An environment-friendly lead-free solder bar for welding electronic components and its production process

Abstract

The present invention discloses an environment-friendly lead-free solder bar for welding electronic components and its production process, which relates to the technical field of welding materials and is made of the following components by weight percentage: Ag 0.08 - 0.13wt%, Cu 0.1 - 0.6wt%, Zn 0.12 - 0.32wt%, Te 0.01 - 0.03wt%, rare earth 0.01 - 0.1wt%, In 0.003 - 0.01wt%, Ba 0.005 - 0.013wt%, Bi 0.2 - 1wt%, Sb 0.01 - 0.03wt%, Se 0.001 - 0.02wt%, Ge 0.008 - 0.015wt%, and the balance is Sn. The solder bar has good wettability and fluidity after melting, and high cost performance, solder joint strength and solder joint reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of welding materials, and particularly to an environment-friendly lead-free solder bar for welding electronic components and its production process. Background Art

[0002] In recent years, with the increasingly rapid development of electronic products and the enhancement of human environmental protection awareness, the traditional Sn-Pb solder bars used in the electronics industry have gradually been replaced by lead-free solder bars. Lead-free solder bars have good thermal conductivity and plasticity, and better environmental protection, and can be used to connect electronic components, circuit boards and other metal parts. At present, lead-free solder bars have been widely used in fields such as electronic manufacturing, electrical engineering, metal processing and maintenance.

[0003] The existing lead-free solder bars used for welding electronic components more or less have technical defects such as the solder joint strength and solder joint reliability needing to be further improved, serious solder joint oxidation corrosion and pinhole phenomena, and the wettability and fluidity needing to be further improved. To solve the above problems, a Chinese invention patent with the application publication number CN118046134A discloses a lead-free solder bar and its manufacturing process. The lead-free solder bar includes the following components in parts by weight: 94-95 parts of elemental Sn powder, 2.8-3.3 parts of elemental Ag powder, 2-3 parts of elemental Cu powder, 0.02-0.06 parts of elemental Co powder, and 0.01-0.04 parts of strengthening auxiliary agent. This invention uses elemental Co powder, Ni powder or W powder as additives, and elemental La powder or elemental Nd powder as strengthening auxiliary agents, significantly improving the tensile strength and elongation rate of the solder bar. The tensile strength reaches 1965.3-2452.0 MPa. The elongation rate reaches 10.8-16.1%. It enables the solder bar to be better applied in connecting electronic components, circuit boards and other metal parts, etc., and expands its practical applications in fields such as electronic manufacturing, electrical engineering, metal processing and maintenance. However, this lead-free solder bar still has technical problems such as the wettability and fluidity needing to be further improved, and the cost performance, solder joint strength and solder joint reliability needing to be further improved.

[0004] It can be seen that it is necessary to seek a more effective production process to prepare an environment-friendly lead-free solder bar for welding electronic components with good wettability and fluidity after melting, high cost performance, solder joint strength and solder joint reliability. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an environment-friendly lead-free solder bar for welding electronic components with good wettability and fluidity after melting, high cost performance, solder joint strength and solder joint reliability and its production process.

[0006] To achieve the above object, the technical solution adopted by the present invention is: an environment-friendly lead-free solder bar for electronic component soldering, which is made of the following components by weight percentage: Ag 0.08 - 0.13wt%, Cu 0.1 - 0.6wt%, Zn 0.12 - 0.32wt%, Te 0.01 - 0.03wt%, rare earth 0.01 - 0.1wt%, In 0.003 - 0.01wt%, Ba 0.005 - 0.013wt%, Bi 0.2 - 1wt%, Sb 0.01 - 0.03wt%, Se 0.001 - 0.02wt%, Ge 0.008 - 0.015wt%, and the balance is Sn.

[0007] Preferably, the environment-friendly lead-free solder bar for electronic component soldering is made of the following components by weight percentage: Ag 0.1wt%, Cu 0.3wt%, Zn 0.22wt%, Te 0.02wt%, rare earth 0.05wt%, In 0.006wt%, Ba 0.01wt%, Bi 0.6wt%, Sb 0.02wt%, Se 0.01wt%, Ge 0.011wt%, and the balance is Sn.

[0008] Preferably, the rare earth is at least one of La, Pr, and Ce.

[0009] Another object of the present invention is to provide a production process for the environment-friendly lead-free solder bar for electronic component soldering, which includes the following steps:

[0010] Step S1: Using metallic tin, Ag-Sn alloy intermediate, Cu-Sn alloy intermediate, Zn-Sn alloy intermediate, Te-Sn alloy intermediate, rare earth-Sn alloy intermediate, In-Sn alloy intermediate, Ba-Sn alloy intermediate, Bi-Sn alloy intermediate, Sb-Sn alloy intermediate, Se-Sn alloy intermediate, Ge-Sn alloy intermediate as raw materials, proportioning according to the component weight percentage, grinding and sieving to obtain a raw material mixture;

[0011] Step S2: Putting the raw material mixture prepared in Step S1 into a melting furnace to melt evenly;

[0012] Step S3: Pouring and molding the melted alloy to obtain an environment-friendly lead-free solder bar for electronic component soldering.

[0013] Preferably, the grinding and sieving in Step S1 is grinding and sieving through a 200 - 400 mesh sieve.

[0014] Preferably, the melting in Step S2 is carried out under vacuum.

[0015] Preferably, the pouring and molding in Step S2 is carried out under the protection of inert gas.

[0016] Preferably, the inert gas is any one of nitrogen, helium, neon, and argon.

[0017] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0018] (1) The production process of the environment-friendly lead-free solder bar for electronic component welding disclosed by the present invention is simple and easy to implement, with high production efficiency and finished product qualification rate, low dependence on equipment, suitable for continuous large-scale production, and has high popularization and application value.

[0019] (2) The environment-friendly lead-free solder bar for electronic component welding disclosed by the present invention is made of the following components by weight percentage: Ag 0.08 - 0.13wt%, Cu 0.1 - 0.6wt%, Zn 0.12 - 0.32wt%, Te 0.01 - 0.03wt%, rare earth 0.01 - 0.1wt%, In 0.003 - 0.01wt%, Ba 0.005 - 0.013wt%, Bi 0.2 - 1wt%, Sb 0.01 - 0.03wt%, Se 0.001 - 0.02wt%, Ge 0.008 - 0.015wt%, and the balance is Sn. Through the mutual cooperation and joint action of each component, it can effectively reduce the surface tension of the molten solder, improve the solderability, reduce the oxygen content, make the alloy structure compact, reduce solder joint pinholes and slow down the oxidation and corrosion of solder joints, and improve the welding strength and reliability; endow the made environment-friendly lead-free solder bar with good wettability and fluidity after melting, and the advantages of high cost performance, solder joint strength and solder joint reliability.

[0020] (3) The environment-friendly lead-free solder bar for electronic component welding disclosed by the present invention, through the reasonable selection of the component formula, enables each component to play a better interaction with each other, effectively eliminates solder joint bridging, inhibits the oxidation of the alloy, and improves the antioxidant ability; it can be used for a long time in the molten state, has good fluidity and wettability, while extending the service time, it is not easy to turn yellow, not easy to turn blue, and can effectively reduce the generation of tin dross.

[0021] (4) The environment-friendly lead-free solder bar for electronic component welding disclosed by the present invention does not contain lead, is safer and more environmentally friendly to use, and meets the environmental protection requirements of lead-free. And it has good welding performance, good solder joint strength and reliability, and is suitable for the welding of electronic components. Specific Embodiments

[0022] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations.

[0023] Example 1

[0024] An environment-friendly lead-free solder bar for welding electronic components, which is made of the following components by weight percentage: Ag 0.08wt%, Cu 0.1wt%, Zn 0.12wt%, Te 0.01wt%, rare earth 0.01wt%, In 0.003wt%, Ba 0.005wt%, Bi 0.2wt%, Sb 0.01wt%, Se 0.001wt%, Ge 0.008wt%, and the balance is Sn; the rare earth is La.

[0025] A production process of the environment-friendly lead-free solder bar for welding electronic components, which comprises the following steps:

[0026] Step S1: Using metallic tin, Ag-Sn alloy intermediate, Cu-Sn alloy intermediate, Zn-Sn alloy intermediate, Te-Sn alloy intermediate, rare earth-Sn alloy intermediate, In-Sn alloy intermediate, Ba-Sn alloy intermediate, Bi-Sn alloy intermediate, Sb-Sn alloy intermediate, Se-Sn alloy intermediate, Ge-Sn alloy intermediate as raw materials, proportioning according to the component weight percentage, grinding and sieving to obtain a raw material mixture;

[0027] Step S2: Putting the raw material mixture prepared in step S1 into a melting furnace to melt evenly;

[0028] Step S3: Pouring and molding the melted alloy to obtain an environment-friendly lead-free solder bar for welding electronic components.

[0029] The grinding and sieving in step S1 is grinding through a 200-mesh sieve; the melting in step S2 is carried out under vacuum; the pouring and molding in step S2 is carried out under the protection of an inert gas; the inert gas is nitrogen.

[0030] Example 2

[0031] An environment-friendly lead-free solder bar for welding electronic components, which is made of the following components by weight percentage: Ag 0.09wt%, Cu 0.2wt%, Zn 0.18wt%, Te 0.015wt%, rare earth 0.04wt%, In 0.006wt%, Ba 0.008wt%, Bi 0.5wt%, Sb 0.015wt%, Se 0.008wt%, Ge 0.011wt%, and the balance is Sn; the rare earth is Pr.

[0032] A production process of the environment-friendly lead-free solder bar for welding electronic components, which comprises the following steps:

[0033] Step S1: Using metallic tin, Ag-Sn alloy intermediate, Cu-Sn alloy intermediate, Zn-Sn alloy intermediate, Te-Sn alloy intermediate, rare earth-Sn alloy intermediate, In-Sn alloy intermediate, Ba-Sn alloy intermediate, Bi-Sn alloy intermediate, Sb-Sn alloy intermediate, Se-Sn alloy intermediate, Ge-Sn alloy intermediate as raw materials, proportioning according to the weight percentage of components, grinding and sieving to obtain a raw material mixture;

[0034] Step S2: Putting the raw material mixture prepared in Step S1 into a melting furnace to melt evenly;

[0035] Step S3: Pouring and molding the melted alloy to obtain an environment-friendly lead-free solder bar for electronic component welding.

[0036] The grinding and sieving in Step S1 is grinding through a 250-mesh sieve; the melting in Step S2 is carried out under vacuum; the pouring and molding in Step S2 is carried out under the protection of inert gas; the inert gas is helium.

[0037] Example 3

[0038] An environment-friendly lead-free solder bar for electronic component welding, which is made of the following components by weight percentage: Ag 0.1wt%, Cu 0.3wt%, Zn 0.22wt%, Te 0.02wt%, rare earth 0.05wt%, In 0.006wt%, Ba 0.01wt%, Bi 0.6wt%, Sb 0.02wt%, Se 0.01wt%, Ge 0.011wt%, and the balance is Sn; the rare earth is Ce.

[0039] A production process of the environment-friendly lead-free solder bar for electronic component welding, which includes the following steps:

[0040] Step S1: Using metallic tin, Ag-Sn alloy intermediate, Cu-Sn alloy intermediate, Zn-Sn alloy intermediate, Te-Sn alloy intermediate, rare earth-Sn alloy intermediate, In-Sn alloy intermediate, Ba-Sn alloy intermediate, Bi-Sn alloy intermediate, Sb-Sn alloy intermediate, Se-Sn alloy intermediate, Ge-Sn alloy intermediate as raw materials, proportioning according to the weight percentage of components, grinding and sieving to obtain a raw material mixture;

[0041] Step S2: Putting the raw material mixture prepared in Step S1 into a melting furnace to melt evenly;

[0042] Step S3: Pouring and molding the melted alloy to obtain an environment-friendly lead-free solder bar for electronic component welding.

[0043] In Step S1, the grinding and sieving is to grind and sieve through a 300-mesh sieve; in Step S2, the melting is carried out under vacuum; in Step S2, the casting and molding is carried out under the protection of an inert gas; the inert gas is neon.

[0044] Example 4

[0045] An environment-friendly lead-free solder bar for welding electronic components is made of the following components by weight percentage: Ag 0.12 wt%, Cu 0.5 wt%, Zn 0.3 wt%, Te 0.025 wt%, rare earth 0.09 wt%, In 0.008 wt%, Ba 0.012 wt%, Bi 0.9 wt%, Sb 0.025 wt%, Se 0.013 wt%, Ge 0.012 wt%, and the balance is Sn; the rare earth is a mixture of La, Pr, and Ce in a mass ratio of 1:2:3.

[0046] A production process of the environment-friendly lead-free solder bar for welding electronic components includes the following steps:

[0047] Step S1: Using metallic tin, Ag-Sn alloy intermediate, Cu-Sn alloy intermediate, Zn-Sn alloy intermediate, Te-Sn alloy intermediate, rare earth-Sn alloy intermediate, In-Sn alloy intermediate, Ba-Sn alloy intermediate, Bi-Sn alloy intermediate, Sb-Sn alloy intermediate, Se-Sn alloy intermediate, and Ge-Sn alloy intermediate as raw materials, proportioning according to the component weight percentage, grinding and sieving to obtain a raw material mixture;

[0048] Step S2: Putting the raw material mixture prepared in Step S1 into a melting furnace and melting it evenly;

[0049] Step S3: Casting and molding the melted alloy to obtain an environment-friendly lead-free solder bar for welding electronic components.

[0050] In Step S1, the grinding and sieving is to grind and sieve through a 350-mesh sieve; in Step S2, the melting is carried out under vacuum; in Step S2, the casting and molding is carried out under the protection of an inert gas; the inert gas is argon.

[0051] Example 5

[0052] An environment-friendly lead-free solder bar for welding electronic components is made of the following components by weight percentage: Ag 0.13 wt%, Cu 0.6 wt%, Zn 0.32 wt%, Te 0.03 wt%, rare earth 0.1 wt%, In 0.01 wt%, Ba 0.013 wt%, Bi 1 wt%, Sb 0.03 wt%, Se 0.02 wt%, Ge 0.015 wt%, and the balance is Sn; the rare earth is La.

[0053] A production process of an environmentally friendly lead-free solder bar for welding electronic components, comprising the following steps:

[0054] Step S1: Using metallic tin, Ag-Sn alloy intermediate, Cu-Sn alloy intermediate, Zn-Sn alloy intermediate, Te-Sn alloy intermediate, rare earth-Sn alloy intermediate, In-Sn alloy intermediate, Ba-Sn alloy intermediate, Bi-Sn alloy intermediate, Sb-Sn alloy intermediate, Se-Sn alloy intermediate, Ge-Sn alloy intermediate as raw materials, proportioning according to the component weight percentage, grinding and sieving to obtain a raw material mixture;

[0055] Step S2: Putting the raw material mixture prepared in Step S1 into a melting furnace and melting it evenly;

[0056] Step S3: Pouring and molding the melted alloy to obtain an environmentally friendly lead-free solder bar for welding electronic components.

[0057] The grinding and sieving in Step S1 is grinding through a 400-mesh sieve; the melting in Step S2 is carried out under vacuum; the pouring and molding in Step S2 is carried out under the protection of an inert gas; the inert gas is nitrogen.

[0058] Comparative Example 1

[0059] An environmentally friendly lead-free solder bar for welding electronic components and its production process are basically the same as those in Example 1, except that Te and Ge are not added.

[0060] Comparative Example 2

[0061] An environmentally friendly lead-free solder bar for welding electronic components and its production process are basically the same as those in Example 1, except that In and Ba are not added.

[0062] In order to further illustrate the beneficial technical effects of the environmentally friendly lead-free solder bars for welding electronic components involved in each embodiment of the present invention, relevant performance tests are carried out on the environmentally friendly lead-free solder bars for welding electronic components involved in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1, and the test methods are as follows:

[0063] (1) Fluidity and wettability: For the environmentally friendly lead-free solder bar in the molten state, use a small tin furnace to test the time to maintain a mirror surface. The longer the time to maintain the mirror surface, the better the fluidity and wettability of the solder bar after melting.

[0064] (2) Tensile strength and elongation rate test: The tensile strength and elongation rate tests are carried out on a Shimadzu precision electronic material universal testing machine (CMT4305). The tensile speed is 0.5 mm / s, the sample thickness is 1.0 mm, the width is 3.2 mm, the parallel length is 10 mm, the gauge length is 5 mm, and the strain rate is 10-3 s -1 For each sample, conduct the test 5 times and take the average value.

[0065] (3) Void ratio test: Use reflow soldering and adopt the X-ray detection method to conduct the void ratio test, where the void ratio = (S1 - S2) / S1. In the formula, S1 is the solderable area of the chip, and S2 is the actual soldered area of the chip.

[0066] Table 1

[0067]

[0068] As can be seen from Table 1, the environment-friendly lead-free solder bar for electronic component soldering involved in the embodiments of the present invention has more excellent tensile strength and elongation rate than the products of the comparative examples, lower void ratio, better wettability and fluidity after melting, and the addition of Te, Ge, In, and Ba is beneficial to improving the above properties.

[0069] The above embodiments are only used to illustrate the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. An environmentally friendly lead-free solder bar for welding electronic components, characterized in that: The invention comprises the following components in weight percentage: Ag 0.08-0.13wt%, Cu 0.1-0.6wt%, Zn 0.12-0.32wt%, Te 0.01-0.03wt%, rare earth 0.01-0.1wt%, In 0.003-0.01wt%, Ba 0.005-0.013wt%, Bi 0.2-1wt%, Sb 0.01-0.03wt%, Se 0.001-0.02wt%, Ge 0.008-0.015wt%, and the balance is Sn.

2. The environmentally friendly lead-free solder bar for welding electronic components according to claim 1, characterized in that: The environmentally friendly lead-free solder bar for welding electronic components comprises the following components in percentage by weight: 0.1wt% Ag, 0.3wt% Cu, 0.22wt% Zn, 0.02wt% Te, 0.05wt% rare earth, 0.006wt% In, 0.01wt% Ba, 0.6wt% Bi, 0.02wt% Sb, 0.01wt% Se, 0.011wt% Ge, and the balance is Sn.

3. The environmentally friendly lead-free solder bar for welding electronic components according to claim 1, characterized in that: The rare earth is at least one of La, Pr and Ce.

4. A production process for environmentally friendly lead-free solder bars for welding electronic components according to any one of claims 1 to 3, characterized in that: The steps include: Step S1, using metallic tin, Ag-Sn alloy, Cu-Sn alloy, Zn-Sn alloy, Te-Sn alloy, rare earth-Sn alloy, In-Sn alloy, Ba-Sn alloy, Bi-Sn alloy, Sb-Sn alloy, Se-Sn alloy, Ge-Sn alloy as raw materials, mixing ingredients according to weight percentage of components, grinding and screening to obtain a raw material mixture; Step S2, placing the raw material mixture prepared in step S1 into a melting furnace and melting it evenly; Step S3: casting the molten alloy to obtain an environmentally friendly lead-free solder bar for welding electronic components.

5. The production process of environmentally friendly lead-free solder bars for welding electronic components according to claim 4, characterized in that: The grinding and screening in step S1 is grinding through a 200-400 mesh sieve.

6. The production process of environmentally friendly lead-free solder bars for welding electronic components according to claim 4, characterized in that: The melting in step S2 is performed under vacuum.

7. The production process of environmentally friendly lead-free solder bars for welding electronic components according to claim 4, characterized in that: The casting molding in step S2 is performed under the protection of an inert gas.

8. The production process of environmentally friendly lead-free solder bars for welding electronic components according to claim 7, characterized in that: The inert gas is any one of nitrogen, helium, neon and argon.

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