Tin-zinc lead-free solder and preparation method thereof

A lead-free solder, zinc-based technology, applied in the direction of welding equipment, welding/cutting media/materials, welding media, etc., can solve the problem of lack of protection of the internal matrix, poor wettability, oxidation resistance, and poor corrosion resistance of solder etc. to achieve excellent wetting performance, improved wetting performance and low production cost

Inactive Publication Date: 2010-09-01
ZHUZHOU SMELTER GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, zinc in tin-zinc solder is an easily oxidizable element. When soldering in the air, the surface of the solder melt tends to form a loose ZnO layer, which floats on the surface of the melt, increasing the surface energy of the alloy surface and making the melt surface The tension is large, and the solder is difficult to wet with the substrate, resulting in poor wettability and oxidation resistance of the tin-zinc solder; Zno on the surface of the melt is easy to further generate Zn in a humid atmosphere or an environment containing sulfide or halide 5 (Co 3 ) 2 (OH) 6 ,, Zn 5 (OH) 8 Cl 2. h 2 O, ZnSO 4 .nH 2 O and other corrosion products, these products are easy to dissolve and be washed out, and cannot protect the internal matrix, resulting in poor corrosion resistance of the solder

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Prepare 500 grams of tin-zinc lead-free solder, its composition and content are the following weight percentages: Zn 7%; Ga 2%; the balance is Sn. Its production method is the following steps:

[0020] (1) Put Sn and Zn into the ceramic crucible in proportion using a crucible resistance furnace, and make 500 grams of Sn-Zn master alloy containing 5% Zn under the condition of 400° C., and the balance is Sn.

[0021] (2) 500 grams of Sn-Zn master alloy is put into a ceramic crucible and melted, and 333 grams of pure Zn are added after melting, and 18.5 grams of Ga (calculated by 10% burning loss) are added when the temperature is cooled to 200 ° C after complete melting, And stir constantly to homogenize the ingredients.

[0022] (3) Heat preservation, cooling, and casting into alloy.

[0023] The melting point of the obtained lead-free solder alloy is 193° C., and the soldering experiment of the Sn-Zn-Ga lead-free solder with a conventional electric soldering iron can ...

Embodiment 2

[0025] Prepare 500 grams of tin-zinc lead-free solder, the composition and content of which are the following weight percentages: Zn8%; Ga1%; the balance is Sn. Its production method is the following steps:

[0026] (1) Put Sn and Zn into the ceramic crucible in proportion using a crucible resistance furnace, and make 500 grams of Sn-Zn master alloy containing 7% Zn under the condition of 420° C., the balance being Sn.

[0027] (2) Put 500 grams of Sn-Zn master alloy into a ceramic crucible and melt, add 250 grams of pure Zn after melting, add 8.3 grams of Ga (calculated by 10% burning loss) when cooling to 220 ° C after complete melting, And stir constantly to homogenize the ingredients.

[0028] (3) Heat preservation, cooling, and casting into alloy.

[0029] The melting point of the obtained lead-free solder alloy is 193° C., and the soldering experiment of the Sn-Zn-Ga lead-free solder with a conventional electric soldering iron can be successfully tinned and soldered. ...

Embodiment 3

[0031] Prepare 500 grams of tin-zinc lead-free solder, the composition and content of which are the following weight percentages: Zn 7.5%; Ga 1.5%; the balance is Sn. Its production method is the following steps:

[0032] (1) Put Sn and Zn into the ceramic crucible in proportion using a crucible resistance furnace, and make 500 grams of Sn-Zn master alloy containing 9% Zn under the condition of 420° C., and the balance is Sn.

[0033] (2) Put 500 grams of Sn-Zn master alloy into a ceramic crucible and melt, add 100 grams of Sn after melting, add 10 grams of Ga (calculated by 10% burning loss) when cooling to 220 ° C after complete melting, and Stir constantly to homogenize the ingredients.

[0034] (3) Heat preservation, cooling, and casting into alloy.

[0035] The melting point of the obtained lead-free solder alloy is 193° C., and the soldering experiment of the Sn-Zn-Ga lead-free solder with a conventional electric soldering iron can be successfully tinned and soldered. ...

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Abstract

The invention relates to tin-zinc lead-free solder, which comprises the following components in percentage by weight: 7 to 9 percent of Zn, 0.1 to 2 percent of Ga and the balance of Sn. The tin-zinc lead-free solder is prepared by a two-step smelting method. The preparation method comprises the following steps of: (1) preparing tin and zinc into a Sn-Zn intermediate alloy in proportion at a smelting temperature of between 380 and 420 DEG C; (2) melting the Sn-Zn intermediate alloy, and after melting, adding the metal Ga when the temperature is reduced to between 180 and 220 DEG C; and (3) after the alloy is melted, continuously stirring the mixture to make the components uniform, and performing heat preservation, cooling and casting to form the alloy. The Sn-Zn-Ga lead-free solder alloy has low melting point and excellent combination property.

Description

technical field [0001] The invention relates to an electronic device welding and surface packaging material and a production method thereof, in particular to a tin-zinc lead-free solder and a production method thereof. Background technique [0002] Because the tin-lead solder traditionally used in the electronics industry contains the harmful substance lead, which pollutes the environment and damages the health of operators, with the enhancement of people's awareness of environmental protection, the formulation of European RoHS has gradually replaced it with lead-free environmentally friendly solder. [0003] At present, the lead-free solders used in the electronics industry mainly include Sn-Ag-Cu, Sn-Cu, Sn-Bi, and Sn-Zn systems, but compared with Sn-Pb eutectic solders, they all have obvious shortcomings. Table 1 below illustrates. [0004] Table 1 Advantages and disadvantages of various lead-free solders [0005] lead-free solder system mechanical ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/26B23K35/40
Inventor 潘向阳张伟窦传龙匡立春李正明张德晶
Owner ZHUZHOU SMELTER GRP
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