Preparation method of gold-spraying wire without coarse crystal layer

Abstract

The present invention belongs to the field of electronic materials and specifically discloses a method for preparing a gold-sprayed wire without a coarse-grained layer. The method comprises the following steps: S1: melting the raw materials for preparing the gold-sprayed wire and casting them using a hot-top semi-continuous casting method, followed by cooling and forming the resulting cast rod at a cooling rate of no less than 8°C / s; S2: extruding the cast rod at 180-250°C. The method for preparing the gold-sprayed wire eliminates the rolling step, further simplifying the preparation process and achieving a short, high-efficiency process for preparing the gold-sprayed wire. This process is environmentally friendly and low-carbon. Furthermore, by optimizing the extrusion step, the material's deformation energy storage is reduced, the formation of a coarse-grained layer in the gold-sprayed wire is avoided, the grain size and the size of the precipitated second phase are controlled, and the mechanical strength and elongation of the gold-sprayed wire are improved.

Description

Technical Field

[0001] The invention belongs to the field of electronic materials, and in particular relates to a method for preparing a gold-spraying wire without a coarse-grained layer. Background Art

[0002] Metallized film capacitors are commonly used electronic devices, and the quality of their end-face gold coating significantly impacts their lifespan and charge / discharge performance. Tin-zinc alloys offer a low melting point, excellent conductivity, and low specific resistivity. They also possess moderate strength and good plasticity, making them suitable for deformation processing. With the rapid development of lead-free electronic materials, the use of tin-zinc gold-sprayed wire is rapidly increasing.

[0003] At present, the main production process of tin-zinc spray gold wire includes the following steps:

[0004] 1) Casting: The ingot is produced by gravity casting with a metal mold. The ingot diameter is generally 80mm-100mm;

[0005] 2) Extrusion: After the ingot is heated, it is extruded to obtain a round rod blank. The diameter of the round rod blank is generally 6mm-15mm;

[0006] 3) Rolling: After annealing, the round bar blank is rolled into a wire rod blank and further reduced in diameter. The diameter of the wire rod blank is 3.5-4.5mm;

[0007] 4) Drawing: The rolled wire rod blank is annealed and then drawn into a sprayed gold wire with a diameter of 1.0mm-3.2mm.

[0008] The above production method is complex, and the billet undergoes two deformation passes, extrusion and rolling, which can lead to abnormal grain growth and the formation of a coarse-grained layer on the surface of the spray wire, severely reducing the mechanical properties of the wire. Furthermore, ingots produced by gravity casting using metal molds have a rough surface, poor solidification structure, and numerous inclusions and porosity defects. Round rods extruded using this method exhibit numerous surface defects such as porosity and burrs, and high wire breakage rates during rolling and drawing, severely impacting production efficiency and economic benefits. Summary of the Invention

[0009] In order to overcome the problems existing in the prior art, one of the objectives of the present invention is to provide a method for preparing a gold-spraying wire.

[0010] A second object of the present invention is to provide a tin-zinc gold-sprayed wire.

[0011] A third object of the present invention is to provide a method for preparing a gold-spraying wire and / or the application of the tin-zinc gold-spraying wire in electronic devices.

[0012] In order to achieve the above object, the technical solution adopted by the present invention is:

[0013] A first aspect of the present invention provides a method for preparing a gold-spraying wire, comprising the following steps:

[0014] S1: After the raw materials for the spray gold wire are melted, they are cast using a hot top semi-continuous casting method, and then cooled at a cooling rate of not less than 8°C / s to obtain a cast rod;

[0015] S2: Extruding the cast rod at 180-250°C.

[0016] Preferably, the cooling rate is 8-12°C / s, for example, 8°C / s, 8.5°C / s, 9°C / s, 9.5°C / s, 10°C / s, 10.5°C / s, 11°C / s, 11.5°C / s, 12°C / s, or any value between any two of the aforementioned endpoints. The cooling intensity during casting affects the grain size and secondary dendrite arm spacing of the cast rod, which in turn affects the tensile strength and elongation of the sprayed wire. To avoid the formation of coarse cast microstructures, the cooling intensity during casting is ≥8°C / s, resulting in a cast rod grain size of ≤150 μm and a secondary dendrite arm spacing of ≤25 μm.

[0017] In the present invention, the cast rod is extruded at 180-250°C, for example, it can be selected from 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C or any value within the range of any two endpoints. Extrusion is a key process that affects whether the gold-sprayed wire forms coarse grains. When the extrusion temperature is too low, the deformation energy storage of the material is large, and a coarse grain layer is likely to appear. Therefore, the preparation method of the present invention needs to ensure that the extrusion molding temperature is 180-250°C. If the temperature is lower than 180°C, a coarse grain layer is likely to appear. If the temperature is higher than 250°C, cracks are likely to form on the surface of the extruded product, and in severe cases, the product will directly break.

[0018] Preferably, the preparation method further includes step S3, which is located after step S2 and comprises annealing at 120-180°C and then drawing. For example, the annealing temperature can be selected from 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, or any value within the range of any two of the above endpoints. If the specifications of the product obtained after extrusion molding in step S2 meet the requirements for gold-sprayed wire, step S3 is not required. If the specifications of the product obtained after extrusion molding in step S2 do not meet the requirements for gold-sprayed wire, step S3 is required, and after further drawing in S3, gold-sprayed wire that meets the specification requirements is produced.

[0019] Preferably, the annealing holding time is 1 to 3 hours, for example, can be selected from 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours or any value within the range of any two endpoints thereof.

[0020] At the aforementioned annealing temperature and time, the precipitated phase in the microstructure of the annealed product is kept ≤20μm in length and ≤3μm in width, which improves the mechanical properties of the drawn spray-coated wire. Insufficient annealing temperature and holding time result in a small amount of precipitated secondary phase, which is detrimental to improving the strength of the spray-coated wire. Excessively high annealing temperature or long holding time increases the size of the precipitated phase, hindering improvements in the strength and elongation of the spray-coated wire.

[0021] Preferably, the diameter of the cast rod in step S1 is 80 to 154 mm, for example, it can be selected from 80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 154 mm, or any value within the range of any two of the above endpoints. If the cast rod specification is too large, that is, the diameter exceeds 154 mm, the temperature difference between the surface and the interior of the cast rod is too large, and low-melting-point tin-rich segregation nodules are likely to appear on the surface of the cast rod, resulting in serious segregation of the cast rod composition and affecting subsequent extrusion. At the same time, if the diameter of the cast rod exceeds 154 mm, the cooling rate of the center of the cast rod is low during solidification, the grains are coarse, and coarse grain rings are likely to appear during extrusion. If the cast rod specification is too small, that is, the diameter of the cast rod is less than 80 mm, casting is difficult, and the melt is likely to solidify at the hot top position, resulting in casting failure.

[0022] Preferably, the diameter of the cast rod after processing in step S2 is 2.5 mm to 3.5 mm, for example, it can be selected from 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm or any value within the range of any two endpoints of the above.

[0023] Preferably, the diameter of the gold-spraying wire is 1 to 3.2 mm, for example, it can be selected from 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm, 2.9 mm, 3 mm, 3.1 mm, 3.2 mm or any value within the range of any two of the above endpoints.

[0024] Preferably, the gold-spraying wire comprises a tin-zinc gold-spraying wire.

[0025] Preferably, the melting temperature in step S1 is 400-650°C, for example, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, or any value within the range of any two of the above endpoints. If the melting temperature is too high, it is easy to cause volatilization and burning of elements such as zinc and tin, thereby resulting in waste of raw materials.

[0026] Preferably, in the melting step in step S1, the metal material with a low melting point is first placed at the bottom of the heating furnace, and the metal material with a high melting point is placed at the top of the heating furnace, and the metal materials are heated to melt and mix.

[0027] Preferably, the casting step in step S1 uses a crystallizer whose cooling belt is made of graphite.

[0028] Preferably, the casting temperature in step S1 is 400-550°C, for example, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, or any value between any two of the foregoing endpoints. Excessively high casting temperatures can easily result in coarse grain structure in the cast rod, affecting the mechanical properties of the sprayed wire. Excessively low casting temperatures can easily lead to defects such as cold shuts on the cast rod surface.

[0029] Preferably, the step S1 is: heating the raw materials for preparing the gold spray wire to 400-650°C for melting, refining and filtering to obtain a melt; then casting the melt by a hot top semi-continuous casting method, and then cooling and forming it at a cooling rate of not less than 8°C / s; further preferably, preferably, the step S1 is: heating the raw materials for preparing the gold spray wire to 400-650°C for melting, refining and letting it stand, and then filtering to obtain a melt; then casting the melt by a hot top semi-continuous casting method, and then cooling and forming it at a cooling rate of not less than 8°C / s.

[0030] Preferably, the refining is performed using at least one of high-purity nitrogen, high-purity argon, and a refining agent.

[0031] Preferably, the refining time is 5 to 15 minutes.

[0032] Preferably, the standing time is 10 to 30 minutes. The standing step is to allow the slag and gas to float, which is beneficial for removing the slag.

[0033] Preferably, the filtration adopts at least one of plate filtration and tubular filtration.

[0034] Preferably, the filtering step adopts online filtration.

[0035] Preferably, the particle size of inclusions contained in the filtered melt does not exceed 1 μm.

[0036] Preferably, the proportion of the area of the slag inclusions to the cross-sectional area of the gold spraying wire does not exceed 5%.

[0037] The second aspect of the present invention provides a tin-zinc gold-sprayed wire, which comprises the following components in mass percentage: 20-90% tin and 10-80% zinc; the tin-zinc gold-sprayed wire is prepared by the preparation method of the gold-sprayed wire described in the first aspect of the present invention.

[0038] In the present invention, the mass percentage of tin in the tin-zinc gold-sprayed wire is 20-90%, for example, it can be selected from 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or any value within the range of any two of the above endpoints.

[0039] In the present invention, the mass percentage of zinc in the tin-zinc gold-sprayed wire is 10-80%, for example, it can be selected from 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or any value within the range of any two of the above endpoints.

[0040] The tin-zinc gold-spraying wire comprises the following components in mass percentage: 20-89% tin, 10-79% zinc, and 0-5% trace elements which are not 0.

[0041] Preferably, the trace element is selected from at least one of copper and antimony.

[0042] Preferably, the tin-zinc gold-sprayed wire does not contain a coarse-grained layer.

[0043] Preferably, the tensile strength of the tin-zinc gold-sprayed wire is ≥173 MPa; further preferably, the tensile strength of the tin-zinc gold-sprayed wire is 173-200 MPa; even further preferably, the tensile strength of the tin-zinc gold-sprayed wire is 180.6-198.4 MPa.

[0044] Preferably, the yield strength of the tin-zinc gold-sprayed wire is ≥144 MPa; further preferably, the yield strength of the tin-zinc gold-sprayed wire is 144-180 MPa; even further preferably, the yield strength of the tin-zinc gold-sprayed wire is 161.1-173.5 MPa.

[0045] Preferably, the elongation after break of the tin-zinc gold-sprayed wire is ≥16.9%; further preferably, the elongation after break of the tin-zinc gold-sprayed wire is 16.9-30%; even further preferably, the elongation after break of the tin-zinc gold-sprayed wire is 25.4-26.7%.

[0046] Preferably, the grain size of the tin-zinc gold-spraying wire is ≤150 μm; further preferably, the grain size of the tin-zinc gold-spraying wire is 119-145 μm.

[0047] Preferably, the secondary dendrite arm spacing of the tin-zinc gold-sprayed wire is ≤25 μm; further preferably, the secondary dendrite arm spacing of the tin-zinc gold-sprayed wire is 15.8-23 μm.

[0048] Preferably, the length of the second phase precipitated in the tin-zinc gold-spraying wire is ≤23μm, and the width is ≤3.4μm; further preferably, the length of the second phase precipitated in the tin-zinc gold-spraying wire is 15.4~23μm, and the width is 2.1~3.4μm; even further preferably, the length of the second phase precipitated in the tin-zinc gold-spraying wire is 15.4~20μm, and the width is 2.1~2.8μm.

[0049] The third aspect of the present invention provides a method for preparing the gold-sprayed wire described in the first aspect of the present invention and / or use of the tin-zinc gold-sprayed wire described in the second aspect of the present invention in electronic devices.

[0050] The beneficial effects of the present invention are as follows: the preparation method of the gold-sprayed wire in the present invention reduces the rolling step, the preparation steps are further simplified, and a short process and high-efficiency preparation of the gold-sprayed wire is achieved. The preparation process is green and low-carbon. At the same time, by optimizing the extrusion step, the deformation energy storage of the material is reduced, the formation of a coarse-grained layer in the gold-sprayed wire is avoided, the grain size and the size of the precipitated second phase are controlled, and the mechanical strength and elongation of the gold-sprayed wire are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a 50-fold magnified SEM image of the cross section of the tin-zinc gold-sprayed wire prepared in Example 1.

[0052] Figure 2 This is a SEM image of the cross section of the tin-zinc gold-sprayed wire prepared in Example 1, magnified 500 times.

[0053] Figure 3 This is a SEM image of the cross section of the tin-zinc gold-sprayed wire prepared in Example 1, magnified 10,000 times.

[0054] Figure 4 This is a 50-fold magnified SEM image of the cross section of the wire blank obtained after extrusion in Comparative Example 1.

[0055] Figure 5This is a SEM image of the cross section of the tin-zinc gold-sprayed wire prepared in Comparative Example 1, magnified 1000 times. DETAILED DESCRIPTION

[0056] The specific implementation of the present invention will be further described in detail below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are any processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. The reagents or instruments used that do not indicate the manufacturer are all conventional products that can be purchased commercially.

[0057] In the hot top casting step (2) of Examples 1 to 10 of the present invention and Comparative Examples 2 to 4, cooling is performed using a crystallizer whose cooling belt is made of graphite, and the cooling medium is water.

[0058] Example 1

[0059] This example provides a method for preparing a tin-zinc gold-sprayed wire without a coarse-grained layer, which comprises the following steps:

[0060] (1) Melting: Place zinc ingots and tin ingots into a melting furnace. After melting, raise the temperature to 500°C and stir evenly. Use high-purity nitrogen for refining for 10 minutes. After skimming, let it stand and keep warm for 20 minutes to obtain a melt.

[0061] (2) The melt in step (1) was filtered using a 60-mesh ceramic filter plate, and cast rods with a diameter of 90 mm were produced by hot top casting at a casting temperature of 500° C. and a cooling rate of 12° C. / s.

[0062] (3) Extrusion: The billet is heated and then extruded. The temperature of the billet at the extrusion outlet is 210°C, and a billet with a diameter of 3 mm is obtained.

[0063] (4) Drawing: The wire billet is annealed at 150°C for 1.5 hours, air-cooled after being taken out of the furnace, and drawn to produce a gold-sprayed wire with a diameter of 1.8 mm, which is the tin-zinc gold-sprayed wire without a coarse grain layer in this example.

[0064] In the coarse-grained layer-free tin-zinc gold-spraying wire of this example, the mass percentage of tin is 30%, the unavoidable impurity elements are less than 0.1%, and Zn is the balance.

[0065] Example 2

[0066] The preparation method of the coarse-grained layer-free tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the cooling rate in step (2) of this example is 8° C. / s.

[0067] Example 3

[0068] The preparation method of the coarse-grained layer-free tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the cooling rate in step (2) of this example is 10° C. / s.

[0069] Example 4

[0070] The preparation method of the coarse-grained layer-free tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the wire billet temperature at the extrusion outlet in step (3) of this example is 240°C.

[0071] Example 5

[0072] The preparation method of the coarse-grained layer-free tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the wire blank is annealed at 170°C in step (4) of this example.

[0073] Example 6

[0074] The preparation method of the coarse-grained layer-free tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the wire blank is annealed at 120°C in step (4) of this example.

[0075] Example 7

[0076] The preparation method of the coarse-grained layer-free tin-zinc sprayed gold wire in this example is different from that in Example 1 only in that the wire blank is kept warm for 1 hour in step (4) of this example.

[0077] Example 8

[0078] The preparation method of the coarse-grained layer-free tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the wire blank is kept warm for 2 hours in step (4) of this example.

[0079] Example 9

[0080] The preparation method of the coarse-grained layer-free tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the wire blank is annealed at 100° C. in step (4) of this example.

[0081] Example 10

[0082] The preparation method of the coarse-grained layer-free tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the wire blank is annealed at 200°C in step (4) of this example.

[0083] Comparative Example 1

[0084] The preparation method of the tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the ingot in step (2) of this example is cast by conventional gravity casting, the casting temperature is 600°C, and the cooling rate during solidification of the ingot is 6°C / s.

[0085] Comparative Example 2

[0086] The preparation method of the tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the cooling rate in step (2) of this example is 6.5° C. / s.

[0087] Comparative Example 3

[0088] The preparation method of the tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the temperature of the wire billet at the extrusion outlet in step (3) of this example is 160°C.

[0089] Comparative Example 4

[0090] The preparation method of the tin-zinc gold-sprayed wire in this example is different from that in Example 1 only in that the temperature of the wire billet at the extrusion outlet in step (3) of this example is 270°C.

[0091] The SEM images of the cross section of the tin-zinc sprayed gold wire prepared in Example 1 were magnified 50 times, 500 times and 10,000 times respectively by scanning electron microscopy. The test results are as follows: Figures 1 to 3 The SEM image of the wire billet obtained after extrusion in Comparative Example 1 was tested using a scanning electron microscope. Figure 4 As shown, the SEM image of the cross section of the tin-zinc sprayed gold wire obtained after drawing in Comparative Example 1 was tested. Figure 5 As shown. Figure 1 It can be seen that when the cross section of the tin-zinc sprayed gold wire prepared in Example 1 is magnified 50 times, the sprayed gold wire structure is still uniform and dense, and no coarse grain layer appears at the edge. Figure 2 It can be seen that when the cross section of the tin-zinc sprayed gold wire prepared in Example 1 is magnified 500 times, the precipitated phase ( Figure 2 The white in the middle is the precipitated phase, the gray is the matrix) and the precipitated phase is evenly distributed, with an average length of about 8μm and a width of about 1μm. Figure 3 It can be seen that when the cross section of the tin-zinc sprayed gold wire prepared in Example 1 is magnified 10,000 times, oxide inclusions with a particle size of less than 1 μm can be observed (see Figure 3 The black part in the figure) and the precipitated phase (see Figure 3 (white part in the middle). Figure 4 It can be seen that the surface layer of the wire blank obtained by extrusion in Comparative Example 1 has bubble defects. Figure 5 It can be seen that the tin-zinc gold-sprayed wire prepared in Comparative Example 1 has defects such as inclusions and cracks.

[0092] The tin-zinc gold-sprayed wires prepared in Examples 1-10 and Comparative Examples 1-4 were cut along cross sections, electrolytically polished, and then observed under polarized light. Data on grain size, secondary dendrite arm spacing, precipitated second phase size, and coarse-grained layer thickness were collected. Scanning electron microscopy (SEM) was used to randomly photograph at least 10 fields of view at a magnification of 1000x. For each field of view, at least five second phases were randomly measured. The length and width of all measured particles were then averaged to obtain the size of the precipitated second phase.

[0093] The secondary dendrite arm spacing was measured using the line-intercept method. A scanning electron microscope (SEM) was used to randomly photograph at least 10 fields of view at a magnification of 1000x. For each field of view, at least five secondary dendrite arm spacings were randomly measured. The secondary dendrite arm spacing was then calculated as the ratio of all measured straight line lengths to the number of secondary diameter spacings.

[0094] The specific test results are shown in Table 1. The results of the preparation methods of Examples 1 to 10 and Comparative Examples 1 to 4 when drawing and preparing tin-zinc sprayed gold wires are recorded, as shown in Table 1.

[0095] Table 1 Microstructure characteristics and drawing results of gold-sprayed wire

[0096]

[0097]

[0098] As shown in Table 1, compared with Comparative Example 1, Examples 1 to 10 of the present invention use a hot top casting method instead of the traditional gravity casting method. The grain size, secondary dendrite arm spacing, and precipitated second phase size of the resulting tin-zinc gold-sprayed wire are all smaller, and there is no coarse grain layer. During the drawing process, the wire can be drawn normally with an extremely low wire breakage rate. Compared with Examples 1 to 10, the cooling rate during casting in Comparative Example 2 is too low, and the grain size, secondary dendrite arm spacing, and precipitated second phase size of the resulting tin-zinc gold-sprayed wire are all larger. A coarse grain layer also exists in the gold-sprayed wire, and a small amount of wire breakage occurs during the drawing process. The wire billet temperature at the extrusion outlet of Comparative Example 3 is too low, and the resulting tin-zinc gold-sprayed wire has a thick coarse grain layer and a high wire breakage rate during drawing. The wire billet temperature at the extrusion outlet of Comparative Example 4 is too high, and the resulting precipitated second phase size of the resulting tin-zinc gold-sprayed wire is larger, cracks appear on the gold-sprayed wire surface, and the wire breakage rate is high during drawing.

[0099] The mechanical properties of the tin-zinc gold-sprayed wires prepared in Examples 1 to 10 and Comparative Examples 1 to 4 were tested, and the specific test methods are shown in Table 2 below.

[0100] Table 2 Mechanical properties test results of tin-zinc sprayed gold wire

[0101]

[0102]

[0103] As can be seen from Table 2, compared with comparative examples 1 to 4, the tin-zinc gold-sprayed wires prepared in Examples 1 to 8 of the present invention have higher tensile strength, yield strength and elongation after fracture, specifically: tensile strength is 180.6 to 198.4 MPa, yield strength is 161.1 to 173.5 MPa, and elongation after fracture is 25.4 to 26.7%.

[0104] In summary, compared with the traditional method, the tin-zinc spray-gold wire preparation method of the present invention reduces the rolling step, the preparation step is more simplified, and a short process for preparing the spray-gold wire is achieved. The preparation process is green and low-carbon. At the same time, by optimizing the extrusion step, the deformation energy storage of the material is reduced, the formation of a coarse grain layer in the spray-gold wire is avoided, the grain size and the size of the precipitated second phase are controlled, and the mechanical strength and elongation of the spray-gold wire are improved, so that the tensile strength of the prepared tin-zinc spray-gold wire is 173-200MPa, the yield strength is 144-180MPa, and the elongation after fracture is 16.9-30%. In addition, the preparation method of the present invention controls impurities in the spray-gold wire by optimizing the melt treatment and casting process, significantly reduces the wire breakage rate during drawing, and improves production efficiency and economic benefits.

[0105] While the embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above. Various modifications may be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof may be combined with one another unless there is a conflict.

Claims

1. A method for preparing a gold-spraying wire, characterized in that: The following steps are involved: S1: After melting the raw materials for preparing the gold spray wire, the raw materials are cast using a hot top semi-continuous casting method, and then cooled at a cooling rate of 8 to 12°C / s to obtain a cast rod; the casting temperature in step S1 is 400 to 550°C; S2: Extruding the cast rod at 180-250° C. S3: annealing at 120-180°C, followed by drawing; The preparation method does not contain a rolling step.

2. The method for preparing the gold-spraying wire according to claim 1, wherein: The annealing time is 1 to 3 hours.

3. The method for preparing the gold-sprayed wire according to claim 1, wherein: The diameter of the cast rod in step S1 is 80-154 mm; and / or, the diameter of the cast rod after processing in step S2 is 2.5 mm to 3.5 mm; And / or, the diameter of the gold-spraying wire is 1-3.2 mm.

4. The method for preparing the gold-spraying wire according to claim 1, wherein: The gold-spraying wire comprises a tin-zinc gold-spraying wire.

5. The method for preparing the gold-spraying wire according to claim 1, wherein: The melting temperature in step S1 is 400-650°C; And / or, the casting step in step S1 uses a crystallizer whose cooling zone is made of graphite.

6. The method for preparing the gold-sprayed wire according to claim 1, wherein: The step S1 comprises heating the raw materials for preparing the gold spray wire to 400-650° C. for melting, refining and filtering to obtain a melt; then casting the melt by a hot top semi-continuous casting method, and cooling the melt at a cooling rate of 8-12° C. / s to form the melt.

7. A tin-zinc gold-sprayed wire, characterized in that: The tin-zinc gold-spraying wire comprises the following components in mass percentage: 20-90% tin and 10-80% zinc; the tin-zinc gold-spraying wire is prepared by the preparation method of the gold-spraying wire according to any one of claims 1 to 6.

8. The tin-zinc gold-spraying wire according to claim 7, characterized in that: The tin-zinc gold spraying wire has at least one of the following characteristics: (a) the tin-zinc gold-sprayed wire does not contain a coarse-grained layer; (b) the tensile strength of the tin-zinc sprayed gold wire is ≥173 MPa; (c) the yield strength of the tin-zinc sprayed gold wire is ≥144 MPa; (d) the elongation after fracture of the tin-zinc gold-sprayed wire is ≥16.9%; (e) The grain size of the tin-zinc gold-sprayed wire is ≤150 μm; (f) the secondary dendrite arm spacing of the tin-zinc gold-sprayed wire is ≤25 μm; (g) The second phase precipitated in the Sn-Zn gold-sprayed wire has a length of ≤23 μm and a width of ≤3.4 μm.

9. A method for preparing the gold-spraying wire according to any one of claims 1 to 6 and / or use of the tin-zinc gold-spraying wire according to any one of claims 7 to 8 in electronic devices.

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