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1、石墨烯增强Sn-Ag-Cu复合无铅钎料的设计与性能研究原文地址：http:/ ?天津大学硕士学位论文石墨烯增强 Sn-Ag-Cu 复合无铅钎料 的设计与性能研究Design and Property Study on a Sn-Ag-Cu Lead-free Solder Reinforced with Graphene学科专业：材料加工工程 研 究 生：刘向东 指导教师：徐连勇副教授天津大学材料科学与工程学院 2012 年 12 月独创性声明本人声明所呈交的学位论文是本人在导师指导下进行的研究工作和取得的 研究成果，除了文中特别加以标注和致谢之处外，论文中不包含其他人已经发表 或撰写过的研究
2、成果， 也不包含为获得 天津大学 或其他教育机构的学位或证 书而使用过的材料。 与我一同工作的同志对本研究所做的任何贡献均已在论文中 作了明确的说明并表示了谢意。学位论文作者签名：签字日期：年月日学位论文版权使用授权书本学位论文作者完全了解 天津大学有关保留、使用学位论文的规定。特授权 天津大学 可以将学位论文的全部或部分内容编入有关数据库进行检 索，并采用影印、缩印或扫描等复制手段保存、汇编以供查阅和借阅。同意学校 向国家有关部门或机构送交论文的复印件和磁盘。 （保密的学位论文在解密后适用本授权说明）学位论文作者签名： 签字日期： 年 月 日导师签名： 签字日期： 年 月 日中文摘要在无铅钎
3、料中，Sn-Ag-Cu 系钎料因其良好的力学性能及可靠性，目前被广 泛的应用。但是，随着微/纳机电系统技术的不断进步，微电子器件不断向小型 化、轻量化、功能化发展。传统的无铅钎焊技术已经难以满足钎焊接头可靠性的 要求。因此，急需开发出一种新型无铅钎料以满足更为苛刻的服役条件。 一个可行且具有前景的解决方案就是引入强化相，制备出复合钎料。在本研 究中，采用具有超强的力学性能、热稳定性及导电性的新型二维纳米材料石墨烯 作为强化相，加入传统的 Sn-Ag-Cu 钎料中形成复合钎料。本文的主要工作可分 为两部分。 (1)利用粉末冶金法成功制备了石墨烯纳米片（GNSs）复合无铅钎料，并测 试了材料的一系
4、列物理性能及微观组织。随着 GNSs 添加量的增加，复合材料的 润湿性相应得到提高，但熔点没有明显变化。热机械分析显示，GNSs 可以有效 降低复合钎料的线膨胀系数。另外，GNSs 的引入提高了复合钎料的抗拉强度但 降低了延展性。 (2)研究了复合钎料与 Cu 基板间在回流钎焊中， 及固态等温时效中界面处金 属间化合物（IMC）的生长情况。结果表明，不论在回流钎焊过程中，还是固态 等温时效中，相比 SAC 钎料，复合钎料的 IMC 层的生长都较慢，经计算其扩散 系数也较小。这说明，GNSs 可以有效抑制界面 IMC 在回流及时效过程中 IMC 的生长，防止 IMC 过度粗大影响焊点的可靠性。关
5、键词：Sn-Ag-Cu 无铅钎料；石墨烯；力学性能；金属间化合物；ABSTRACTAmong all the developed lead-free solders, Sn-Ag-Cu alloys have been widely accepted as the most promising lead-free solders because of their optimal mechanical properties and reliability. However, with the advancement of micro/nanosystem technologies, microe
6、lectronic devices have evolved to become smaller, lighter, and more functional. Conventional lead-free solder technology may not guarantee the required joint reliability in such cases. Hence, the development of new lead-free solders is driven by the urgent requirements posed by the smaller, lighter,
7、 and more functional microelectronic devices. An attractive and potentially feasible method to enhance the performance of a lead-free solder is to introduce reinforcements into a conventional alloy, so as to form a composite lead-free solder. In this study, the author attempt to introduce graphene a
8、s the nano-reinforcement, which have superior thermal, electrical, and mechanical properties and can serve as an ideal reinforcement in electronic packaging material. This thesis mainly covers following two parts: First, varying weight fractions of graphene nanosheets (GNSs) were successfully incorp
9、orated into lead-free solder using the powder metallurgy route, and the physical, thermal, and mechanical properties of the nanocomposite solder were characterized. With the increasing addition of graphene nanosheets, the nanocomposite solders showed a corresponding improvement in its wetting proper
10、ty but an insignificant change in its melting point. The thermomechanical analysis showed that the presence of graphene nanosheets can effectively decrease the coefficient of thermal expansion (CTE) of the nanocomposites. Furthermore, an improvement in UTS and a decrease in ductility were recorded w
11、ith the addition of graphene nanosheets. Then, The formation and growth kinetics of the intermetallic compounds (IMC) during the liquidsolid reactions and solid-state aging between composite solder and Cu substrates were investigated, and the results were compared to the SAC/Cu system. Experimental
12、results showed, during both liquidsolid reactions and solid-state aging, the interfacial IMC thickness of the unreinforced solder joints was observed to grow faster than that of the composite solder joints. Calculations suggest that the growth rate constant of composite is lower. It indicates that t
13、hat the presence of a smallamount of GNSs is effective in suppressing the growth of the overall IMC layer, which can prevent the IMCs excessive growth and enhance solder joints reliability.Key words ： Sn-Ag-Cu lead-free solder; graphene nanosheets; mechanics;intermetallic compound;目录目录 . I?第一章 绪论 .1? 1.1 前言 .1? 1.2 锡铅钎料 .1? 1.3 钎料的基本性能 .2? 1.3.1 熔点 .2? 1.3.2 润湿性 .3? 1.3.3 钎料-基板间的界面反应 .3? 1.3.4 电导率 .4
