wherein: The electroplating solution is mainly composed of a sulfate system, mainly including copper sulfate, sulfuric acid and chloride ions.

5. The method for preparing a surface copper-plated molybdenum wire according to claim 1, wherein: The copper plating treatment temperature is controlled at 20-40°C.

6. The method for preparing a surface copper-plated molybdenum wire according to claim 1, characterized in that: The copper plating current is controlled at 3-8A / dm 2 .

7. The method for preparing a surface copper-plated molybdenum wire according to claim 1, characterized in that: The thickness of the copper plating layer should be 0.005mm.

8. The method for preparing a surface copper-plated molybdenum wire according to claim 1, characterized in that: The final diameter of the molybdenum wire is 0.18-0.20 mm, so as to be used in conjunction with a wire cutting machine.

9. The method for preparing a surface copper-plated molybdenum wire according to claim 1, characterized in that: The surface of the molybdenum wire is copper-plated, and the copper-plated layer is evenly covered on the surface of the molybdenum wire substrate and is firmly bonded to the substrate.

10. The method for preparing a surface copper-plated molybdenum wire according to claim 1, characterized in that: The molybdenum wire with copper coating on the surface is suitable for high current cutting and low current fine cutting.

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