Sn-Zn-Cr alloy lead-free solder preparation method

A technology of lead-free solder and alloy, which is applied in the preparation field of soldering technology. It can solve the problems that it is difficult to obtain an alloy with uniform composition, it is difficult to completely melt, and it cannot be used. It achieves low melting point, uniform metallographic structure, and improved ductility. Effect

Inactive Publication Date: 2006-02-08
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since Cr is a metal with a high melting point and is smelted at 800°C, it is difficult to completely melt even if Cr powder is used, and it is difficult to obtain an alloy with a uniform composition.
However, when the Cr powder is too fine, it is very easy to oxidize, and it has been oxidized in large quantities before smelting, and the purity is very poor.
Therefore, this method can only be used for research purposes and cannot be used in actual industrial production.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] The composition and mass percentage of the material of the present invention are as follows: Cr is 0.005%, Zn is 3%, and the balance is Sn.

[0018] (1) Preparation of master alloy Sn-Cr

[0019] ①According to the composition requirements of the Sn-Zn-Cr alloy solder with Cr being 0.005%, Zn being 3%, and the balance being Sn, first weigh the bulk, granular or powdered pure metal Cr and Sn respectively, and at room temperature, All of the Cr raw material and the Sn raw material having the same weight as the Cr raw material were thoroughly mixed.

[0020] ②Under the hydrogen protective atmosphere, raise the temperature above the melting point of metal Cr, that is, control it within the range of 1857°C, keep it warm for 30 minutes after melting, and stir thoroughly. This method adopts smelting under protective atmosphere conditions such as vacuum or argon, and its purpose is to more effectively prevent the oxidation and burning of metals during the smelting process.

[...

Embodiment 2

[0028] The composition and mass percentage of the material of the present invention are as follows: Cr is 0.75%, Zn is 9%, and the balance is Sn.

[0029] (1) Preparation of master alloy Sn-Cr

[0030] ①According to the composition requirements of the Sn-Zn-Cr alloy solder with Cr being 0.75%, Zn being 9%, and the balance being Sn, first weigh bulk, granular or powdered pure metal Cr and Sn respectively, and at room temperature, All of the Cr raw material and the Sn raw material having the same weight as the Cr raw material were thoroughly mixed.

[0031] ②Under the protective atmosphere of argon, raise the temperature above the melting point of metal Cr, that is, control it within the range of 2100°C, keep it warm for 30 minutes after melting, and stir thoroughly. This method adopts smelting under protective atmosphere conditions such as vacuum or argon, and its purpose is to more effectively prevent the oxidation and burning of metals during the smelting process.

[0032] ...

Embodiment 3

[0039] The composition and mass percentage of the material of the present invention are as follows: Cr is 1.5%, Zn is 12%, and the balance is Sn.

[0040] (1) Preparation of master alloy Sn-Cr

[0041] ①According to the composition requirements of the Sn-Zn-Cr alloy solder with Cr being 1.5%, Zn being 12%, and the balance being Sn, first weigh bulk, granular or powdered pure metal Cr and Sn respectively, and at room temperature, All of the Cr raw material and the Sn raw material having the same weight as the Cr raw material were thoroughly mixed.

[0042] ②Under vacuum conditions, raise the temperature above the melting point of metal Cr, that is, control it within the range of 1957°C, keep it warm for 30 minutes after melting, and stir thoroughly. This method adopts smelting under protective atmosphere conditions such as vacuum or argon, and its purpose is to more effectively prevent the oxidation and burning of metals during the smelting process.

[0043] ③Put the remaining ...

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Abstract

Disclosed is a Sn-Zn-Cr alloy lead-free solder preparation method which comprises, (1) preparation of Sn-Cr intermediate alloy, which consists of mixing Cr 0.005-1.5%, Zn 3-12%, and balancing Sn, elevating temperature to above the fusion point of the metal Cr, melting and thermally insulating, fully stirring, charging the residue Sn raw material into the furnace, waiting for dissolution, cooling down, thermally insulating, continuing stirring simultaneously, (2) smelting of Sn-Zn-Cr alloy, which consists of charging the Zn raw material into melting Sn-Cr intermediate alloy, waiting for complete dissolution, fully stirring, thermally insulating, cooling down, thermally insulating while agitating continuously, finally cooling down to room temperature or casting as requirement.

Description

technical field [0001] The invention relates to a preparation method in the technical field of soldering, in particular to a preparation method of Sn-Zn-Cr alloy lead-free solder. Background technique [0002] At present, the lead-free solders that can be used mainly include Sn-Ag series and Sn-Zn series or ternary or quaternary alloy solders derived from these two alloys, such as Sn-Ag-Cu, Sn-Zn -Bi et al. However, compared with the traditional lead-containing Sn-Pb solder, the melting point of Sn-Ag solder is nearly 40°C higher, the price is doubled, and it has poor compatibility with existing equipment and processes, and there are many shortcomings that are difficult to overcome. . Compared with this, Sn-Zn lead-free solder has attracted much attention due to its melting point close to that of Sn-Pb solder, compatibility with existing processes and equipment, high strength, abundant resources, and low price. The Zn element in this type of solder has a high reactivity a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C13/00C22C1/03C22C1/06
Inventor 李明任晓雪陈熹毛大立
Owner SHANGHAI JIAO TONG UNIV
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