应力对Ag颗粒增强SnCu基复合钎料蠕变性能的影响

使用搭接面积为1mm2的单搭接钎焊接头,研究了恒定温度下应力对Ag颗粒增强SnCu基复合钎料钎焊接头蠕变寿命的影响,结果表明:Ag颗粒增强SnCu基复合钎料的蠕变抗力优于99.3Sn0.7Cu基体钎料;随着应力的增大,复合钎料及其基体钎料钎焊接头的蠕变寿命均呈下降趋势,且应力对复合钎料钎焊接头蠕变寿命的影响比基体钎料明显.     

纳米结构强化的新型Sn-Ag基无铅复合钎料

通过外加法向Sn-3.5Ag钎料中加入质量分数为1%,2%和3%的纳米级多面齐聚倍半硅氧烷(polyhedral oligomeric silsesquioxanes,POSS)颗粒制备无铅复合钎料.系统研究POSS颗粒的显微组织,钎料的熔化特性、润湿性能和力学性能.结果表明:POSS颗粒的加入并没有改变Sn-Ag基复合钎料熔化温度.复合钎料的铺展面积均有所增加,润湿角有所下降,表现了良好的润湿性.POSS颗粒的加入显著提高钎料钎焊接头的剪切强度.     

Ag颗粒增强复合钎料钎焊接头蠕变断裂及强化机理研究

测定了不同应力和温度下Ag颗粒增强复合钎料及基体钎料63Sn37Pb钎焊接头蠕变寿命,分析了Ag颗粒增强复合钎料及基体钎料钎焊接头蠕变断裂机理.表明:Ag颗粒增强复合钎料钎焊接头蠕变寿命优于基体钎料;Ag颗粒表面Ag-Sn金属间化合物形成及Ag颗粒对富Pb层阻碍作用是复合钎料钎焊接头蠕变性能提高的主要因素;钎焊接头Cu基板上一薄层富Pb相区形成是蠕变裂纹主要原因.     

纳米结构强化无铅焊点的力学性能

新型的无铅钎料不仅要具备含铅钎料的工艺性能,更重要的是要有更高的力学性能,特别是焊接接头的抗蠕变能力。将纳米级多面齐聚倍半硅氧烷(Polyhedral oligomeric silsesquioxanes,POSS)颗粒作为增强相添加到基体钎料中,能够有效地改善Sn-3. 5Ag基复合钎料的性能。研究了不同种类POSS增强颗粒对Sn-3. 5Ag钎料显微组织和力学性能的影响,确定出POSS增强颗粒复合钎料的最佳配比,并对最佳配比复合钎料在不同温度不同载荷条件下的蠕变寿命进行了研究。结果表明：POSS颗粒质量分数小于2%时,可以抑制基板界面处初晶金属间化合物的生长;复合钎料的抗剪切强度明显提高;低温时,最大蠕变寿命明显改善。     

温度对Cu颗粒增强复合钎料蠕变性能的影响

蠕变性能是影响钎焊接头可靠性的重要指标之一.采用搭接面积为1 mm2的单搭接钎焊接头,在恒定载荷下,测定了Cu颗粒增强锡铅基复合钎料钎焊接头的蠕变寿命,分析并讨论了温度对该复合钎料蠕变寿命的影响.结果表明:Cu颗粒增强的锡铅基复合钎料的蠕变抗力优于传统63Sn37Pb共晶钎料;钎焊接头蠕变寿命随温度的升高而降低,并且温度对复合钎料钎焊接头蠕变寿命的影响较传统63Sn37Pb钎料明显.     

等温时效对新型Sn-Ag基复合钎料显微组织和力学性能的影响

研究了等温时效对Sn-3.5Ag共晶钎料及其复合钎料的力学性能和显微组织变化的影响。为了弥补传统复合钎料制备和服役中强化颗粒容易粗化的问题, 制备了不同种类最佳配比的具有纳米结构的有机无机笼型硅氧烷齐聚物(POSS)颗粒增强的Sn-Ag基复合钎料。对钎焊接头在不同温度（125、150、175℃）下进行时效,通过SEM和EDAX分析了钎料与基板间金属间化合物层(IMC)的生长情况。结果表明, 经过不同温度时效,复合钎料钎焊接头界面处金属间化合物的生长速率比Sn3.5Ag共晶钎料慢, 复合钎料的IMC生长的激活能分别为80、97和77kJ/mol,均高于Sn3.5Ag共晶钎料。经过150℃时效1000h后,复合钎料钎焊接头的剪切强度分别下降了22%、13%和18%,下降幅度相当或明显小于Sn-3.5Ag钎料钎焊接头。      

Ag颗粒含量对SnCu基复合钎料性能的影响

利用颗粒增强原理研制了新型Ag颗粒增强SnCu基复合钎料,研究了Ag颗粒不同含量对复合钎料性能影响.结果表明:当Ag含量(体积分数)为5%时,复合钎料铺展面积最大,润湿角最小,钎焊接头蠕变寿命最长,比基体钎料提高23倍.     

添加Ag元素对铝软钎焊用Sn-1.5Zn系钎料性能的影响

研究了添加不同含量Ag元素对铝软钎焊用Sn-1.5Zn系钎料合金的熔化特性、显微组织、润湿性及钎焊接头抗腐蚀性能的影响。研究结果表明,Ag元素的添加缩短了Sn-1.5Zn钎料的熔程,细化了显微组织;采用润湿平衡法测量结果发现,添加Ag元素提高了钎料对铝基体的最大润湿力Fmax,但使润湿时间t0增加;采用3%(质量分数)浓度盐水溶液浸泡焊点实验结果表明,添加Ag元素提高了钎焊接头的抗腐蚀性。     

硅氧烷齐聚物颗粒增强Sn-Ag基复合钎料的熔化特性

具有纳米结构的有机-无机笼型硅氧烷齐聚物（POSS）作为强化相的POSS/Sn-3.5Ag复合钎料可有效地改善基体钎料钎焊接头的力学可靠性。在前期试验的基础上,采用差热分析试验的方法分析了POSS 质量分数为3%的POSS/Sn-Ag复合钎料中POSS颗粒的熔化特性。结果表明,3% POSS/Sn-Ag复合钎料的熔化温度与Sn-3.5Ag共晶钎料相近,POSS颗粒的加入对其熔化温度影响不大,说明复合钎料在熔化特性上可以满足工艺性能的要求。此外,差热分析计算表明,3% POSS/Sn-Ag复合钎料在冷却过程中具有更高的表观活化能值,说明POSS强化相可能主要存在于Sn晶粒的晶界处。     

Ni元素对Sn-9Zn-3Bi无铅钎料显微组织和性能的影响

利用真空箱式电阻炉制备了Sn-9Zn-3Bi-xNi无铅钎料合金,并对其显微组织和主要性能(熔点、熔程、抗氧化性、润湿性、剪切强度)及钎焊接头断口形貌进行了分析。结果表明,少量Ni的加入可以细化Sn-9Zn-3Bi合金的显微组织,而对其熔点影响较小。当Ni添加量为0.1%和0.5%时,钎料的熔程变化不大,Ni添加量为1%时,钎料的熔程增大比较明显。随着Ni添加量增多,无铅钎料的抗氧化性能和润湿性能提高。Ni添加量在0.1%和0.5%时,钎焊接头的剪切强度变化不大,但韧性增加;Ni添加量在1%时,钎焊接头的剪切强度略有增大,但韧性降低。     

Effect of Ni Content on Mechanical Properties and Corrosion Behavior of Al/Sn－9Zn－xNi/Cu Joints

The effects of Ni content on the microstructure and the wetting behavior of Sn-9Zn-xNi solders on Al and Cu substrates, as well as the mechanical properties and electrochemical corrosion behavior of Al/Sn-9Zn-xNi/Cu solder joints, were investigated. The microstructure of Sn-9Zn-xNi revealed that tiny Zn and coarsened Ni 5 Zn 21 phases dispersed in the β-Sn matrix. The wettability of Sn-9Zn-xNi solders on Al substrate was much better than that on Cu substrate. With increasing Ni content, the wettability on Cu substrate was slightly improved but became worse on Al substrate. In the Al/Sn-9Zn-xNi/Cu joints, an Al4.2Cu3.2Zn0.7 intermetallic compound (IMC) layer formed at the Sn-9Zn-xNi/Cu interfaces, while an Al-Zn-Sn solid solution layer formed at the Sn-9Zn-xNi/Al interface. The mixed compounds of Ni3Sn4 and Al3Ni dispersed in the solder matrix and coarsened with increasing Ni content, thus leading to a reduction in shear strength of the Al/Sn-9Zn-xNi/Cu joints. Al particles were segregated at both interfaces in the solder joints. The corrosion potentials of Sn-9Zn-xNi solders continuously increased with increasing Ni content. The Al/Sn-9Zn-0.25Ni/Cu joint was found to have the best electrochemical corrosion resistance in 5% NaCl solution.     

Development of a microwave sintered TiO2 reinforced Sn–0.7wt%Cu–0.05wt%Ni alloy

The use of reinforcing nano-size ceramic particulates is a promising method to improve the mechanical and thermal properties of lead-free solder materials. In addition, advanced fabrication processes routes such as microwave sintering powder metallurgy (PM) enhance properties in the fabrication of composite solders. To elucidate the mechanisms underlying the improvements in mechanical and thermal properties, Sn–Cu–Ni with TiO₂ nano-composite additions, fabricated via a microwave sintering PM method, were investigated using state-of-the-art characterization techniques. Synchrotron micro-X-ray fluorescence (XRF) results detected trace Ti in the solder matrix. This was consistent with X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM) results which indicated that nano crystals were within the Sn matrix. It is possible these nano crystal form due to the migration of Ti during the rapid high energy microwave heating. A hypothesis of improved thermal and mechanical properties of nano-composite solders is discussed based on the results and the microwave sintering PM route was discussed as a promising method for next generation lead-free solder processing.     

High-temperature shear strength of lead-free Sn-Sb-Ag/Al2O3 composite solder

The lead-free Sn-1.7Sb-1.5Ag solder alloy and the same material reinforced with 5 vol.% of 0.3-μm Al₂O₃ particles were synthesized using the powder-metallurgy route of blending, compaction, sintering, and extrusion. The mechanical properties of both monolithic and composite solders were studied by shear punch testing (SPT) at temperatures in the range of 25-130 °C. Depending on the test temperature, the shear yield stress (SYS) increased by 4.8-8.8 MPa, and ultimate shear strength (USS) increased by 6.2-8.8 MPa in the composite material. The strength improvement was mostly due to the CTE mismatch between the matrix and the particles, and to a lesser extent to the Orowan strengthening mechanism of the submicro-sized Al₂O₃ particles in the composite solder. The contribution of each of these mechanisms was used in a modified shear lag model to predict the total composite-strengthening achieved.     

Development of a Sn–Ag–Cu solder reinforced with Ni-coated carbon nanotubes

In this study, Ni-coated carbon nanotubes (Ni-CNTs) were incorporated into the 95.8Sn-3.5Ag-0.7Cu solder alloy using the powder metallurgy route. Up to 0.3 wt% of Ni-CNTs were successfully incorporated. The effects of Ni-CNTs on the physical, thermal and mechanical properties of Sn–Ag–Cu solder alloy were investigated. With the addition of increasing weight percentages of Ni-CNTs, the composite solders showed a corresponding decrease in density values and improved wetting properties. The thermomechanical property results showed an improvement in thermal stability for the composite solders. Mechanical characterization revealed an improvement in ultimate tensile strength (up to 12%) and 0.2% yield strength (up to 8%) with the addition of 0.05 wt% Ni-CNTs in the solder.     

Creep behavior in Cu and Ag particle-reinforced composite and eutectic Sn-3.5Ag and Sn-4.0Ag-0.5Cu non-composite solder joints

Creep properties were determined for small, geometrically realistic Pb-free solder joints. Solder joints were prepared with eutectic Sn-3.5Ag and Sn-4.0Ag-0.5Cu solder alloys. Composite solder joints were made using the eutectic Sn-3.5Ag alloy as the matrix with 15 vol % of mechanically added 6 m size Cu and 4 m size Ag reinforcing particles. Creep tests were conducted on these joints at 25 °C, 65 °C and 105 °C representing homologous temperatures ranging from 0.61 to 0.78. Qualitative and quantitative evaluations of creep behavior were obtained from the distortion of excimer laser-induced surface ablation markings on the solder joint. Various creep parameters, such as global and localized creep strain, variation of creep strain and strain-rate, activation energy for creep, and the onset of tertiary creep were determined. General findings in this study revealed that the creep resistance in composite solder joints is significantly improved with Cu particle reinforcements. In contrast, the improvement in the creep properties of Ag particle-reinforced composite solder joints was far less even though highly uniform deformation in the joint was observed. The strain noted at the onset of tertiary creep for Cu and Ag reinforced composite solder joints was typically lower compared to non-composite solder joints. The activation energies for creep were similar for all the solder materials investigated in this study. © 2001 Kluwer Academic Publishers     

低银Sn-0. 45Ag-0. 68Cu-X 无铅钎料性能的对比研究

目的制备一种新型低银亚共晶Sn-0.45Ag-0.68Cu-X(SAC-X)无铅钎料,并对其综合性能进行探究。方法参照国家标准,对其漫流性、润湿性及力学性能进行了测试,并与Sn-37Pb,Sn-0.7Cu,Sn-3.5Ag-0.6Cu钎料进行了对比。结果 4种钎料漫流性和润湿性大小依次为:Sn-37Pb,Sn-3.5Ag-0.6Cu,SAC-X,Sn-0.7Cu,其中SAC-X钎料铺展率达78.5%,润湿时间为1.3 s,最大润湿力为3.18 m N;SAC-X钎料抗拉强度(40 MPa)与高银Sn-3.5Ag-0.6Cu钎料(44 MPa)相差不大,但延伸率是高银Sn-3.5Ag-0.6Cu的1.89倍。结论低银SAC-X钎料综合性能优良,与Sn-3.5Ag-0.6Cu钎料相差不大。