稀土对Zn20Sn高温无铅钎料组织与性能的影响

向Zn20Sn高温无铅钎料中添加微量铈镧混合稀土（RE）,研究了RE的添加量对该钎料合金显微组织及性能的影响。结果表明,添加微量RE的合金显微组织中出现含RE的金属间化合物（IMC）。随着RE的添加,形状各异的IMC的数量显著增加。RE质量分数为0.5%~1.0%的合金的固相线温度不变,而液相线温度略有降低。当RE质量分数为0.5%时,钎料在Cu基板上的铺展面积最大,比Zn20Sn钎料提高了57.6%。但随着RE的继续添加,钎料的润湿性降低。当RE质量分数超过0.1%时,钎料的显微硬度和电阻率随着RE含量的增加而增大。综合考虑,合适的RE添加量为质量分数0.5%。     

混合稀土对Sn-0.70Cu-0.05Ni钎料组织与性能的影响

向Sn-0.70Cu-0.05Ni无铅钎料中添加微量混合稀土元素RE(主要是La和Ce),研究了RE添加量对该钎料合金显微组织及性能的影响.结果表明,添加微量的RE能显著细化该钎料合金组织,抑制金属间化合物的生长,改善合金的组织分布,提高钎料的润湿性及力学性能.当w(RE)为0.10%时,钎料的润湿力,拉伸强度分别为3...     

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。     

稀土改性的Sn-58Bi低温无铅钎料

研究了微量稀土对Sn-58Bi低温钎料的改性作用.试验添加质量分数为0.1 ?组混合稀土的无铅材料,并对比Sn-58Bi和Sn-58Bi0.5Ag合金.观察了钎料显微组织的变化并做了定量分析,采用DSC测试了钎料的熔化温度,同时测量了钎料的润湿性能、接头强度与硬度.结果表明,微量稀土添加细化了Sn-58Bi钎料合金的显微组织,对钎料的熔化温度几乎没有影响,能显著改善Sn-58Bi钎料的润湿性能和接头剪切强度,而且改善的程度优于添加微量Ag对Sn-58Bi钎料的作用.     

Ag和RE对SnAgCuRE无铅钎料拉伸性能的影响

利用正交试验法,对SnAgCuRE系钎料合金的拉伸性能进行了检验。结果表明:SnAgCuRE系钎料合金的拉伸性能与Ag和RE的添加量密切相关,即拉伸强度会随Ag含量增大而提高;延伸率受RE影响最大,并在w(RE)为0.1%时延伸率和拉伸强度都达到最佳。当w(RE)达到0.5%时,会导致延伸率的下降。     

新型Al-Si-Cu-Ge系钎料研究

研究了用于铝合金钎焊的新型Al-Si-Cu-Ge系钎料,通过快冷工艺制备了厚度90μm～150μm的钎料薄带.对所研究钎料的熔化温度区间及金相组织进行了分析和判定,结果表明:与Al-9.6Si-20Cu钎料相比,钎料熔化温度大幅降低;普通钎料和快冷钎料的固相线相差30℃左右,液相线差别约5℃;普通钎料的微观组织主要由Al-Si-Cu-Ge、Al-Si-Ge和Al-Cu共晶相、Si-Ge先析出相及θ(Al2Cu)相组成;快冷钎料晶粒尺寸范围约1 μm～5μm.     

新型Sn-Ag-Bi-Cu-In系无铅钎料合金研究

通过正交试验设计形成Sn-Ag-Bi-Cu-In系无铅钎料合金,并对钎料合金的熔化温度、可焊性、密度及剪切强度等进行研究.研究发现,Sn-Ag-Bi-Cu-In系钎料合金熔化温度接近传统的熔化温度,固-液温度差小;钎料密度约为传统Sn63Pb37的87%;试样铺展面积为72.02mm2,与Sn63Pb37焊锡的铺展面积76.85 mm2非常接近;钎料的剪切强度远大于传统Sn63Pb37钎料的剪切强度,其断裂形貌为沿晶脆断.     

微量元素对Sn-0.7Cu无铅钎料抗氧化性能的影响

以Sn-0.7Cu系无铅钎料合金为基础,添加微量的P、Ge、Ga、RE元素,进行了280℃大气环境下氧化试验,通过对含有不同微量元素的无铅钎料表面氧化状况的对比及分析,研究了不同微量元素对Sn-0.7Cu无铅钎料抗氧化性能的影响。发现当P和Ga同时添加时,得到Sn-0.7Cu-(0.001~0.1)P-(0.0001~0.1)Ga无铅钎料的抗氧化性能高于Sn-0.7Cu-(0.001~0.1)P和Sn-0.7Cu-(0.0001~0.1)Ga的抗氧化性能。     

文献与摘要（48）

新型Al-Si-Cu-Ge系钎料研究该文研究了用于铝合金钎焊的新型Al-Si-Cu-Ge系钎料,通过快冷工艺制备出厚度为90微米到150微米的钎料薄带。对钎料熔化温度区间及金相组织进行了分析和判定,结果表明:与Al-9.6Si-20Cu相比,铅料熔化温度大幅度降低,普通铅料和快冷铅料的固相线相差30度,液相线相差约5度左右,普通铅料的微观组织主要由Al-Si-Cu-Ge、Al-Si-Ge和Al-Cu共晶相、Si-Ge先析出相及θ(Al2Cu)相组成,快冷铅料晶粒尺寸范围约1￣5微米。(张福礼等,电子工艺技术,2005/3,共4页)印制电路板的抗干扰设计以印制电路板的电磁兼容性为核心,分…     

纳米Sn-Ag钎料合金熔化温度及形成焓的研究

考虑表面效应,基于Lindemann熔化准则,利用Miedema模型对Sn-Ag纳米钎料合金的熔化温度及形成焓进行计算.Sn-Ag纳米合金微粒的熔化温度及形成焓均依赖于尺寸和组元成分;对于Sn3.5 Ag纳米钎料合金,当微粒尺寸大小为5nm时,其熔化温度下降约为7％;而合金形成焓随晶粒粒径的减小而增加,合金稳定性降低;对于Sn3.5Ag钎料合金,当粒径尺寸为0.1μm时,合金形成焓完全为正值,对Sn-Ag钎料合金组织形成存在产生很大影响.     

Effects of Rare-Earth Addition on Properties and Microstructure of Lead-Free Solder Balls

In the present work, lead-free solder balls were manufactured by a uniform droplet spray (UDS) method. The solder used to produce solder balls was based on the Sn-3.8Ag-0.7Cu alloy. Different amounts of cerium-based mixed rare-earth (RE) elements were added into the Sn-3.8Ag-0.7Cu solder alloy in order to examine the effects of small amounts of RE additions on the physical properties, microstructure, and surface smoothness of the solder balls. Results show that a small amount of RE addition has no obvious effect on the melting temperature, but it decreases the nucleation undercooling degree. Moreover, a small amount of RE addition (<0.25 wt.%) can improve the surface smoothness of the solder balls. However, when the RE was added up to 0.5 wt.%, the surface smoothness of the solder balls was deteriorated. From observations of the microstructure of the solder balls, it is obvious that the RE addition affects solidification behavior, and as a result, the surface smoothness of the solder balls.     

Properties of lead-free solder SnAgCu containing minute amounts of rare earth

Because of excellent wetting and mechanical properties, SnAgCu solder alloys have been regarded as the most promising Pb-free substitutes for the SnPb solder. The Sn-3.8Ag-0.7Cu solder has garnered attention because of its creep resistance. However, under the drives of increasingly finer pitch design and severe service conditions, novel lead-free solders with higher creep performance may be needed. Adding a surface-active element to an alloy is an effective way to improve the high-temperature performance of the solder. The present work focuses on the effect of rare earth (RE) on the physical properties, spreading property, and mechanical properties of SnAgCu solder. Results show that the creep-rupture life of SnAgCu solder joints at room temperature could be notably increased by adding a minute amount of RE, up to 7 times more than that of SnAgCu solder joints when containing 1.0wt.%RE. The differential scanning calorimetry (DSC) curves indicated that the melting temperature of SnAgCu solder with RE increased a little, and no lower melting-temperature, eutectic endothermal peak appears on the DSC curve. The electrical conductivity of the solder decreased slightly, but it is still superior to the SnPb eutectic solder. Compared to that of SnPb solder, the coefficient of thermal expansion (CTE) of SnAgCu (RE) is closer to copper, which usually serves as the substrate of printed circuit boards (PCBs). It is assumed that this will comparably reduce the thermal stress derived from thermal mismatch between the solder and the PCBs. The RE had no apparent effect on the spreading property, but when RE added up to 1.0 wt.%, the spreading area of the solder on the copper substrate decreased, obviously, because of mass oxide. The RE improved the ultimate tensile strength little, but it increased the elongation up to 30%. However, as the content of the RE increases, the elongation of the solder gradually decreased to the level of SnAgCu when the RE exceeds 0.25 wt.%. Additionally, RE made the elastic modulus of SnAgCu solder increase, so the resistance to elastic deformation of the solder is enhanced. The microstructure of SnAgCuRE led to a refining trend as the RE content increased. The RE compounds appeared in the solder when RE was 0.1 wt.%. This deteriorates the mechanical properties of the solder. The fractography of the tensile specimen containing 0.1 wt.% indicated a superior ductility to Sn-3.8Ag-0.7Cu bulk solder. However, as RE is increased to 1.0 wt.%, the fractography shows less ductile characteristics, which is believed to serve as the reason that the elongation of solder degrades as RE increases. Summarily, the most suitable content of RE is within 0.05–0.5 wt.% and is inadvisable beyond 1.0 wt.%.     

SnAgCuRE系钎料的钎焊接头组织与力学性能

以Sn2.5Ag0.7Cu为基础,添加微量的稀土(RE)r(Ce︰La)为4︰1,研究了钎焊接头的显微组织与力学性能。结果表明:添加微量的RE后,钎料与Cu试样间的界面层厚度明显减小,且界面处的组织更加平滑,相应地其剪切强度随微量RE的添加而增大,并在RE含量(质量分数)为0.1%时达到最大值36MPa。     

Study on the microstructure of a novel lead-free solder alloy SnAgCu-RE and its soldered joints

This paper focused on the microstructure of SnAgCu-rare earth (RE) solder alloy and its small single-lap joints, focusing on phases present and the distribution of RE in the SnAgCu solder. Energy dispersive x-ray (EDX) analysis was used to observed the RE-rich phase. The RE atoms also tended to aggregate at boundaries of primary dendrites in the joints and form as a weblike structure, which surrounded the dendrites and restrained the dendrites from sliding or moving. It is assumed that this would strengthen the boundaries and increase the resistance to creep deformation of the solder matrix. The creep-rupture life of joints can be remarkably increased, at least seven times more than that of SnAgCu at room temperature. The aggregation mechanism of RE at dendrite boundaries in SnAgCu solder joints was presented. The drive for RE atoms to aggregate at the boundary is the difference of the lattice-aberration energy between the interior and the boundaries of the dendrites, which is caused by a solution of RE atoms.     

La对Sn-Ag-Cu无铅钎料组织与性能的影响

研究了微量稀土La对Sn-3.0Ag-0.5Cu无铅钎料显微组织、力学性能、断口形貌、润湿性能和熔点的影响.结果表明:La的质量分数为0.1%可使钎料合金晶粒细化,并显著提高钎料合金力学性能和润湿性能;添加La的质量分数为0.4%将形成粗大LaSn3初生枝晶相,降低力学性能和润湿性能;微量La使钎料合金的熔点轻微增加.     

Creep and Fatigue Behavior of SnAg Solders With Lanthanum Doping

In this paper, extensive testing was conducted to study the effects of Lanthanum (La) doping on the creep and fatigue behavior of SnAg lead free solder alloys. Variables considered in this paper include doping amount, aging temperature, and aging time. The experimental data show that rare earth element (RE) doping increases SnAg solders creep resistance by about 15%. Meanwhile, RE doping does not affect thermal aging behavior of the solder alloy. A microstructure dependent Anand viscoplastic model is proposed to capture the RE doping effect on the creep behavior. Good agreement between the model predictions and experimental data are obtained. In addition, fatigue tests were performed with bulk specimen. It is found that La doping increases the fatigue life by about five times. The optimal doping level for better fatigue performance is around 0.1%.      

<Emphasis Type="Italic">In Situ</Emphasis> Scanning Electron Microscopy Observation of Tensile Deformation in Sn-Ag-Cu Alloys Containing Rare-Earth Elements

The effects of rare-earth (RE) element additions on the tensile deformation mechanism of the Sn-3.8Ag-0.7Cu solder alloy have been investigated. The results show that adding RE elements can remarkably improve the tensile strength and elongation of the Sn-3.8Ag-0.7Cu alloy. The increase in the mechanical properties are attributed to the constraints of microcrack growth and grain boundary sliding in the eutectic phase as well as the relaxation of stress concentration in the β-Sn phase due to the addition of the RE elements. It is considered that the RE elements strengthen the eutectic phase and increase the deformation resistance of this alloy.