Environment-friendly superfine solder wire and preparation method thereof

Abstract

The invention discloses an environment-friendly superfine solder wire and a preparation method thereof, belongs to the technical field of solder wires, and aims to solve the technical problems of insufficient performance and size limitation of the solder wire in the prior art. The environment-friendly superfine solder wire comprises a flux core and an outer film layer, wherein the outer film layer covers the exterior of the flux core; the flux core is composed of a third element alloy and a soldering flux; the third element alloy comprises the following components: tin Sn, bismuth Bi and an element alloy; the element alloy components comprise gallium Ga, indium In, cobalt Co and nickel Ni; the scaling powder comprises a carrier, an activating agent, a surface active agent, a thixotropic agent and a corrosion inhibitor. And the outer film layer is prepared by compounding and blending a zinc compound and phenolic resin according to a compounding ratio of 2: 1 to 1: 1. The environment-friendly superfine solder wire has the advantages of being low in melting point, good in wettability, excellent in crack propagation resistance and corrosion resistance and the like, can meet the requirement for narrow-interval welding of a microcomputer, and provides a high-reliability interconnection material for welding for electronic products.

Description

Technical Field

[0001] The invention belongs to the technical field of solder wires, and in particular relates to an environmentally friendly ultra-fine solder wire and a preparation method thereof. Background Art

[0002] Solder wire, also known as solder wire, tin wire or tin wire, is composed of tin alloy and flux. The alloy components are mainly divided into tin-lead alloy and lead flux, as well as tin-copper alloy and lead-free flux. The main function of solder wire is to serve as a filler for welding and fix electronic components. As a key technology for connecting metals or metals with other materials, welding technology plays an important role in industrial production. With the advancement of science and technology, the development of welding material products has shown obvious trends in composition, cost performance and product size: the composition is developing towards lead-free, halogen-free, environmentally friendly and functional, which is to meet the increasingly stringent environmental regulations and meet the needs of electronic products for high performance and high reliability. The cost performance is developing towards reliable quality and low cost. This requires welding materials to optimize production processes and reduce costs while ensuring performance, and the product size is developing towards ultra-fine and narrower distribution span.

[0003] With the rapid development of electronic products and their technologies, the requirements for welding materials are becoming more and more stringent, especially for micro electronic assemblies (SMT), circuit boards, components, micro connectors, and infrared process welds with a solder joint spacing of less than or equal to Φ0.2mm. The required solder wire must be less than or equal to Φ0.12mm. Otherwise, two solder joints are prone to bridge, causing components and circuits to short-circuit. Although the existing solder wire products have met the market demand to a certain extent, they still have the following problems in more refined products and high-end application fields such as microcomputers: Insufficient performance: Some solder wire products have high melting points, poor wettability, insufficient crack propagation resistance and corrosion resistance due to the limitations of alloy composition and preparation process; Size limitation: Traditional solder wire preparation processes are difficult to produce ultra-fine solder wires with a diameter of less than Φ0.12mm, which cannot meet the high-precision welding requirements of micro electronic assemblies. In view of the above problems, it is particularly important to develop a lead-free environmentally friendly ultra-fine solder wire with low melting point, good wettability, excellent crack propagation resistance and corrosion resistance and its preparation method. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an environmentally friendly ultra-fine solder wire and a preparation method thereof, aiming to solve the technical problems of insufficient performance and size limitations of solder wire in the prior art.

[0005] Technical Solution

[0006] In order to solve the above technical problems, the present invention provides an environmentally friendly ultra-fine solder wire, comprising a flux core and an outer film layer, wherein the outer film layer is coated on the outside of the flux core;

[0007] The flux core is composed of a third element alloy and a flux, and the components of the third element alloy include:

[0008] Tin Sn, bismuth Bi, element alloys;

[0009] The element alloy components include: gallium Ga, indium In, cobalt Co, nickel Ni;

[0010] The components of the soldering flux include:

[0011] Carriers, activators, surfactants, thixotropic agents and corrosion inhibitors;

[0012] Preferably, the outer film layer is made by compounding and blending the zinc compound and the phenolic resin in a proportion of 2:1 to 1:1.

[0013] Preferably, the outer film layer is made by compounding and blending the zinc compound and the polyurethane in a proportion of 2:1 to 1:1.

[0014] Preferably, the weight proportion of each component in the third element alloy is:

[0015] Tin (Sn) accounts for 54.0% to 64.5%, bismuth (Bi) accounts for 29.7% to 39.8%, and element alloy accounts for 2.3% to 3.7%, with a total proportion of 100%.

[0016] Preferably, the weight ratio of each component in the elemental alloy to the total weight of the tin wire is:

[0017] Gallium Ga accounts for 0.05% to 0.1wt%, indium In accounts for 0.15% to 0.33wt%, cobalt Co accounts for 0.15% to 0.24wt%, and nickel Ni accounts for 1.7% to 3.32wt%.

[0018] Preferably, the weight proportion of each component in the flux is:

[0019] The carrier accounts for 65% to 80%, the activator accounts for 6% to 15%, the surfactant accounts for 5% to 16%, the thixotropic agent accounts for 1% to 2.85%, the corrosion inhibitor accounts for 0.46% to 6.32%, and the total proportion is 100%.

[0020] Preferably, the carrier in the soldering flux is a mixture of esterified rosin, graphene dispersion and propylene glycol.

[0021] Preferably, the weight percentages of the components in the carrier in the soldering flux are:

[0022] The esterified rosin accounts for 55% to 72%, the graphene dispersion accounts for 0.5% to 10%, and the propylene glycol accounts for 1% to 5%.

[0023] Preferably, the corrosion inhibitor in the soldering flux is one or a mixture of methylbenzotriazole and OP-10, and the weight percentages of the components of the corrosion inhibitor in the soldering flux are respectively:

[0024] Tolyltriazole 0% to 1.87%, OP-10 0% to 5%.

[0025] A method for preparing an environmentally friendly ultra-fine solder wire comprises the following steps:

[0026] Step 1: Raw material preparation and smelting: weigh tin Sn, bismuth Bi and elemental alloy raw materials according to weight ratio, melt and heat these raw materials to 380-400°C, perform heat preservation, stirring, standing and slag removal, and then cast a cylindrical billet with a specification of Φ84×180mm;

[0027] Step 2: Coarse wire extrusion, put the Φ84×180mm rod blank into a 350-ton large deformation extruder with a wire outlet diameter of Φ9mm, and at the same time add rosin welding oil into the rosin barrel at a ratio of 2.0% to 2.6%, control the rosin barrel temperature at 110℃, the rod blank temperature at 100℃, and the extrusion pressure at 150kg / cm 2 , the wire speed is about 1.5m / min, adjust the centering and gap size of the rosin nozzle, and test the flux content of the thick wire until the flux content of the core of the thick tin wire reaches 2.0% to 2.6%;

[0028] Step 3: Rolling forming: insert the Φ9mm thick tin wire into the 16-pass near-final forming roller mill to roll out the Φ3.0mm solder wire;

[0029] Step 4: Fine drawing and coating. The Φ3.0mm near-final finished solder wire with a nearly circular cross section is sequentially passed through three wire drawing machines with 28 diamond drawing dies for drawing. The first wire drawing machine draws the solder wire to Φ0.8mm, the second wire drawing machine draws the solder wire to Φ0.3mm, and the third wire drawing machine draws the solder wire into the final finished solder wire size of Φ0.10mm. After the solder wire completely passes through the second wire drawing machine, the coating process is carried out. The solder wire quickly passes through a film-forming molten liquid composed of zinc compounds and phenolic resin or polyurethane (the solution temperature is between 45 and 55°C), and the surface of the solder wire is cooled to form a film.

[0030] Step 5: Brightening and anti-oxidation treatment: the coated solder wire is passed through a water tank with a cleaning tank for brightening and anti-oxidation treatment. The cleaning agent is 5% to 10% ST-010 saponification liquid, and the anti-oxidation coating agent is 2% to 5% dodecyl hydroxystearic acid alcohol solution;

[0031] Step 6: Subsequent processing: the drawn ultra-fine solder wire is dried in the shade, wound, packaged and stored.

[0032] Beneficial Effects

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The solder wire provided by the present invention has the characteristics of low melting point, good wettability, excellent crack propagation resistance and corrosion resistance, etc., can meet the narrow spacing welding requirements of microcomputers, and provide highly reliable welding interconnection materials for electronic products.

[0035] By optimizing the alloy composition, especially adding appropriate amounts of Bi and element alloys (gallium Ga, indium In, cobalt Co, nickel Ni), the melting point of the solder wire is reduced, so that welding can be completed at a lower temperature and energy can be saved; the composition of the flux is reasonably designed, especially the ratio of the carrier, activator, surfactant, thixotropic agent and corrosion inhibitor, so that the solder wire has good wettability and flow characteristics during the welding process, which can ensure the welding quality; the alloy components and flux in the solder wire work together to make the welded joint have good toughness and crack propagation resistance, thereby improving the reliability of the welded joint; by adding specific alloy elements and flux components, the corrosion resistance of the solder wire is improved, so that the welded joint can operate stably for a long time under harsh environments. In addition, the solder wire does not contain harmful substances such as lead, and no harmful gases are generated during the welding process, which meets environmental protection requirements and is beneficial to protecting the environment and human health. Since the diameter of the solder wire is ultra-fine (Φ0.10mm), high-precision welding can be achieved, which is suitable for the narrow pitch welding needs of microcomputers, improving the reliability and stability of electronic products, and the small diameter of the ultra-fine solder wire can minimize the risk of solder bridges between adjacent connections, reduce short circuits and ensure reliable electrical performance. The ultra-fine solder wire can promote rapid heat transfer, speed up the welding process, reduce thermal stress on sensitive components, and is beneficial to protecting welding joints and surrounding components. Therefore, the solder wire can be suitable for occasions requiring high-precision welding, such as surface mount technology (SMT), microelectronics, medical equipment, aerospace and defense. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 This is a structural diagram of the environmentally friendly ultra-fine solder wire of the present invention;

[0038] Figure 2 is a structural block diagram of the third element alloy in the present invention;

[0039] Figure 3 It is a structural diagram of the element alloy of the present invention;

[0040] Figure 4 It is a structural block diagram of the soldering flux in the present invention;

[0041] Figure 5 The figure is a flow chart of the method for preparing the environmentally friendly ultrafine solder wire in the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] This embodiment provides an environmentally friendly ultra-fine solder wire, and its structural flow chart is as follows Figure 1-Figure 4 As shown, it includes a drug core and an outer film layer, wherein the outer film layer covers the outside of the drug core;

[0044] The flux core is composed of a third element alloy and a flux, and the components of the third element alloy include:

[0045] Tin Sn, bismuth Bi, element alloys;

[0046] The element alloy components include: gallium Ga, indium In, cobalt Co, nickel Ni;

[0047] The components of the soldering flux include:

[0048] Carriers, activators, surfactants, thixotropic agents and corrosion inhibitors;

[0049] Furthermore, in this embodiment, the outer film layer is made by compounding and blending a zinc compound and a phenolic resin in a proportion of 2:1 to 1:1.

[0050] Furthermore, in this embodiment, the outer film layer is made by compounding and blending a zinc compound and a polyurethane in a proportion of 2:1 to 1:1.

[0051] Furthermore, in this embodiment, the weight proportions of the components in the third element alloy are:

[0052] Tin (Sn) accounts for 54.0% to 64.5%, bismuth (Bi) accounts for 29.7% to 39.8%, and element alloy accounts for 2.3% to 3.7%, with a total proportion of 100%.

[0053] Furthermore, in this embodiment, the weight ratio of each component in the element alloy to the total weight of the tin wire is:

[0054] Gallium Ga accounts for 0.05% to 0.1wt%, indium In accounts for 0.15% to 0.33wt%, cobalt Co accounts for 0.15% to 0.24wt%, and nickel Ni accounts for 1.7% to 3.32wt%.

[0055] Furthermore, in this embodiment, the weight proportions of the components in the soldering flux are:

[0056] The carrier accounts for 65% to 80%, the activator accounts for 6% to 15%, the surfactant accounts for 5% to 16%, the thixotropic agent accounts for 1% to 2.85%, the corrosion inhibitor accounts for 0.46% to 6.32%, and the total proportion is 100%.

[0057] Furthermore, in this embodiment, the carrier in the flux is a mixture of esterified rosin, graphene dispersion, and propylene glycol.

[0058] The weight percentages of the components in the carrier in the flux are:

[0059] The esterified rosin accounts for 55% to 72%, the graphene dispersion accounts for 0.5% to 10%, and the propylene glycol accounts for 1% to 5%.

[0060] Further, in this embodiment, the corrosion inhibitor in the soldering flux is one or a mixture of methylbenzotriazole and OP-10, and the weight percentages of the components of the corrosion inhibitor in the soldering flux are respectively:

[0061] Tolyltriazole 0% to 1.87%, OP-10 0% to 5%.

[0062] This embodiment also provides an environmentally friendly method for preparing ultra-fine solder wire, and the method flow chart is as follows: Figure 5 As shown, the following steps are included:

[0063] Step 1: Raw material preparation and smelting: weigh tin Sn, bismuth Bi and elemental alloy raw materials according to weight ratio, melt and heat these raw materials to 380-400°C, perform heat preservation, stirring, standing and slag removal, and then cast a cylindrical billet with a specification of Φ84×180mm;

[0064] Step 2: Coarse wire extrusion, put the Φ84×180mm rod blank into a 350-ton large deformation extruder with a wire outlet diameter of Φ9mm, and at the same time add rosin welding oil into the rosin barrel at a ratio of 2.0% to 2.6%, control the rosin barrel temperature at 110℃, the rod blank temperature at 100℃, and the extrusion pressure at 150kg / cm 2, the wire speed is about 1.5m / min, adjust the centering and gap size of the rosin nozzle, and test the flux content of the thick wire until the flux content of the core of the thick tin wire reaches 2.0% to 2.6%;

[0065] Step 3: Rolling forming: insert the Φ9mm thick tin wire into the 16-pass near-final forming roller mill to roll out the Φ3.0mm solder wire;

[0066] Step 4: Fine drawing and coating. The Φ3.0mm near-final finished solder wire with a nearly circular cross section is sequentially passed through three wire drawing machines with 28 diamond drawing dies for drawing. The first wire drawing machine draws the solder wire to Φ0.8mm, the second wire drawing machine draws the solder wire to Φ0.3mm, and the third wire drawing machine draws the solder wire into the final finished solder wire size of Φ0.10mm. After the solder wire completely passes through the second wire drawing machine, the coating process is carried out. The solder wire quickly passes through a film-forming molten liquid composed of zinc compounds and phenolic resin or polyurethane (the solution temperature is between 45 and 55°C), and the surface of the solder wire is cooled to form a film.

[0067] Step 5: Brightening and anti-oxidation treatment: the coated solder wire is passed through a water tank with a cleaning tank for brightening and anti-oxidation treatment. The cleaning agent is 5% to 10% ST-010 saponification liquid, and the anti-oxidation coating agent is 2% to 5% dodecyl hydroxystearic acid alcohol solution;

[0068] Step 6: Subsequent processing: the drawn ultra-fine solder wire is dried in the shade, wound, packaged and stored.

[0069] Through the above preparation method, an environmentally friendly ultrafine solder wire can be obtained. The solder wire has the characteristics of low melting point, good wettability, excellent crack propagation resistance and corrosion resistance, etc. It can meet the narrow pitch welding requirements of microcomputers and provide highly reliable welding interconnection materials for electronic products.

[0070] Specifically, by optimizing the alloy composition, especially adding an appropriate amount of Bi and element alloys (gallium Ga, indium In, cobalt Co, nickel Ni), the melting point of the solder wire is reduced, so that welding can be completed at a lower temperature, saving energy; the composition of the flux is reasonably designed, especially the ratio of the carrier, activator, surfactant, thixotropic agent and corrosion inhibitor, so that the solder wire has good wettability and flow characteristics during the welding process, which can ensure the welding quality; the alloy components and flux in the solder wire work together to make the welded joint have good toughness and crack propagation resistance, thereby improving the reliability of the welded joint; by adding specific alloy elements and flux components, the corrosion resistance of the solder wire is improved, so that the welded joint can operate stably for a long time in harsh environments. In addition, the solder wire does not contain harmful substances such as lead, and no harmful gases are generated during the welding process, which meets environmental protection requirements and is beneficial to protecting the environment and human health. Since the diameter of the solder wire is ultra-fine (Φ0.10mm), high-precision welding can be achieved, which is suitable for the narrow pitch welding needs of microcomputers, improving the reliability and stability of electronic products, and the small diameter of the ultra-fine solder wire can minimize the risk of solder bridges between adjacent connections, reduce short circuits and ensure reliable electrical performance. The ultra-fine solder wire can promote rapid heat transfer, speed up the welding process, reduce thermal stress on sensitive components, and is beneficial to protecting welding joints and surrounding components. Therefore, the solder wire can be suitable for occasions requiring high-precision welding, such as surface mount technology (SMT), microelectronics, medical equipment, aerospace and defense.

[0071] All technical features in this embodiment can be freely combined according to actual needs.

[0072] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An environmentally friendly ultra-fine solder wire, characterized by: It includes a drug core and an outer film layer, wherein the outer film layer covers the outside of the drug core; The flux core is composed of a third element alloy and a flux, and the components of the third element alloy include: Tin Sn, bismuth Bi, element alloys; The element alloy components include: gallium Ga, indium In, cobalt Co, nickel Ni; The components of the soldering flux include: Carriers, activators, surfactants, thixotropic agents and corrosion inhibitors.

2. The environmentally friendly ultra-fine solder wire according to claim 1, characterized in that: The outer film layer is made by mixing zinc compound and phenolic resin in a proportion of 2:1 to 1:

1.

3. The environmentally friendly ultra-fine solder wire according to claim 1, characterized in that: The outer film layer is made by mixing zinc compound and polyurethane in a proportion of 2:1 to 1:

1.

4. The environmentally friendly ultra-fine solder wire according to claim 1, characterized in that: The weight proportion of each component in the third element alloy is: Tin (Sn) accounts for 54.0% to 64.5%, bismuth (Bi) accounts for 29.7% to 39.8%, and element alloy accounts for 2.3% to 3.7%, with a total proportion of 100%.

5. The environmentally friendly ultra-fine solder wire according to claim 4, characterized in that: The weight of each component in the elemental alloy accounts for the total weight of the tin wire: Gallium Ga accounts for 0.05% to 0.1wt%, indium In accounts for 0.15% to 0.33wt%, cobalt Co accounts for 0.15% to 0.24wt%, and nickel Ni accounts for 1.7% to 3.32wt%.

6. The environmentally friendly ultra-fine solder wire according to claim 1, characterized in that: The weight proportion of each component in the flux is: The carrier accounts for 65% to 80%, the activator accounts for 6% to 15%, the surfactant accounts for 5% to 16%, the thixotropic agent accounts for 1% to 2.85%, the corrosion inhibitor accounts for 0.46% to 6.32%, and the total proportion is 100%.

7. The environmentally friendly ultra-fine solder wire according to claim 1, characterized in that: The carrier in the flux is a mixture of esterified rosin, graphene dispersion and propylene glycol.

8. The environmentally friendly ultra-fine solder wire according to claim 7, characterized in that: The weight percentages of the components in the carrier in the flux are: The esterified rosin accounts for 55% to 72%, the graphene dispersion accounts for 0.5% to 10%, and the propylene glycol accounts for 1% to 5%.

9. The environmentally friendly ultra-fine solder wire according to claim 1, characterized in that: The corrosion inhibitor in the soldering flux is one of methylbenzotriazole and OP-10 or a mixture of the two. The weight percentages of the components of the corrosion inhibitor in the soldering flux are as follows: Tolyltriazole 0% to 1.87%, OP-10 0% to 5%.

10. A method for preparing an environmentally friendly ultra-fine solder wire, applied to the environmentally friendly ultra-fine solder wire according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Raw material preparation and smelting: weigh tin Sn, bismuth Bi and elemental alloy raw materials according to weight ratio, melt and heat these raw materials to 380-400°C, perform heat preservation, stirring, standing and slag removal, and then cast a cylindrical billet with a specification of Φ84×180mm; Step 2: Coarse wire extrusion, put the Φ84×180mm rod blank into a 350-ton large deformation extruder with a wire outlet diameter of Φ9mm, and at the same time add rosin welding oil into the rosin barrel at a ratio of 2.0% to 2.6%, control the rosin barrel temperature at 110℃, the rod blank temperature at 100℃, and the extrusion pressure at 150kg / cm 2 , the wire speed is about 1.5m / min, adjust the centering and gap size of the rosin nozzle, and test the flux content of the thick wire until the flux content of the core of the thick tin wire reaches 2.0% to 2.6%; Step 3: Rolling forming: insert the Φ9mm thick tin wire into the 16-pass near-final forming roller mill to roll out the Φ3.0mm solder wire; Step 4: Fine drawing and coating. The Φ3.0mm near-final finished solder wire with a nearly circular cross section is sequentially passed through three wire drawing machines with 28 diamond drawing dies for drawing. The first wire drawing machine draws the solder wire to Φ0.8mm, the second wire drawing machine draws the solder wire to Φ0.3mm, and the third wire drawing machine draws the solder wire into the final finished solder wire size of Φ0.10mm. After the solder wire completely passes through the second wire drawing machine, the coating process is carried out. The solder wire quickly passes through a film-forming molten liquid composed of zinc compounds and phenolic resin or polyurethane (the solution temperature is between 45 and 55°C), and the surface of the solder wire is cooled to form a film. Step 5: Brightening and anti-oxidation treatment: the coated solder wire is passed through a water tank with a cleaning tank for brightening and anti-oxidation treatment. The cleaning agent is 5% to 10% ST-010 saponification liquid, and the anti-oxidation coating agent is 2% to 5% dodecyl hydroxystearic acid alcohol solution; Step 6: Subsequent processing: the drawn ultra-fine solder wire is dried in the shade, wound, packaged and stored.

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