WO2007082459A1

WO2007082459A1 - Lead-free solder and its preparation method

Info

Publication number: WO2007082459A1
Application number: PCT/CN2007/000032
Authority: WO
Inventors: Shouyou Huang
Original assignee: Thousand Island Metal Foil Co., Ltd
Priority date: 2006-01-11
Filing date: 2007-01-08
Publication date: 2007-07-26
Also published as: CN1803380A

Abstract

The invention relates to a lead-free solder and a preparing method thereof. The solder comprises 0.1 -5.0 wt% Cu 0.001 -0.5 wt% Ni, 0.0001 -0.1 wt% P or Ga and a balance of Sn. According to the present invention, raw materials with high purity is used in the preparation of the solder, thus , the loss of metal is reduced, metallurgical structure is much more uniform, and the grain is refined. Also the wettability of the solder and the welding performance are improved. The present solder is preferred to be used in welding of wires or transformer.

Description

Lead-free solder and preparation method thereof

Technical field

The present invention relates to solder materials, and more particularly to a lead-free solder and a method of preparing the same.

Background technique

With the rapid development of the electronics industry, the demand for electronic products is getting higher and higher. There are many types of solders used in current electronic products, but most of them still use tin-lead alloy solder. Since lead-lead solder contains lead and pollute the environment, the EU issued two directives, which are banned from electronics on July 1, 2006. Lead-containing tin-lead solder is used in the product. Most of the existing lead-free solders are tin-silver, tin-copper, tin-silver-copper, tin-zinc-indium-germanium, tin-silver-mixed rare earth. The disadvantages of lead-free solder are that some have high melting points, some have low wettability, some have coarser crystals, and some have many complicated processes and high costs.

Summary of the invention

The object of the present invention is to provide a lead-free solder having a low melting point, good wettability and low cost in order to overcome the disadvantages and deficiencies of the prior art described above, thereby providing a high quality splicing material for processing and manufacturing electronic products. .

The object of the invention is achieved by the following technical solutions:

The lead-free solder of the present invention and a method for preparing the same, the composition of the solder is - Cu 0.1 - 5%, Ni 0.001 - 0.5%, P or Ga 0.001 - 0.1%, and Sn balance.

The composition weight percentage of lead-free solder is:

Cu 0.1-5%, Ni 0.001-0.5%, P.O.0001 - 0.1% and Sn balance.

Cu 0.1-5%, Ni 0.001-0.5%, Ga 0.0001-0.1% and Sn balance.

The preparation method of the lead-free solder adopts the following steps:

Preparation of intermediate alloy

1

Confirmation (a) Adding 99.95 % of tin containing tin to the graphite crucible, melting and heating to 1100 Ό, adding 99.95% of copper with copper, the ratio of copper to tin is 10:90, with wood The stirring rod is uniformly smelted into a liquid tin-copper alloy, and after standing for 30 minutes, it is cast into a tin-copper intermediate alloy ingot containing 10% of copper;

5: 97. The weight ratio of nickel to tin is 2. 5: 97. The weight ratio of nickel to tin is 2. 5: 97. 5, The tin-nickel intermediate alloy ingot containing nickel 2. 5 % was stirred for 30 minutes by stirring with a wooden stir bar.

(1) The amount of tin-copper intermediate alloy ingots in item (a) is 1 to 50 parts, the tin-nickel intermediate alloy ingots in (b) is 0. 4-6 parts, and the amount of insufficient tin is 18.6 - 98. 2 parts, added to the stainless steel pot for melting ^ After one hour of stirring, the alloy is produced, slowly and evenly cooled, until the temperature drops to 34 (TCrf added phosphorus or gallium, phosphorus or gallium added is 100-3000ppm _; '

(d) Pour the stirred solder into a mold and cast it into a lead-free solder bar to obtain the product of the present invention. - The present invention has the following advantages and effects as compared with the prior art:

1. The raw material used in the method has high purity and low metal loss during the process;

2. The metallurgy is more uniform and finer, which improves the wettability, elongation and welding performance;

3. This product has good welding performance for wire and transformer, and it is easy to produce good affinity with the substrate (solid material). The solder joint is bright, full and without welding phenomenon.

detailed description Example Lead-Free Solder Formula (% by Weight)

Manufacturing process

On the basis of the successful smelting of SnCu and SnNi intermediate alloys, the pure tin was melted and heated to 480 Ό to 520 Ό, and then the SnCu and SnNi intermediate alloys were melted and stirred for 15 minutes. Tin ingots or tin bars, solder bars, etc. required for extrusion.

Claims

Rights request

A lead-free solder and a method of preparing the same, characterized in that the composition percentage of the solder is: Cu 0.1-5%, Ni 0.001-0.5%, P or Ga 0.0001-0.1%, and Sn balance.

The lead-free solder according to claim 1, wherein the composition of the solder has a weight percentage of Cu 0.1-5%, Ni 0.001-0.5%, P 0.0001-0, 1 and Sn

3. The lead-free solder according to claim 1, wherein the composition of the solder is: CuO.1-5%, Ni 0.001-0.5%, Ga 0· 0001 - 0·1%. And Sn margin.

4. A method of preparing a lead-free solder according to claim 1 to 3, wherein the method comprises the steps of:

Preparation of intermediate alloy

(1) Add 99.95% tin of tin to the graphite clamp and melt it to a temperature of 1100. Add 99.95% copper to the copper. The weight ratio of copper to tin is 10:90. Stir with a wooden stir bar. Uniformly smelted into a liquid tin-copper alloy, and after standing for 30 minutes, cast a tin-copper intermediate alloy ingot containing 10% copper;

(2) 99.95% tin containing tin is added to the graphite crucible for melting. After heating to 1600 ° C and then adding 99.95% nickel, the weight ratio of nickel to tin is 2.5: 97.5, with wooden The stirring rod is uniformly smelted into a liquid tin-nickel alloy, and after standing for 30 minutes, it is cast into a tin-nickel intermediate alloy ingot containing 2.5% of nickel;

(3) Take 1 to 50 parts of the tin-copper intermediate alloy ingot of item (1), 0.4 to 6.0 parts of the tin-nickel intermediate alloy ingot of item (2), and 18.6-98.2 parts of the tin added to the remaining amount of tin, and add stainless steel. The inside of the pot is smelted, and the alloy is produced by stirring for one hour, and the temperature is gradually and evenly cooled. When the temperature drops to 340 添加, phosphorus or gallium is added, and the phosphorus or gallium is added in an amount of 100-3000 ppm;

(4) The stirred solder is poured into a mold and cast into a lead-free solder bar to obtain the product of the present invention.