Tin-based lead-free solder and preparation method thereof

Abstract

The invention discloses a tin-based lead-free solder and a preparation method thereof. The tin-based lead-free solder comprises the following components in percentage by weight: 3.0 to 6.0% of Sb, 1.0 to 8.0% of In, 1.0 to 2.0% of Cu, 0.8 to 1.0% of Ni, 0.03 to 0.08% of La, 0.03 to 0.08% of Ce and the balance of tin, wherein the purities of In, La and Ce are 99.99%, and the other raw materials are industrial refined raw materials. The preparation method comprises the steps as follows: firstly, intermediate alloys of Sn-Sb, Sn-Cu, Sn-Ni, Sn-In, Sn-La and Sn-Ce are prepared by melting; and according to the weight percentage of all components, a proper amount of pure Sn and all intermediate alloys are weighed and placed in a stainless steel pot to be mixed and smelted at a heating temperature of 600 DEG C, a covering agent is added, and the mixture is stirred for half an hour and then is cast to obtain the tin-based lead-free solder. The tin-based lead-free solder has the characteristics of lower melting point, high metal plasticity, good wetting property and excellent spreadability.

Description

technical field [0001] The invention belongs to the field of new materials, and specifically relates to a tin-based lead-free solder and a preparation method thereof, which are applied to welding of electronic components, electrical appliances, telecommunications, instruments and other related products. Background technique [0002] In the field of soldering materials, Sn-Pb alloys are commonly used as electronic soldering materials, and tin-lead alloys have been widely used worldwide as high-quality and cheap soldering materials. However, with the strengthening of human environmental protection awareness, the harm of "lead" and its compounds to the human body And the pollution of the environment has been paid more and more attention by human beings. [0003] US Patent Publication No. US2004 / 0241039A1 discloses a lead-free solder, which contains more than 67% of Sn, 0.5-7.0% of Cu and 0.05-18% of Sb by mass percentage. This lead-free solder has a high melting point (above 2...

AI Technical Summary

Problems solved by technology

This lead-free solder has a high melting point (melting point above 230°C), which can adversely affect electrical products

The notice number is the lead-free solder of CN1252842A, which is composed of Ag: 1.0%-3.0%, antimony 0-4.0%, copper 0-2.0%, bismuth 10%-30%, and the balance is tin Sn. The melting point of this kind of lead-free solder is relatively low, but due to the high bismuth content, Sn-Bi is prone to dendrite segregation and structure coarsening during the solidification process, thereby affecting the mechanical properties of the solder and solder joints, and the solder joints are easy to peel off after soldering

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