Copper-silver alloy with low oxygen content and preparation method and application thereof

Abstract

The invention discloses a copper-silver alloy with low oxygen content and a preparation method and application thereof, and relates to the technical field of alloy wires. Comprising the steps that raw material copper and raw material silver are subjected to vacuum melting, and melt is stirred in the vacuum melting process; and after the vacuum melting is finished, carrying out directional solidification continuous casting on the melt in an inert atmosphere. Metal oxidation can be avoided in the vacuum melting process, oxygen in a melt can be discharged in time by stirring the melt in the melting process, directional solidification continuous casting is matched in the inert atmosphere, the oxygen content in the obtained copper-silver alloy is reduced, the cleanliness of the copper-silver alloy is increased, and the phenomenon of wire breakage during drawing is avoided. In addition, stirring in the smelting process is beneficial to improving the uniformity of alloy components, so that the consistency and stability of the structure performance of the alloy are improved, and the high-performance copper-silver alloy is obtained. In the directional solidification continuous casting process, transverse grain boundaries in the copper-silver alloy are reduced, and the forming machining performance of the copper-silver alloy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy wires, and in particular to a copper-silver alloy with a low oxygen content and a preparation method and application thereof. Background Art

[0002] High-strength and high-conductivity copper-silver alloy ultrafine wire is a special functional material with excellent electrical and thermal conductivity, high strength, good processing performance and strong oxidation resistance. As a connecting line and signal transmission medium, it is widely used in tank chain cables, electronic information integrated circuits, high-end CNC machine tools and robots, aerospace, high-tech ships, rail transit, new energy vehicles and power equipment.

[0003] High-strength and high-conductivity copper-silver alloy ultrafine wires are made by drawing copper-silver alloy wire billets. However, the smaller the diameter of the high-strength and high-conductivity copper-silver alloy ultrafine wires, the more likely they are to break during the drawing process. In order to ensure that no wire breaks occur during the drawing process, higher requirements are placed on the quality of the copper-silver alloy wire billets. However, the copper-silver alloy wire billets with better quality cannot be fully domestically produced at present, and mainly rely on foreign imports. Not only are they expensive, but they also seriously restrict the development of my country's high-end manufacturing industry.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a copper-silver alloy with low oxygen content and a preparation method and application thereof.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a method for preparing a copper-silver alloy with a low oxygen content, comprising vacuum melting raw copper and raw silver, wherein the vacuum melting process comprises stirring the melt; after the vacuum melting is completed, directionally solidifying and continuously casting the melt in an inert atmosphere.

[0008] In an optional embodiment, the stirring time is 5 to 20 minutes.

[0009] In an optional embodiment, the vacuum degree of vacuum melting is 0.001-0.01Pa.

[0010] In an optional embodiment, the melting temperature of the vacuum melting is 1150-1250°C.

[0011] In an alternative embodiment, the inert atmosphere includes any one of an argon atmosphere, a nitrogen atmosphere, or a helium atmosphere.

[0012] In an optional embodiment, the continuous casting speed of the directional solidification continuous casting is 5 to 20 cm / min.

[0013] In an optional embodiment, the cooling method of directional solidification continuous casting is water cooling, the water inlet temperature is 20-30° C., and the water flow rate is 1-5 LPM.

[0014] In an optional embodiment, the raw copper includes electrolytic copper or pure copper, and the raw silver is pure silver.

[0015] In a second aspect, the present invention provides a copper-silver alloy with a low oxygen content, which is prepared by the preparation method of any one of the aforementioned embodiments.

[0016] Preferably, the copper-silver alloy is a copper-silver alloy wire blank with a diameter of 6 to 8 mm.

[0017] In a third aspect, the present invention provides a use of a copper-silver alloy as described in the aforementioned embodiment in the preparation of a high-strength and high-conductivity copper-silver alloy ultrafine wire, wherein the diameter of the high-strength and high-conductivity copper-silver alloy ultrafine wire is less than 30 μm.

[0018] The present invention has the following beneficial effects:

[0019] The present invention provides a copper-silver alloy with low oxygen content and a preparation method and application thereof. By vacuum melting raw copper and raw silver, metal oxidation can be avoided. The melt is stirred during the melting process to discharge oxygen in the melt in time. The directional solidification and continuous casting process is also carried out under an inert atmosphere, so that the oxygen content in the final copper-silver alloy is reduced, the cleanliness of the copper-silver alloy is increased, and the phenomenon of wire breakage during drawing is avoided. In addition, stirring during the melting process is conducive to improving the uniformity of the alloy composition, thereby improving the consistency and stability of the alloy structure performance, and obtaining a high-performance copper-silver alloy; the directional solidification and continuous casting process is conducive to reducing the transverse grain boundaries in the copper-silver alloy and improving the forming and processing performance of the copper-silver alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a picture of the copper-silver alloy ultrafine wire obtained by drawing the copper-silver alloy with low oxygen content provided in Example 3 of the present invention;

[0022] Figure 2 This is a scanning electron microscope image of the copper-silver alloy ultrafine wire obtained by drawing the copper-silver alloy provided in Comparative Example 1 of the present invention;

[0023] Figure 3This is a scanning electron microscope image of the copper-silver alloy ultrafine wire obtained by drawing the copper-silver alloy provided in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0025] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0026] High-strength and high-conductivity copper-silver alloy ultrafine wire has the advantages of excellent electrical and thermal conductivity, high strength, good processing performance and strong oxidation resistance, so it is widely used in many fields and has high demand for use. However, the high-strength and high-conductivity copper-silver alloy ultrafine wire is prepared by drawing a copper-silver alloy wire billet. The smaller the diameter of the high-strength and high-conductivity copper-silver alloy ultrafine wire, the easier it is to break the wire during the drawing process. In order to meet the use demand of the high-strength and high-conductivity copper-silver alloy ultrafine wire, it is urgent to provide a copper-silver alloy suitable for the production of high-strength and high-conductivity copper-silver alloy ultrafine wire. Therefore, the inventor proposes the following solution.

[0027] In a first aspect, the present invention provides a method for preparing a copper-silver alloy with a low oxygen content, comprising vacuum melting raw copper and raw silver, wherein the vacuum melting process comprises stirring the melt; after the vacuum melting is completed, directionally solidifying and continuously casting the melt in an inert atmosphere.

[0028] After long-term research, the inventors found that the oxygen content in the alloy is the key reason for the wire breakage during drawing. The higher the oxygen content, the more oxide inclusions in the copper-silver alloy, which makes it easy for the wire to break during drawing. Therefore, improving the purity of the copper-silver alloy is crucial for drawing the copper-silver alloy to obtain high-strength and high-conductivity copper-silver alloy ultrafine wires.

[0029] Based on this, the inventor proposed vacuum melting, and stirred the melt during the melting process, which can not only avoid metal oxidation, but also discharge oxygen in the melt in time. The directional solidification and continuous casting process is also carried out under an inert atmosphere, so that the oxygen content in the final copper-silver alloy is reduced, the cleanliness of the copper-silver alloy is increased, and the phenomenon of wire breakage during drawing is avoided. In addition, stirring during the melting process is conducive to improving the uniformity of the alloy composition, thereby improving the consistency and stability of the alloy structure and performance, and obtaining a high-performance copper-silver alloy; the directional solidification and continuous casting process is conducive to reducing the transverse grain boundaries in the copper-silver alloy and improving the forming and processing performance of the copper-silver alloy.

[0030] In an optional embodiment, the stirring time is 5 to 20 minutes. For example, the stirring time can be any value among 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, or a range value consisting of any two values, and other point values ​​within the range value.

[0031] The preparation method provided by the present invention can timely discharge oxygen in the melt by controlling the stirring time within the above range, promote the mixing uniformity of copper and silver, and thus improve the consistency and stability of the alloy structure performance.

[0032] In an optional embodiment, the vacuum degree of vacuum melting is 0.001-0.01 Pa. For example, the vacuum degree can be any value among 0.001 Pa, 0.002 Pa, 0.003 Pa, 0.004 Pa, 0.005 Pa, 0.006 Pa, 0.007 Pa, 0.008 Pa, 0.009 Pa and 0.01 Pa, or a range value consisting of any two values ​​and other point values ​​within the range value. By reducing the vacuum degree of the melting process, the purity of the copper-silver alloy can be improved.

[0033] In an optional embodiment, the melting temperature of vacuum melting is 1150-1250° C. For example, the melting temperature can be any value of 1150° C., 1160° C., 1170° C., 1180° C., 1190° C., 1200° C., 1210° C., 1220° C., 1230° C., 1240° C. or 1250° C., or a range value consisting of any two values, and other point values ​​within the range value.

[0034] In an alternative embodiment, the inert atmosphere includes any one of an argon atmosphere, a nitrogen atmosphere, or a helium atmosphere.

[0035] In an optional embodiment, the continuous casting speed of the directional solidification continuous casting is 5 to 20 cm / min. For example, the melting temperature can be any value of 5 cm / min, 6 cm / min, 7 cm / min, 8 cm / min, 9 cm / min, 10 cm / min, 11 cm / min, 12 cm / min, 13 cm / min, 14 cm / min, 15 cm / min, 16 cm / min, 17 cm / min, 18 cm / min, 19 cm / min or 20 cm / min, or a range value consisting of any two values, and other point values ​​within the range value.

[0036] In an optional embodiment, the cooling method of directional solidification continuous casting is water cooling, the water inlet temperature is 20-30° C., and the water flow rate is 1-5 LPM.

[0037] For example, the inlet water temperature can be any value among 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C, or a range value consisting of any two values ​​and other point values ​​within the range value.

[0038] For example, the water flow rate can be any value among 1LPM, 2LPM, 3LPM, 4LPM or 5LPM, or a range value consisting of any two values ​​and other point values ​​within the range value.

[0039] In an optional embodiment, the raw copper includes electrolytic copper or pure copper, and the raw silver is pure silver.

[0040] In a second aspect, the present invention provides a copper-silver alloy with a low oxygen content, which is prepared by the preparation method of any one of the aforementioned embodiments.

[0041] Preferably, the copper-silver alloy is a copper-silver alloy wire billet with a diameter of 6 to 8 mm. It can be understood that the wire billet refers to the copper-silver alloy in a linear billet state, and the billet is a product obtained by a continuous casting process.

[0042] In a third aspect, the present invention provides a use of a copper-silver alloy as described in the aforementioned embodiment in the preparation of a high-strength and high-conductivity copper-silver alloy ultrafine wire, wherein the diameter of the high-strength and high-conductivity copper-silver alloy ultrafine wire is less than 30 μm.

[0043] Example 1

[0044] This embodiment provides a copper-silver alloy Cu2Ag with low oxygen content, and the preparation method thereof is as follows:

[0045] Electrolytic copper and pure silver were used as raw materials, and vacuum melting was carried out at a temperature of 1150°C under a vacuum degree of 0.01Pa. The melt was stirred during the vacuum melting process for 20 minutes. After the melting was completed, the melt was directionally solidified and continuously cast into a copper-silver alloy wire billet in an argon atmosphere, with a continuous casting speed of 20cm / min, a water inlet temperature of 30°C, and a water flow rate of 1LPM.

[0046] The diameter of the copper-silver alloy wire blank prepared in this embodiment is 6 mm, and the oxygen content is 5 ppm.

[0047] Example 2

[0048] This embodiment provides a copper-silver alloy Cu2Ag with low oxygen content, and the preparation method thereof is as follows:

[0049] Electrolytic copper and pure silver were used as raw materials, and vacuum melting was carried out at a temperature of 1200°C under a vacuum degree of 0.01Pa. The melt was stirred during the vacuum melting process for 10 minutes. After the melting was completed, the melt was directionally solidified and continuously cast into a copper-silver alloy wire billet in an argon atmosphere, with a continuous casting speed of 10cm / min, a water inlet temperature of 25°C, and a water flow rate of 3LPM.

[0050] The diameter of the copper-silver alloy wire blank prepared in this embodiment is 7 mm, and the oxygen content is 4 ppm.

[0051] Example 3

[0052] This embodiment provides a copper-silver alloy Cu2Ag with low oxygen content, and the preparation method thereof is as follows:

[0053] Electrolytic copper and pure silver were used as raw materials, and vacuum melting was carried out at a temperature of 1250°C under a vacuum degree of 0.001Pa. The melt was stirred during the vacuum melting process for 5 minutes. After the melting was completed, the melt was directionally solidified and continuously cast into a copper-silver alloy wire billet in an argon atmosphere, with a continuous casting speed of 5cm / min, a water inlet temperature of 20°C, and a water flow rate of 5LPM.

[0054] The diameter of the copper-silver alloy wire blank prepared in this embodiment is 8 mm, and the oxygen content is 3 ppm.

[0055] Comparative Example 1

[0056] This comparative example provides a copper-silver alloy Cu2Ag, and its preparation method is as follows:

[0057] S01. Raw material batching: weigh a certain mass of high-purity cathode electrolytic copper and high-purity silver, the purity of which is above 99.99%.

[0058] S02, preparing copper-silver alloy slurry, placing the high-purity cathode electrolytic copper and high-purity silver weighed in step a in a graphite crucible, and performing vacuum induction melting to obtain copper-silver alloy slurry, wherein the melting vacuum degree is 1×10 2 Pa, the melting temperature is 1150℃, the protective atmosphere is high-purity argon, and the melting time is 30min.

[0059] S03. Prepare a copper-silver alloy rod. The silver-copper alloy slurry melted in step b is continuously casted under a high-purity argon atmosphere to prepare a copper-silver alloy rod. The downward speed is 1.5 mm / s, the pause time is 0.8 s, the cooling method is water cooling, the diameter of the copper-silver alloy rod is 8 mm, and the oxygen content is 12 ppm.

[0060] Comparative Example 2

[0061] This comparative example provides a copper-silver alloy Cu2Ag, which is the same as Example 3, except that no protective gas is added during the preparation method.

[0062] The diameter of the copper-silver alloy wire blank prepared in this comparative example is 8 mm, and the oxygen content is 15 ppm.

[0063] Comparative Example 3

[0064] This comparative example provides a copper-silver alloy Cu2Ag, which is the same as Example 3, except that in the preparation method, vacuum melting is performed at a temperature of 1100°C.

[0065] The diameter of the copper-silver alloy wire blank prepared in this comparative example is 8 mm, surface cracks appear on the copper-silver alloy wire blank, and the oxygen content is 16 ppm.

[0066] Comparative Example 4

[0067] This comparative example provides a copper-silver alloy Cu2Ag, which is the same as Example 3, except that in the preparation method, vacuum melting is performed at a temperature of 1300°C.

[0068] The diameter of the copper-silver alloy wire billet prepared in this comparative example is 8 mm. Due to the high melting temperature, continuous casting leakage occurs and continuous casting cannot be carried out continuously and stably.

[0069] Test Example 1

[0070] The copper-silver alloy wire billets provided in Examples 1 to 3 and Comparative Examples 1 to 4 were prepared into high-strength and high-conductivity copper-silver alloy ultrafine wires Cu2Ag, and the drawing conditions of the copper-silver alloy wire billets during the preparation process and the diameters of the prepared high-strength and high-conductivity copper-silver alloy ultrafine wires were observed, and the diameters of the obtained high-strength and high-conductivity copper-silver alloy ultrafine wires were obtained as shown in Tables 1 and Figure 1 to Figure 3 shown.

[0071] The copper-silver alloy wire blanks provided in Examples 1 to 3 and Comparative Examples 1 to 4 have the same mass ratio of copper to silver. The method for preparing the high-strength and high-conductivity copper-silver alloy ultrafine wire is as follows:

[0072] The diameter of the copper-silver alloy wire billet is 8 mm. Wires of different thicknesses are obtained through large drawing, medium drawing and fine drawing, and the intermediate annealing temperature is 480°C.

[0073] Table 1 Drawing conditions of copper-silver alloy wire blanks provided in the embodiments and comparative examples

[0074] Ultrafine wire diameter / μm Remark Example 1 25 The wire surface is smooth and has no defects Example 2 20 The wire surface is smooth and has no defects Example 3 18 The wire surface is smooth and has no defects Comparative Example 1 40 The wire surface is smooth and the wire breakage is less than 40μm when drawn. Comparative Example 2 56 The wire surface is smooth and wire breakage occurs during drawing Comparative Example 3 - The copper-silver alloy wire billet has cracks on its surface and cannot be drawn Comparative Example 4 - Copper-silver alloy wire billet continuous casting leakage, can not be drawn

[0075] From Table 1 and Figure 1 to Figure 3It can be seen that the copper-silver alloy wire billet prepared in the embodiment of the present invention has a low oxygen content, so the high-strength and high-conductivity copper-silver alloy ultrafine wire obtained by drawing has good surface quality, and there is no wire breakage during the drawing process, which provides an excellent basis for meeting the use requirements of high-strength and high-conductivity copper-silver alloy ultrafine wires. However, since there is no stirring in Comparative Example 1, degassing and component homogenization are not achieved, resulting in the inability to draw wires with a diameter of less than 30μm. The surface of the wire in Comparative Example 2 is smooth, but the wire breaks when drawn to 56μm. The surface of the copper-silver alloy wire billet in Comparative Example 3 has cracks and cannot be drawn. The copper-silver alloy wire billet in Comparative Example 4 has leakage during continuous casting and cannot be drawn.

[0076] The present invention provides a copper-silver alloy with low oxygen content, a preparation method and application thereof. By controlling the oxygen content in the environment at each stage of the preparation and cooperating with a stirring process during vacuum melting, the oxygen content in the copper-silver alloy can be greatly reduced. Compared with the existing copper-silver alloy (i.e., the copper-silver alloy that is directly continuously cast and not stirred during the melting process), the oxygen content is reduced by more than 50%, the cleanliness of the copper-silver alloy is improved, and the phenomenon of wire breakage during drawing is avoided. The alloy is suitable for preparing high-strength and high-conductivity copper-silver alloy ultrafine wires with a diameter of less than 30 μm.

[0077] In addition, stirring during the smelting process is beneficial to improving the uniformity of the alloy composition, thereby improving the consistency and stability of the alloy's microstructure and properties, and obtaining a high-performance copper-silver alloy; the directional solidification continuous casting process is beneficial to reducing the transverse grain boundaries in the copper-silver alloy and improving the forming and processing properties of the copper-silver alloy.

[0078] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a copper-silver alloy with low oxygen content, characterized in that: The method comprises vacuum melting raw copper and raw silver, wherein the melt is stirred during the vacuum melting; after the vacuum melting is completed, the melt is directionally solidified and continuously cast in an inert atmosphere.

2. The preparation method according to claim 1, characterized in that: The stirring time is 5 to 20 minutes.

3. The preparation method according to claim 1, characterized in that: The vacuum degree of the vacuum melting is 0.001-0.01Pa.

4. The preparation method according to claim 1, characterized in that: The melting temperature of the vacuum melting is 1150-1250°C.

5. The preparation method according to claim 1, characterized in that: The inert atmosphere includes any one of an argon atmosphere, a nitrogen atmosphere, or a helium atmosphere.

6. The preparation method according to claim 1, characterized in that: The continuous casting speed of the directional solidification continuous casting is 5 to 20 cm / min.

7. The preparation method according to claim 1, characterized in that: The cooling method of the directional solidification continuous casting is water cooling, the water inlet temperature is 20-30° C., and the water flow rate is 1-5 LPM.

8. The preparation method according to claim 1, characterized in that: The raw copper includes electrolytic copper or pure copper, and the raw silver is pure silver.

9. A copper-silver alloy with low oxygen content, characterized in that: Prepared by the preparation method according to any one of claims 1 to 8; Preferably, the copper-silver alloy is a copper-silver alloy wire blank with a diameter of 6 to 8 mm.

10. A use of the copper-silver alloy as claimed in claim 9 in preparing high-strength and high-conductivity copper-silver alloy ultrafine wire, characterized in that: The diameter of the high-strength and high-conductivity copper-silver alloy ultrafine wire is less than 30 μm.

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