Lead-free solder

Abstract

The invention relates to a leadless tin soldering material which comprises the constituents (by mass ratio) of Ag 0.5-6%, Cu 0.1-2%, In 0.0001-1%, P 0.0001-1%, and balancing Sn. The preparing process of the soldering material comprises weighing 1.67-20 parts of Sn-Ag intermediate alloy ingot containing Ag 30%, 1-20 parts of Sn-Cu intermediate alloy ingot containing Cu 30%, 0.002-20 parts of Sn-In intermediate alloy ingot containing In 5%, P 0.0001-1 part, and balancing Sn in the whole 100 parts, charging the raw materials into manganese alloy crucible, smelting in intermediate frequency furnaces, evacuating and filling in nitrogen, elevating the temperature to 450 deg. C, agitating 1 hour, cooling down slowly and homogeneously to 340 deg C, charging weighed P and stirring homogeneously, finally pouring the melted liquid into dies.

Description

technical field

[0001] The invention relates to soldering materials, in particular to a lead-free tin solder, which belongs to the field of tin alloys. Background technique

[0002] With the rapid development of the electronics industry, the requirements for electronic products are getting higher and higher. There are many types of solder used in current electronic products, but most of them still use tin-lead alloy solder. Because the lead in tin-lead solder pollutes the environment, Harmful to people, so many countries began to ban the use of leaded solder. Most of the existing lead-free solders are tin-silver, tin-copper, tin-silver-copper, tin-zinc-indium-bismuth, and tin-silver alloys. Sex is small, and some cost is high. Contents of the invention

[0003] The purpose of the present invention is to overcome the shortcomings and deficiencies of the above-mentioned prior art, and provide a lead-free solder with low melting point, good wettability and low cost, thereby...