摘要传统Sn-Ag-Cu系无铅钎料具有优异的综合性能，但由于含银量较高，过高的成本限制了其在行业内的普遍应用。本论文选取现有低银无铅钎料中含Ag量最低的Sn-0。3Ag-0。7Cu钎料为研究对象，在大幅度降低Ag元素含量的同时，向其中添加稀土元素Pr来改善钎料的性能，研究不同Pr添加量对低银无铅钎料润湿性能、基体组织形貌以及微焊点力学性能的影响，从而研发出具有低成本、高性能的新型无铅钎料。 87883

    通过润湿平衡法，研究了不同Pr元素添加量对Sn-0。3Ag-0。7Cu钎无铅钎料润湿性能的影响。试验结果表明：适量的加入稀土元素Pr能够有效地改善低银锡铜无铅钎料的润湿性能Pr的最佳添加量为0。05 wt。％，最大添加量不应超过0。25 wt。％，过量会产生负影响。

研究发现，添加适量稀土元素Pr能够显著提高微焊点的力学性能，当添加量为0。05 wt。％时，微焊点的力学性能最佳。同时当Pr元素含量为0。05 wt。%时，焊点内部为细小且均匀分布的金属件化合物颗粒。时效试验的结果表明，微焊点力学性能会随时效时间的增加而下降。当添加Pr的量为0。05wt。%时，焊点在时效后具有最好的综合性能。

毕业论文关键词  无铅钎料  低银  Sn-Ag-Cu  稀土元素  润湿性能  力学性能  显微组织

毕业设计说明书外文摘要

Title  Study on low silver lead-free Sn-Ag-Cu solder

Abstract Traditional Sn-Ag-Cu based lead-free solder has excellent comprehensive performance, but because of having a high silver content, the high cost limits its widespread application in the industry。 In this paper, the existing select low silver lead-free solder containing Ag compound lowest amount of Sn-0。3Ag-0。7Cu solder for the study, a significant reduction in the Ag element content at the same time, a rare earth element Pr added thereto to improve solder performance。 the effect of different addition amount Pr of low silver lead-free solder wetting properties of the matrix microstructure and mechanical properties of the micro-joints, which has developed a low cost, high performance of new lead-free solder。

By wetting balance method to study the effects of different elements of Pr additions on Sn-0。3Ag-0。7Cu solder lead-free solder wettability。 The results show that: the right amount of adding rare earth elements Pr can effectively improve low silver  lead-free solder’s wettability。The optimal addition amount of Pr is 0。05 wt。%, the maximum amount should not exceed 0。25 wt。%,or it will have a negative impact。源-于,优Y尔O论U文.网wwW.youeRw.com 原文+QQ75201,8766

The study found that adding an appropriate amount of rare earth elements Pr can significantly improve the mechanical properties of the micro-joints, when the addition amount id 0。05 wt。%, micro-joints have the best mechanical properties。 At the same time when Pr element content of 0。05 wt。%, The solder joint is fine and uniform distribution of metal compound particles。 Results of aging experiments showed that the mechanical properties of the micro-joints are subject to increase efficiency and decrease time。 When the amount of added Pr is 0。05wt。%, The solder joint after aging has the best comprehensive performance。

Keywords  Lead-free  solder  low silver  Sn-Ag-Cu  rare earth  elements  wettability  mechanical properties  microstructure

目   次

1  绪论 1

1。1引言 1

1。2无铅钎料的研究现状 1

1。3  SnAgCu无铅钎料的研究现状 1