P对Sn-Cu无铅钎料性能的影响

添加了P到Sn-Cu系无铅钎料中,测定了钎料的熔化温度、抗氧化性能和接头蠕变疲劳寿命。结果表明:在Sn0.7Cu中添加微量的P,提高了无铅钎料的抗氧化性能,对熔化温度基本无影响。Sn0.7Cu0.005P无铅钎料合金熔化温度的峰值为226.7℃,在恒定应力为2MPa的蠕变疲劳试验中,钎料接头蠕变疲劳寿命为337.357min。     

热输入及掺Ni对Sn-Ag钎料强度的影响

Sn-Ag共晶钎料中添加Ni颗粒,在钎料内部形成强化相,达到强化效果。研究了Ni颗粒的添加配比对强化效果的影响,并提出了热输入概念,通过调节热输入量控制钎料的强度。结果表明,φ(Ni)为5%是最佳配比,当热输入量为5.07时,其强度值最高,达60.71 MPa。比未添加Ni的钎料提高50%以上。     

锡铅稀土钎料合金高温蠕变性能试验研究

文中对比分析了Ｓｎ６０Ｐｂ４０和Ｓｎ－Ｐｂ－０．０５Ｒｅ两种钎料合金在多轴应力状态下的蠕变断裂规律,初步探讨了主控两种钎料复合金为断裂的力学因素,并从金属学角度初步探讨了两种钎料合金的蠕变断裂方式,着重分析了混合稀土对锡铅秆料合金蠕变性能的影响。     

Ni颗粒增强无铅复合钎料中IMC形态之演变

通过改变钎焊工艺曲线来控制热输入量。研究了Ni颗粒周围金属间化合物(IMC)以及钎料/基板界面处IMC的形态演变。结果表明,随着热输入量由低变高,Ni颗粒周围IMC形态从向日葵状向多边形状发展,最终成为遍布整个钎料层的细碎的IMC形态;而钎料/基板界面层,因Ni颗粒的加入,出现大量的三维孔洞状IMC。从而形成了Cu元素扩散的通道,使得界面层厚度增加且呈线性增长趋势。     

锡基无铅钎料的性能研究与新进展

介绍了现阶段锡基无铅钎料的使用和生产情况,归纳了钎料合金的特点,综述了不同系列无铅钎料的熔化特性、焊后的剪切强度及可焊性等,总结了目前无铅钎料研究所取得的新成果、新进展以及存在的问题。从锡晶须,虚焊等方面指出了无铅钎料可靠性的不足,并提出部分解决方案,指出了无铅钎料的发展趋势和应用前景。     

微量混合稀土对SnAgCu钎料合金性能的影响

通过向Sn-3.8Ag-0.7Cu钎料合金中添加微量的Ce基混合稀土，研究了不同稀土含量对SnAgCu合金物理性能、润湿性能及力学性能的影响，同时对显微组织进行了分析。试验结果表明，微量的混合稀土可以显著提高SnAgCu钎料接头在室温下的蠕变断裂寿命，尤其是当稀土的质量分数为0．1％时，其蠕变断裂寿命可以达到Sn-3.8Ag-0.7Cu钎料的7倍以上。通过对SnAgCuRE钎料合金物理、工艺及力学性能的测试，显微组织分析表明，随着稀土含量的增加，钎料的组织逐渐细化，但同时，稀土化合物的数量增多，对钎料的力学性能产生不利影响。综合考虑，最佳的稀土质量分数为0．05％－0．5％，不宜超过1．0％。     

Ag含量对Sn-Zn-Ag无铅钎料腐蚀性能的影响

在Sn-Zn共晶钎料中加入不同含量的Ag元素制成Sn-9Zn-xAg无铅钎料,利用失重法、扫描电镜的腐蚀形貌观察以及EDS成分分析,分析了Sn-9Zn-xAg无铅钎料在3%NaCl溶液浸泡腐蚀情况下的腐蚀行为,并与Sn-Pb以及Sn-Zn钎料进行比较.结果表明:随着Ag含量的增加,钎料合金的抗腐蚀性能有所提高.     

电迁移致无铅钎料微互连焊点的 脆性蠕变断裂行为

研究了电迁移条件下不同电流密度(0.8~1.27×10⁴A/cm²)和通电时间(0~96 h)对无铅钎料模拟微互连焊点的蠕变断裂行为的影响.研究结果发现,电迁移作用加速了焊点的蠕变断裂过程,随着电迁移通电时间的延长及电流密度的增加,其蠕变应变速率显著增大,而蠕变寿命逐渐缩短;电迁移还导致焊点蠕变断裂机制发生明显变化,在高电流密度或长时间通电的电迁移后,微互连焊点在服役条件下会发生由延性断裂向脆性断裂的转变.     

稀土含量对Sn—Pb—Re钎料SMT焊点热循环性能的影响

本文对不同稀土含量Ｓｎ－Ｐｂ－Ｒｅ钎料系焊点的热循环寿命进行了实验研究，结果表明，钎料中稀土含量为０．０５％－０．５％时，可使焊点的热循环寿命提高到普通Ｓｎ６０Ｐｂ４０钎料的２－３倍以上；     

Creep Life Assessment of Tin-Based Lead-Free Solders Based on Imaginary Initial Strain Rate

The creep properties of tin-based, lead-free solders, Sn-3.0Ag-0.5Cu and Sn-7.5Zn-3.0Bi, were investigated for the temperature range from 298 K to 398 K. The creep rupture time decreases with increasing initial stress and temperature. The Omega method is applied to the analysis of the solder creep curves. The creep rate is expressed by the following formula: , where and Ω are experimentally determined. The parameter , the imaginary initial strain rate, increases with increasing initial stress and temperature. The parameter Ω is temperature dependent, but less dependent on the initial stress. The apparent activation energy for is 108 kJ/mol in Sn-3.0Ag-0.5Cu and 83 kJ/mol in Sn-7.5Zn-3.0Bi. These values are close to the activation energy for the lattice diffusion of tin. The creep rupture time is calculated using the parameters and Ω. The calculated creep rupture time is in good agreement with the measured creep rupture time.     

Study on Cu particles-enhanced SnPb composite solder

The Sn-Pb solder is widely used in the electronics industry. With the development of surface mount technology and miniaturization of elements, mechanical properties of the solder are critical. Creep resistance and size stability of soldered joints are important for optical electronics. In the present work, Cu particles with a size of about 8 μm were added to the eutectic 63Sn-37Pb solder to improve the creep property of the soldering alloy. The contents of the Cu particles are 5 vol.% and 10 vol.% separately. The solder matrix is 63Sn37Pb particles with a normal size of 43 μm. The composite solder pastes are manufactured from a mixture of these particles with no-clean flux. Under reflow soldering, the metal particles were uniformly dispersed in the Sn-Pb alloy, and very thin intermetallic compounds were formed between the particles and matrix. To simulate practical soldering of printed circuit boards, a specially designed mini specimen with lap joint is used for the creep-rupture test. For the condition of ambient temperature, the creep-rupture lifetime of the soldered joint can be increased by one order quantitatively using the composite solder compared to the 63Sn37Pb eutectic solder. Other mechanical properties are measured also. In addition, the wetting property of the enhanced solder is good through the wettability test.     

Creep Properties of Composite Solders Reinforced with Nano- and Microsized Particles

In the present work the creep properties of Sn37Pb- and Sn0.7Cu-based composite solders reinforced with metallic nano- and microsized Cu and Ag particles have been studied. First, a series of volume percentages of reinforcements were selected to optimize the content of reinforcing particles. Then, the composite solder with optimum volume fraction of reinforcement particles, corresponding to the maximum creep rupture lifetime, was selected to investigate the effect of applied stress and temperature on the creep rupture lifetime of the composite solder joints. In the creep rupture lifetime test, small single-lap tensile-shear joints were adopted. The results indicate that composite solders reinforced with microsized particles exhibit better creep strengthening than composite solders reinforced with nanosized particles, although the mechanical tensile shear strength of composite solder joints reinforced with nanosized particles may be higher than those reinforced with microsized particles. Moreover, the creep strengthening action of the reinforcement particles is more obvious under conditions of lower applied stress or lower test temperature. Strengthening by metallic Cu or Ag reinforcement particles decreases with increasing temperature or applied stress. The Sn0.7Cu-based composite solder reinforced with microsized Ag particles is a low-cost lead-free solder that is easy to process and may have good market potential.     

Sn-9Zn/Cu焊点的结合强度与抗蠕变性能

基于前期进行的锡锌合金无铅钎料新型助焊剂研究,实验考查了其中二氯化锡活化剂含量水平对Sn-9Zn/Cu焊点剪切强度和常温抗剪切蠕变性能的影响.结果表明:就上述焊点强度而言,二氯化锡含量的影响与它对润湿性的影响[5]不尽一致,存在一个最佳的质量分数5%,超过该含量后尽管润湿性还继续提高,上述强度值却均会下降.在二氯化锡质量分数为5%时制得的焊点在剪切实验中呈良好韧性断裂模式.实验还显示:焊剂中较高的松香浓度明显有益于焊点的抗剪切蠕变强度,而对瞬时剪切强度影响不大.     

Constitutive Relations for Creep in a SnCu-Based Composite Solder Reinforced with Ag Particles

In the present work, the creep strain of the composite solder joint is measured using a stepped load creep test on a single specimen. Based on the creep strain tests, constitutive relations for the steady-state creep rate are determined for the Ag-particle-reinforced Sn-0.7Cu-based composite solder joint. In addition, creep strain tests on the Sn-0.7Cu solder joint are performed as a comparison. It is found that the activation energy of the Ag-particle-reinforced Sn-0.7Cu-based composite solder joint is higher than that of the Sn-0.7Cu solder joint. At the same time, the stress exponent of the Ag-particle-reinforced Sn-0.7Cu-based composite solder joint is higher than that of the Sn-0.7Cu solder joint. It is expected that the creep resistance of the Ag-particle-reinforced Sn-0.7Cu-based composite solder joint will be superior to that of the Sn-0.7Cu solder joint. Finally, the creep deformation mechanisms of the solder joint are discussed.     

Sn-Zn-Bi-X(Ag,Cu)系钎料的断裂韧性研究

通过对两种具有代表性的无铅软钎料断口的分析,介绍了Sn-Zn-Bi-X(Ag,Cu)系钎料合金的断裂韧性的初步研究结果,发现Bi固溶于钎料基体导致了钎料合金脆性的增加,随着Bi含量的增加,脆性随之增大。同时发现,钎料的冷却方式对钎料的脆性倾向有较大的影响。     

Creep and rupture behavior of Cu wire/lead-free solder-alloy joint specimen

Creep and rupture behavior of Cu wire/lead-free solder-alloy joint specimens have been investigated using Sn-3.5% Ag and Sn-0.5% Cu alloys. A Sn-37% Pb solder alloy is also used as a reference material. The present authors have fabricated a creep-rupture testing machine for Cu wire/solder-alloy joint specimens, performed creep and rupture tests at 303 K and 403 K, analyzed the characteristics of the creep and rupture behavior, and compared these to test specimens cut from the same alloy ingots. It is also found that the rupture strength of the joint specimens is related to the rupture strength of the alloys.     

球栅阵列封装中SnPb焊点的应力应变分析

基于SnPb焊料的统一粘塑性Anand本构模型,运用ANSYS有限元软件分析了球栅阵列封装中复合SnPb焊点在热循环过程中的应力、应变的分布,观察到SnPb焊料的蠕变行为和应力松弛现象,结果证明:外侧焊点经受的应力、应变范围比内侧焊点大;焊点的最高应力区域出现在Sn60Pb40焊料的最外缘处,最高应变区域出现在Pb90Sn10焊料与UBM层接触面的最上缘处.