CN1475327A

CN1475327A - Antioxidation leadless welding material

Info

Publication number: CN1475327A
Application number: CNA03129619XA
Authority: CN
Inventors: 顾小龙; 杨倡进
Original assignee: ASIA GENERAL ELECTRONICS Co Ltd
Current assignee: Zhejiang Prov. Metallurgy Inst., Co., Ltd.,
Priority date: 2003-06-28
Filing date: 2003-06-28
Publication date: 2004-02-18
Anticipated expiration: 2023-06-28
Also published as: CN1238153C

Abstract

An antioxidizing Pb-free solder for PCB is aimed at reducing cost and improving soldering performance. It has 5 formulas and one of them is Cu (2-5 wt.%), Sb (0.01-0.5), Ag (0.01-0.5), In (0.002-0.2), Ni (0.01-0.5), Ga (0.002-0.1), P (0.002-0.1), RE (0.01-2) and Sn (rest). Other four are also disclosed. Its advantages are strong antioxidizing performance and no poison and pollution.

Description

Oxidation resistant lead-free solder

Technical field

The invention belongs to welding material, relate to the lead-free solder on the printed circuit board (PCB)

Background technology

Electronics assembling and to encapsulate the most frequently used welding material be the plumbous eutectic solder of tin in the electronics industry at present is characteristics such as that though it has is with low cost, good conductivity, mechanics welding performance are good.But plumbous and plumbous compound is a poisonous and harmful substance, and scolder is detrimental to health in production and use, and is carcinogenic easily, and the welding discarded object can serious environment pollution.Countries in the world are to the use growing interest of lead, and the cry that bans use of is surging day by day.In recent years, the research and development of lead-free solder development is very fast.From domestic and foreign research results, based on tin (Sn), interpolation can produce metallic elements such as the copper (Cu), silver (Ag), zinc (Zn), antimony (Sb), indium (In), bismuth of low temperature eutectic, improves the performance of alloy by solder alloyization, improves braze ability.The composition of this lead-free solder mainly concentrates on series such as tin/copper, tin/silver, tin/zinc, tin/indium, tin/bismuth.Because this lead-free solder main component is a tin, its fusing point is higher approximately 50 ℃ than the plumbous eutectic solder of tin, the also corresponding raising of serviceability temperature thereupon, thereby easily produce oxidation, influence welding quality, the particular importance so the antioxygenic property of lead-free solder seems, but from existing report, the anti-oxidant problem of lead-free solder is still unresolved at present; Owing to indium, silver cost an arm and a leg, resource-constrained all makes described lead-free solder again, is difficult to popularize in an all-round way in electronics industry use.

Summary of the invention:

The objective of the invention is will be at prior art problems, seeks that a kind of antioxygenic property is good, combination property is excellent, cheap, resourceful lead-free solder.

The design that the present invention is total: adopt high tin, low copper, low silver, add a certain amount of rare earth, indium, gallium, phosphorus and an amount of nickel, antimony prepares oxidation resistant lead-free solder as alloy element.

Adding gallium (Ga), phosphorus (P) element can significantly improve the antioxygenic property of alloy, reduce the degree of oxidation of scolder in the welding process; Add nickel (Ni) element, help and solve the solder joint bridging; Add mixed rare-earth elements (RE), mainly comprise element and oxides thereof such as cerium, lanthanum, not only improve the wetability of alloy, and can crystal grain thinning, can significantly improve mechanical property, welding performance, the cold and hot working Performance And Reliability of tin/copper alloy, in the time of satisfying electronics industry and be welded on electric elements and electronic component on the printed circuit board (PCB) to the requirement of scolder.It is a kind of anti-oxidant, nontoxic, pollution-free, combination property is superior, the lead-free solder of cheap, environment-friendly type.

The specific embodiment:

According to total inventive concept, the chemical constituent of oxidation resistant lead-free solder of the present invention and weight content percentage ranges (Wt%) thereof can adopt following five preferable invention schemes.

1. (2.0-5.0) Cu, (0.01-0.5) Ag, (0.01-0.5) Sb, (0.002-0.2) In, (0.01-0.5) Ni, (0.002-0.1) Ga, (0.002-0.1) P, (0.01-2.0) RE; Surplus is the impurity of Sn and common content.

2. (2.0-5.0) Cu, (0.01-0.5) Ag, (0.002-0.2) In, (0.002-0.1) Ga, (0.002-0.1) P, (0.01-2.0) RE; Surplus is the impurity of Sn and common content.

3. (0.05-2.0) Cu, (2.0-5.0) Sb, (0.002-0.2) In, (0.002-0.1) Ga, (0.002-0.1) P, (0.01-2.0) RE; Surplus is the impurity of Sn and common content.

4. (0.05-2.0) Cu, (0.002-0.2) In, (0.01-0.3) Sb, (0.002-0.1) Ga, (0.002-0.1) P, (0.01-2.0) RE; Surplus is the impurity of Sn and common content.

5. (1.0-4.0) Ag, (0.05-2.0) Cu, (0.002-0.2) In, (0.002-0.1) Ga, (0.002-0.1) P, (0.01-2.0) RE; Surplus is the impurity of Sn and common content.

Five inventions more than coming from an inventive concept have three common technical characterictics.The one, the Ga and the P of same amount are all arranged, guaranteed that the lead-free solder of invention all has good antioxygenic property; The 2nd, the identical rare earth element Re of content is all arranged, can significantly improve the mechanics of scolder, processing characteristics; The 3rd, owing to all adopt high Sn, low Cu, low Ag etc. significantly to reduce production costs.

By the alloying component for preparing, preferably block or granular (rare earth, gallium, phosphorus, nickel are middle alloy) puts into vacuum melting furnace or the melting of non-vacuum melting stove, under normal pressure, 850 ℃-900 ℃ temperature kept 1-2 hour, and casting can obtain the oxidation resistant lead-free solder alloy.Further processing can be produced oxidation resistant lead-free solder silk and bar.

Remarkable result of the present invention is that scolder has anti-oxidant and excellent hot and cold processing characteristics; The alloy structure refinement has excellent mechanical property; The bridging and the lead-in wire corrosion problem of solder joint have been solved; Improve hear resistance and corrosion resistance, increased the solderability of scolder, reduced the quantity of oxidizing slag in the scolder use.This lead-free solder is not only nontoxic, pollution-free, and its combination property is superior, and cheap.Can satisfy electric elements and electronic component requirement of welding on printed circuit board (PCB).

Claims

1, oxidation resistant lead-free solder, its component and weight content percentage ranges are:

2.0-5.0Cu, 0.01-0.5Ag, 0.01-0.5Sb, 0.002-0.2In, 0.01-0.5Ni, 0.002-0.1Ga, 0.002-0.1P, 0.01-2.0RE; Surplus is the impurity of Sn and common content.

2, oxidation resistant lead-free solder, its component and weight content percentage ranges are:

2.0-5.0Cu, 0.01-0.5Ag, 0.002-0.2In, 0.002-0.1Ga, 0.002-0.1P, 0.01-2.0RE; Surplus is the impurity of Sn and common content.

3, oxidation resistant lead-free solder, its component and weight content percentage ranges are:

0.05-2.0Cu, 2.0-5.0Sb, 0.002-0.2In, 0.002-0.1Ga, 0.002-0.1P, 0.01-2.0RE; Surplus is the impurity of Sn and common content.

4, oxidation resistant lead-free solder, its component and weight content percentage ranges are:

0.05-2.0Cu, 0.002-0.2In, 0.01-0.3Sb, 0.002-0.1Ga, 0.002-0.1P, 0.01-2.0RE; Surplus is the impurity of Sn. and common content.

5, oxidation resistant lead-free solder, its component and weight content percentage ranges are:

1.0-4.0Ag, 0.05-2.0Cu, 0.002-0.2In, 0.002-0.1Ga, 0.002-0.1P, 0.01-2.0RE; Surplus is the impurity of Sn and common content.