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Low melting point lead-free solder alloy

A technology of lead-free solder alloy and low melting point, which is applied in the field of lead-free solder alloy and can solve problems such as poor reliability of solder joints

Inactive Publication Date: 2009-03-25
GUANGZHOU RES INST OF NON FERROUS METALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the solder alloy is solidifying, due to the phenomenon of "cold expansion" of a large amount of Bi elements segregated at the grain boundary, causing deformation and peeling off the solder joint and the pad, resulting in poor reliability of the solder joint

Method used

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Embodiment Construction

[0011] In the preparation process of the alloy of the present invention, since the differences in melting points of Sn, Cu, RE, and Ni increase, and RE is easy to burn out, in order to accurately control the alloy composition and ensure the quality of the alloy, various alloys are added in the form of master alloys elements, prepared as follows:

[0012] Sn-Cu master alloy: Add 99.95% refined Sn into the graphite crucible, heat up after melting, and add 99.95% pure Cu to an appropriate temperature range. The mass percentage of refined Sn and pure Cu is prepared at a ratio of 90:10, stirred evenly, left standing, and cast into a Sn-Cu master alloy ingot with a Cu content of 10%.

[0013] Sn-RE master alloy: Add 99.95% refined Sn into the graphite crucible, heat up after melting, and add high-purity RE to an appropriate temperature range. The mass percentage of refined Sn and RE is prepared as 97:3, stirred evenly, left standing, and casted into a Sn-RE master alloy ingot with ...

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PUM

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Abstract

The invention discloses a lead-free solder alloy with a low melting point, which is composed of the following components: 53.0wt percent to 65.0wt percent of Bi, 0.02wt percent to 0.5wt percent of Cu, 0.01wt percent to 0.43wt percent of Ag, 0.01wt percent to 0.4wt percent of Ni, 0.001wt percent to 0.6wt percent of RE, and Sn as the rest. The invention is the lead-free solder alloy of a low melting point that can improve brittleness, enhance tractility and plasticity, be easy to be manufactured into thread-solder and have high reliability of welding spots. The lead-free solder alloy with a low melting point is applied to the welding of heat sensitive components and parts and the step soldering of electronic components and parts.

Description

technical field [0001] The invention relates to a lead-free solder alloy with a low melting point, in particular to a lead-free solder alloy with a low melting point. Background technique [0002] In the electronics industry, low-temperature solder is widely used in the welding of heat-sensitive components in the electronics industry, as well as the graded brazing (secondary welding) of electronic components, and is also used in TV tuners, fire alarms, temperature control components, air conditioners In industries such as safety protectors. [0003] The traditional low-temperature solder is a ternary or quaternary alloy composed of Sn, Pb, Bi, Cd and other metals, among which Pb and Cd are harmful metal elements. With the development of science and the progress of society, clear requirements and indicators have been put forward for the environmental protection performance of electronic products. In the electronic market, electronic components that have not passed environmen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C12/00
Inventor 张宇航赵四勇戴贤斌蔡志红韩振峰
Owner GUANGZHOU RES INST OF NON FERROUS METALS
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