Soldering flux in use for SnZn series solder with no lead, and preparation method

A lead-free solder and flux technology, used in welding equipment, welding media, manufacturing tools, etc., can solve the problems of poor wettability, difficult brazing, and difficult to be widely used, and achieve good formability and bright solder joints. Effect

Inactive Publication Date: 2007-07-25
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose and task of the present invention are to overcome the poor wettability of the SnZn series lead-free solder in the prior art, the difficulty of brazing, and the deficiencies that are difficult to be widely used, and provide a method that can greatly improve the wettability of the SnZn series solder. A kind of SnZn series lead-free solder flux for SnZn solder and Cu solder joint bonding force and preparation method thereof, especially propose the technical solution of the present invention

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] An electronics factory uses reflow soldering process to produce double-sided assembly SMD, using SnZn solder for production, using common commercial flux, and the solder spreading rate cannot meet the requirements. Utilize the SnZn series lead-free solder flux that the present invention develops, obtained the wetting effect that spreading rate reaches 75%, obtained qualified product, and the flux proportioning composition of its application is:

[0028] BiCl 3 0.05%

[0029] Natural Rosin 60%

[0030] FSN 1%

[0031] Benzotriazole 0.01%

[0032] Absolute Ethanol 38.94%

[0033] Preparation method: in the first step, according to its weight percentage, its BiCl 3 , rosin, FSN, and benzotriazole are weighed and put into a beaker; the second step is to add the solvent absolute ethanol in proportion to the beaker, seal it, and fully dissolve the solid material at room temperature; The third step is to use a filter with a pore size of 1.5 μm to filter out impuri...

Embodiment 2

[0036] An electronics factory produces circuit boards of home appliances such as televisions and radios. In compliance with the requirements of lead-free, it uses lead-free solder wire instead, and has always used SnAgCu solder. Because the price of SnAgCu solder is too expensive, the cost of the product remains high, so I want to use SnZn, a low-cost lead-free solder, to replace it. Due to the poor wettability of SnZn solder wire, the pass rate of the product cannot be guaranteed with general-purpose RMA flux. The BiCl-containing product produced by the present invention is selected 3 After the SnZn series lead-free solder is used with flux, the brazing effect can reach the quality of using SnAgCu solder, and the product cost can be significantly reduced. The flux composition ratio used is as follows:

[0037] BiCl 3 6%

[0038] Natural Rosin 30%

[0039] FSN0.1%

[0040] Benzotriazole 2%

[0041] Absolute Ethanol 61.9%

[0042] Preparation method is with embod...

Embodiment 3

[0045] An electronics factory uses reflow soldering to produce computer motherboards, and has always used SnCu solder paste. Since the brazing temperature of SnCu brazing material exceeds 250°C, the circuit board is greatly damaged. Therefore, I want to use SnZn solder with low melting point and low price. However, due to the poor wettability of SnZn solder wire, general-purpose RMA flux cannot improve the wettability of SnZn solder to a satisfactory level. BiCl-containing 3 After the SnZn series lead-free solder is used with flux, the brazing effect can reach the quality of SnAgCu solder brazing, and the production cost is reduced. The flux selected for this product has a composition ratio of:

[0046] BiCl 3 0.5%

[0047] Natural Rosin 45%

[0048] FSN 0.8%

[0049] Benzotriazole 1.5%

[0050] Absolute Ethanol 52.2%

[0051] Preparation method is with embodiment 1.

[0052] When in use, it can be implemented by using a general-purpose wave soldering machin...

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PUM

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Abstract

A flux for improving the wetting and spreading performane of lead-free SnZn solder is proportionally prepared from rosin, surfactant FSN, benzotriazazole and absolute alcohole through proportionally dissolving said components in absolute alcohol in sealed state, and filtering.

Description

technical field [0001] The invention relates to a flux, which is suitable for soldering of SnZn-based lead-free solder in the field of electronic packaging, and is especially suitable for manufacturing solder cores of SnZn-based solder wires and fluxes for wave soldering of SnZn-based solder. technical background [0002] The application of traditional tin-lead (SnPb) solder has a history of thousands of years and is currently the main material for electronic packaging and interconnection. However, lead and its compounds are toxic substances, which bring great harm to the living environment and safety of human beings. Since the U.S. anti-lead bill HR25374 (U.S. Congress), S22637 and S2391 (U.S. Senate) were proposed, various organizations, scientific research institutions and companies around the world have launched a series of prohibition proposals, test evaluations and environmental protection products. On February 13, 2003, the European Union promulgated the "Waste Elect...

Claims

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Application Information

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IPC IPC(8): B23K35/362
Inventor 马海涛王来马洪列黄明亮赵杰
Owner DALIAN UNIV OF TECH
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